diff --git a/collects/plot/common/math.rkt b/collects/plot/common/math.rkt
index edf6584eb5..ec8b57e5c8 100644
--- a/collects/plot/common/math.rkt
+++ b/collects/plot/common/math.rkt
@@ -456,14 +456,13 @@
       [((length vs) . < . 3)  default-normal]
       [else
        (let ([vs  (append vs (take vs 2))])
-         (let/ec break
-           (for ([v1  (in-list vs)]
-                 [v2  (in-list (rest vs))]
-                 [v3  (in-list (rest (rest vs)))])
-             (define norm (vcross (v- v3 v2) (v- v1 v2)))
-             (define m (vmag norm))
-             (when (m . > . 0) (break (v/ norm m))))
-           default-normal))])))
+         (define norm
+           (for/fold ([norm  (vector 0.0 0.0 0.0)]) ([v1  (in-list vs)]
+                                                     [v2  (in-list (rest vs))]
+                                                     [v3  (in-list (rest (rest vs)))])
+             (v+ norm (vcross (v- v3 v2) (v- v1 v2)))))
+         (define m (vmag norm))
+         (if (m . > . 0) (v/ norm m) default-normal))])))
 
 ;; ===================================================================================================
 ;; Intervals
diff --git a/collects/plot/common/non-renderer.rkt b/collects/plot/common/non-renderer.rkt
index 0d4d2e2376..d8768df04c 100644
--- a/collects/plot/common/non-renderer.rkt
+++ b/collects/plot/common/non-renderer.rkt
@@ -35,13 +35,13 @@
 (defproc (z-ticks [ts (listof tick?)] [#:far? far? boolean? #f]) non-renderer?
   (non-renderer #f #f (z-ticks-fun ts far?)))
 
-(defproc (invisible-box [x-min (or/c regular-real? #f)] [x-max (or/c regular-real? #f)]
-                        [y-min (or/c regular-real? #f)] [y-max (or/c regular-real? #f)]
-                        ) non-renderer?
+(defproc (invisible-rect [x-min (or/c regular-real? #f)] [x-max (or/c regular-real? #f)]
+                         [y-min (or/c regular-real? #f)] [y-max (or/c regular-real? #f)]
+                         ) non-renderer?
   (non-renderer (vector (ivl x-min x-max) (ivl y-min y-max)) #f #f))
 
-(defproc (invisible-box3d [x-min (or/c regular-real? #f)] [x-max (or/c regular-real? #f)]
-                          [y-min (or/c regular-real? #f)] [y-max (or/c regular-real? #f)]
-                          [z-min (or/c regular-real? #f)] [z-max (or/c regular-real? #f)]
-                          ) non-renderer?
+(defproc (invisible-rect3d [x-min (or/c regular-real? #f)] [x-max (or/c regular-real? #f)]
+                           [y-min (or/c regular-real? #f)] [y-max (or/c regular-real? #f)]
+                           [z-min (or/c regular-real? #f)] [z-max (or/c regular-real? #f)]
+                           ) non-renderer?
   (non-renderer (vector (ivl x-min x-max) (ivl y-min y-max) (ivl z-min z-max)) #f #f))
diff --git a/collects/plot/common/plot-device.rkt b/collects/plot/common/plot-device.rkt
index 6af331f988..bc1a009217 100644
--- a/collects/plot/common/plot-device.rkt
+++ b/collects/plot/common/plot-device.rkt
@@ -118,10 +118,11 @@
       (send dc set-background old-background)
       (send dc set-alpha old-alpha))
     
-    (define/public (reset-drawing-params)
+    (define/public (reset-drawing-params [clipping-rect? #t])
       (send dc set-smoothing 'smoothed)
       (send dc set-text-mode 'transparent)
-      (send dc set-clipping-rect dc-x-min dc-y-min dc-x-size dc-y-size)
+      (when clipping-rect?
+        (send dc set-clipping-rect dc-x-min dc-y-min dc-x-size dc-y-size))
       (set-font (plot-font-size) (plot-font-family))
       (set-text-foreground (plot-foreground))
       (set-pen (plot-foreground) (plot-line-width) 'solid)
diff --git a/collects/plot/common/sample.rkt b/collects/plot/common/sample.rkt
index 6f9dda8892..d97ea1da93 100644
--- a/collects/plot/common/sample.rkt
+++ b/collects/plot/common/sample.rkt
@@ -154,3 +154,48 @@
                                           (unless (and d-max (d . <= . d-max)) (set! d-max d)))
                                         d)))))
                    (3d-sample xs ys zs dsss d-min d-max))))))
+
+(define-syntax-rule (for-2d-sample (xa xb ya yb z1 z2 z3 z4) sample expr ...)
+  (let ()
+    (match-define (2d-sample xs ys zss fz-min fz-max) sample)
+    (define ya (first ys))
+    (define zs0 (vector-ref zss 0))
+    (for/fold ([ya ya] [zs0 zs0]) ([yb  (in-list (rest ys))]
+                                   [zs1  (in-vector zss 1)])
+      (define xa (first xs))
+      (define z1 (vector-ref zs0 0))
+      (define z4 (vector-ref zs1 0))
+      (for/fold ([xa xa] [z1 z1] [z4 z4]) ([xb  (in-list (rest xs))]
+                                           [z2  (in-vector zs0 1)]
+                                           [z3  (in-vector zs1 1)])
+        expr ...
+        (values xb z2 z3))
+      (values yb zs1))))
+
+(define-syntax-rule (for-3d-sample (xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8) sample expr ...)
+  (let ()
+    (match-define (3d-sample xs ys zs dsss fd-min fd-max) sample)
+    (define za (first zs))
+    (define dss0 (vector-ref dsss 0))
+    (for/fold ([za za] [dss0 dss0]) ([zb  (in-list (rest zs))]
+                                     [dss1  (in-vector dsss 1)])
+      (define ya (first ys))
+      (define ds00 (vector-ref dss0 0))
+      (define ds10 (vector-ref dss1 0))
+      (for/fold ([ya ya] [ds00 ds00] [ds10 ds10]) ([yb  (in-list (rest ys))]
+                                                   [ds01  (in-vector dss0 1)]
+                                                   [ds11  (in-vector dss1 1)])
+        (define xa (first xs))
+        (define d1 (vector-ref ds00 0))
+        (define d4 (vector-ref ds01 0))
+        (define d5 (vector-ref ds10 0))
+        (define d8 (vector-ref ds11 0))
+        (for/fold ([xa xa] [d1 d1] [d4 d4] [d5 d5] [d8 d8]) ([xb  (in-list (rest xs))]
+                                                             [d2  (in-vector ds00 1)]
+                                                             [d3  (in-vector ds01 1)]
+                                                             [d6  (in-vector ds10 1)]
+                                                             [d7  (in-vector ds11 1)])
+          expr ...
+          (values xb d2 d3 d6 d7))
+        (values yb ds01 ds11))
+      (values zb dss1))))
diff --git a/collects/plot/contracted/sample.rkt b/collects/plot/contracted/sample.rkt
index c48b9cd9cb..6a28a7fea4 100644
--- a/collects/plot/contracted/sample.rkt
+++ b/collects/plot/contracted/sample.rkt
@@ -26,4 +26,5 @@
                                 make-3d-function->sampler)
          (contract-out (struct mapped-function ([f (any/c . -> . any/c)]
                                                 [fmap ((listof any/c) . -> . (listof any/c))])))
-         map*)
+         map*
+         for-2d-sample for-3d-sample)
diff --git a/collects/plot/doc.rkt b/collects/plot/doc.rkt
index edf7b7fd92..2deca72659 100644
--- a/collects/plot/doc.rkt
+++ b/collects/plot/doc.rkt
@@ -17,7 +17,8 @@
          "common/draw.rkt"
          "common/date-time.rkt"
          "common/marching-squares.rkt"
-         "common/marching-cubes.rkt")
+         "common/marching-cubes.rkt"
+         "common/legend.rkt")
 
 (provide (only-doc-out
           (combine-out (all-from-out "common/parameters.rkt")
@@ -32,7 +33,8 @@
                        (all-from-out "common/draw.rkt")
                        (all-from-out "common/date-time.rkt")
                        (all-from-out "common/marching-squares.rkt")
-                       (all-from-out "common/marching-cubes.rkt"))))
+                       (all-from-out "common/marching-cubes.rkt")
+                       (all-from-out "common/legend.rkt"))))
 
 ;; ===================================================================================================
 ;; 2D exports
diff --git a/collects/plot/main.rkt b/collects/plot/main.rkt
index 95aa9f559a..92c447de21 100644
--- a/collects/plot/main.rkt
+++ b/collects/plot/main.rkt
@@ -23,7 +23,7 @@
          datetime->real)
 
 (require "common/non-renderer.rkt")
-(provide (activate-contract-out x-ticks y-ticks z-ticks invisible-box invisible-box3d))
+(provide (activate-contract-out x-ticks y-ticks z-ticks invisible-rect invisible-rect3d))
 
 ;; ===================================================================================================
 ;; 2D exports
diff --git a/collects/plot/plot2d/contour.rkt b/collects/plot/plot2d/contour.rkt
index c8ef95d343..9c8a584ce0 100644
--- a/collects/plot/plot2d/contour.rkt
+++ b/collects/plot/plot2d/contour.rkt
@@ -14,25 +14,17 @@
 
 (define ((isoline-render-proc g z samples color width style alpha label) area)
   (match-define (vector (ivl x-min x-max) (ivl y-min y-max)) (send area get-bounds-rect))
-  (match-define (2d-sample xs ys zss z-min z-max)
-    (g x-min x-max samples y-min y-max samples))
+  (define sample (g x-min x-max (animated-samples samples)
+                    y-min y-max (animated-samples samples)))
+  (match-define (2d-sample xs ys zss z-min z-max) sample)
   
   (when (<= z-min z z-max)
     (send area put-alpha alpha)
     (send area put-pen color width style)
-    (for ([ya  (in-list ys)]
-          [yb  (in-list (rest ys))]
-          [zs0  (in-vector zss)]
-          [zs1  (in-vector zss 1)]
-          #:when #t
-          [xa  (in-list xs)]
-          [xb  (in-list (rest xs))]
-          [z1  (in-vector zs0)]
-          [z2  (in-vector zs0 1)]
-          [z3  (in-vector zs1 1)]
-          [z4  (in-vector zs1)])
-      (for/list ([line  (in-list (heights->lines xa xb ya yb z z1 z2 z3 z4))])
-        (send/apply area put-line (map (λ (v) (vector-take v 2)) line)))))
+    (for-2d-sample
+     (xa xb ya yb z1 z2 z3 z4) sample
+     (for/list ([line  (in-list (heights->lines xa xb ya yb z z1 z2 z3 z4))])
+       (send/apply area put-line (map (λ (v) (vector-take v 2)) line)))))
   
   (cond [label  (line-legend-entry label color width style)]
         [else   empty]))
@@ -60,9 +52,9 @@
 (define ((contours-render-proc g levels samples colors widths styles alphas label) area)
   (let/ec return
     (match-define (vector (ivl x-min x-max) (ivl y-min y-max)) (send area get-bounds-rect))
-    (match-define (2d-sample xs ys zss z-min z-max)
-      (g x-min x-max samples y-min y-max samples))
-    
+    (define sample (g x-min x-max (animated-samples samples)
+                      y-min y-max (animated-samples samples)))
+    (match-define (2d-sample xs ys zss z-min z-max) sample)
     (match-define (list (tick zs _ labels) ...) (contour-ticks z-min z-max levels #f))
     
     (let ([colors  (maybe-apply colors zs)]
@@ -76,20 +68,11 @@
             [alpha  (in-cycle alphas)])
         (send area put-alpha alpha)
         (send area put-pen color width style)
-        (for ([ya  (in-list ys)]
-              [yb  (in-list (rest ys))]
-              [zs0  (in-vector zss)]
-              [zs1  (in-vector zss 1)]
-              #:when #t
-              [xa  (in-list xs)]
-              [xb  (in-list (rest xs))]
-              [z1  (in-vector zs0)]
-              [z2  (in-vector zs0 1)]
-              [z3  (in-vector zs1 1)]
-              [z4  (in-vector zs1)])
-          (for/list ([line  (in-list (heights->lines xa xb ya yb z z1 z2 z3 z4))])
-            (match-define (list v1 v2) (map (λ (v) (vector-take v 2)) line))
-            (send area put-line v1 v2))))
+        (for-2d-sample
+         (xa xb ya yb z1 z2 z3 z4) sample
+         (for/list ([line  (in-list (heights->lines xa xb ya yb z z1 z2 z3 z4))])
+           (match-define (list v1 v2) (map (λ (v) (vector-take v 2)) line))
+           (send area put-line v1 v2))))
       
       (cond [label  (line-legend-entries label zs labels colors widths styles)]
             [else   empty]))))
@@ -120,9 +103,9 @@
          area)
   (let/ec return
     (match-define (vector (ivl x-min x-max) (ivl y-min y-max)) (send area get-bounds-rect))
-    (match-define (2d-sample xs ys zss z-min z-max)
-      (g x-min x-max samples y-min y-max samples))
-    
+    (define sample (g x-min x-max (animated-samples samples)
+                      y-min y-max (animated-samples samples)))
+    (match-define (2d-sample xs ys zss z-min z-max) sample)
     (match-define (list (tick zs _ labels) ...) (contour-ticks z-min z-max levels #t))
     
     (define-values (z-ivls ivl-labels)
@@ -132,6 +115,7 @@
                                       [lb  (in-list (rest labels))])
         (values (ivl za zb) (format "[~a,~a]" la lb))))
     
+    (send area put-pen 0 1 'transparent)
     (let ([colors  (map ->brush-color (maybe-apply colors z-ivls))]
           [styles  (map ->brush-style (maybe-apply styles z-ivls))]
           [alphas  (maybe-apply alphas z-ivls)])
@@ -140,27 +124,12 @@
             [color  (in-cycle colors)]
             [style  (in-cycle styles)]
             [alpha  (in-cycle alphas)])
-        (define polys
-          (append*
-           (for/list ([ya  (in-list ys)]
-                      [yb  (in-list (rest ys))]
-                      [zs0  (in-vector zss)]
-                      [zs1  (in-vector zss 1)]
-                      #:when #t
-                      [xa  (in-list xs)]
-                      [xb  (in-list (rest xs))]
-                      [z1  (in-vector zs0)]
-                      [z2  (in-vector zs0 1)]
-                      [z3  (in-vector zs1 1)]
-                      [z4  (in-vector zs1)])
-             (for/list ([poly  (in-list (heights->polys xa xb ya yb za zb z1 z2 z3 z4))])
-               (map (λ (v) (vector-take v 2)) poly)))))
-        
-        (send area put-pen color 1 'transparent)
         (send area put-brush color style)
         (send area put-alpha alpha)
-        (for ([poly  (in-list polys)])
-            (send area put-polygon poly)))
+        (for-2d-sample
+         (xa xb ya yb z1 z2 z3 z4) sample
+         (for/list ([poly  (in-list (heights->polys xa xb ya yb za zb z1 z2 z3 z4))])
+           (send area put-polygon (map (λ (v) (vector-take v 2)) poly)))))
       
       ((contours-render-proc g levels samples contour-colors contour-widths contour-styles alphas #f)
        area)
diff --git a/collects/plot/plot3d/contour.rkt b/collects/plot/plot3d/contour.rkt
index 9e5a7dafb6..3ae3782fcd 100644
--- a/collects/plot/plot3d/contour.rkt
+++ b/collects/plot/plot3d/contour.rkt
@@ -13,28 +13,19 @@
 (define ((isoline3d-render-proc f z samples color width style alpha label) area)
   (match-define (vector (ivl x-min x-max) (ivl y-min y-max) (ivl z-min z-max))
     (send area get-bounds-rect))
-  (match-define (2d-sample xs ys zss fz-min fz-max)
-    (f x-min x-max (animated-samples samples) y-min y-max (animated-samples samples)))
+  (define sample (f x-min x-max (animated-samples samples)
+                    y-min y-max (animated-samples samples)))
   
   (when (<= z-min z z-max)
     (send area put-alpha alpha)
     (send area put-pen color width style)
-    (for ([ya  (in-list ys)]
-          [yb  (in-list (rest ys))]
-          [zs0  (in-vector zss)]
-          [zs1  (in-vector zss 1)]
-          #:when #t
-          [xa  (in-list xs)]
-          [xb  (in-list (rest xs))]
-          [z1  (in-vector zs0)]
-          [z2  (in-vector zs0 1)]
-          [z3  (in-vector zs1 1)]
-          [z4  (in-vector zs1)])
-      (for ([line  (in-list (heights->lines xa xb ya yb z z1 z2 z3 z4))])
-        (match-define (list v1 v2) line)
-        (define center (vector (* 1/2 (+ xa xb)) (* 1/2 (+ ya yb))
-                               (* 1/2 (+ (min z1 z2 z3 z4) (max z1 z2 z3 z4)))))
-        (send area put-line v1 v2 center))))
+    (for-2d-sample
+     (xa xb ya yb z1 z2 z3 z4) sample
+     (for ([line  (in-list (heights->lines xa xb ya yb z z1 z2 z3 z4))])
+       (match-define (list v1 v2) line)
+       (define center (vector (* 1/2 (+ xa xb)) (* 1/2 (+ ya yb))
+                              (* 1/2 (+ (min z1 z2 z3 z4) (max z1 z2 z3 z4)))))
+       (send area put-line v1 v2 center))))
   
   (cond [label  (line-legend-entry label color width style)]
         [else   empty]))
@@ -67,9 +58,8 @@
 (define ((contours3d-render-proc f levels samples colors widths styles alphas label) area)
   (match-define (vector (ivl x-min x-max) (ivl y-min y-max) (ivl z-min z-max))
     (send area get-bounds-rect))
-  (match-define (2d-sample xs ys zss fz-min fz-max)
-    (f x-min x-max (animated-samples samples) y-min y-max (animated-samples samples)))
-  
+  (define sample (f x-min x-max (animated-samples samples)
+                    y-min y-max (animated-samples samples)))
   (match-define (list (tick zs _ labels) ...) (contour-ticks z-min z-max levels #f))
   
   (let ([colors  (maybe-apply colors zs)]
@@ -83,22 +73,13 @@
           [alpha  (in-cycle alphas)])
       (send area put-alpha alpha)
       (send area put-pen color width style)
-      (for ([ya  (in-list ys)]
-            [yb  (in-list (rest ys))]
-            [zs0  (in-vector zss)]
-            [zs1  (in-vector zss 1)]
-            #:when #t
-            [xa  (in-list xs)]
-            [xb  (in-list (rest xs))]
-            [z1  (in-vector zs0)]
-            [z2  (in-vector zs0 1)]
-            [z3  (in-vector zs1 1)]
-            [z4  (in-vector zs1)])
-        (for ([line  (in-list (heights->lines xa xb ya yb z z1 z2 z3 z4))])
-          (match-define (list v1 v2) line)
-          (define center (vector (* 1/2 (+ xa xb)) (* 1/2 (+ ya yb))
-                                 (* 1/2 (+ (min z1 z2 z3 z4) (max z1 z2 z3 z4)))))
-          (send area put-line v1 v2 center))))
+      (for-2d-sample
+       (xa xb ya yb z1 z2 z3 z4) sample
+       (for ([line  (in-list (heights->lines xa xb ya yb z z1 z2 z3 z4))])
+         (match-define (list v1 v2) line)
+         (define center (vector (* 1/2 (+ xa xb)) (* 1/2 (+ ya yb))
+                                (* 1/2 (+ (min z1 z2 z3 z4) (max z1 z2 z3 z4)))))
+         (send area put-line v1 v2 center))))
     
     (cond [label  (line-legend-entries label zs labels colors widths styles)]
           [else   empty])))
@@ -134,8 +115,8 @@
          area)
   (match-define (vector (ivl x-min x-max) (ivl y-min y-max) (ivl z-min z-max))
     (send area get-bounds-rect))
-  (match-define (2d-sample xs ys zss fz-min fz-max)
-    (f x-min x-max (animated-samples samples) y-min y-max (animated-samples samples)))
+  (define sample (f x-min x-max (animated-samples samples) y-min y-max (animated-samples samples)))
+  (match-define (2d-sample xs ys zss fz-min fz-max) sample)
   
   (match-define (list (tick zs _ labels) ...) (contour-ticks z-min z-max levels #t))
   
@@ -163,22 +144,13 @@
       (send area put-alpha alpha)
       (send area put-pen line-color line-width line-style)
       (send area put-brush color style)
-      (for ([ya  (in-list ys)]
-            [yb  (in-list (rest ys))]
-            [zs0  (in-vector zss)]
-            [zs1  (in-vector zss 1)]
-            #:when #t
-            [xa  (in-list xs)]
-            [xb  (in-list (rest xs))]
-            [z1  (in-vector zs0)]
-            [z2  (in-vector zs0 1)]
-            [z3  (in-vector zs1 1)]
-            [z4  (in-vector zs1)])
-        (for ([poly  (in-list (heights->polys xa xb ya yb za zb z1 z2 z3 z4))])
-          (define center (vector (* 1/2 (+ xa xb))
-                                 (* 1/2 (+ ya yb))
-                                 (* 1/2 (+ (min z1 z2 z3 z4) (max z1 z2 z3 z4)))))
-          (send area put-polygon poly center))))
+      (for-2d-sample
+       (xa xb ya yb z1 z2 z3 z4) sample
+       (for ([poly  (in-list (heights->polys xa xb ya yb za zb z1 z2 z3 z4))])
+         (define center (vector (* 1/2 (+ xa xb))
+                                (* 1/2 (+ ya yb))
+                                (* 1/2 (+ (min z1 z2 z3 z4) (max z1 z2 z3 z4)))))
+         (send area put-polygon poly center))))
     
     ((contours3d-render-proc f levels samples contour-colors contour-widths contour-styles alphas #f)
      area)
diff --git a/collects/plot/plot3d/isosurface.rkt b/collects/plot/plot3d/isosurface.rkt
index 4a4ec70588..3cca673655 100644
--- a/collects/plot/plot3d/isosurface.rkt
+++ b/collects/plot/plot3d/isosurface.rkt
@@ -14,41 +14,20 @@
          area)
   (match-define (vector (ivl x-min x-max) (ivl y-min y-max) (ivl z-min z-max))
     (send area get-bounds-rect))
-  (match-define (3d-sample xs ys zs dsss d-min d-max)
-    (f x-min x-max (animated-samples samples)
-       y-min y-max (animated-samples samples)
-       z-min z-max (animated-samples samples)))
+  (define sample (f x-min x-max (animated-samples samples)
+                    y-min y-max (animated-samples samples)
+                    z-min z-max (animated-samples samples)))
+  (match-define (3d-sample xs ys zs dsss d-min d-max) sample)
   
   (send area put-alpha alpha)
   (send area put-brush color style)
   (send area put-pen line-color line-width line-style)
-  (for ([za  (in-list zs)]
-        [zb  (in-list (rest zs))]
-        [dss0  (in-vector dsss)]
-        [dss1  (in-vector dsss 1)]
-        #:when #t
-        [ya  (in-list ys)]
-        [yb  (in-list (rest ys))]
-        [ds00  (in-vector dss0)]
-        [ds01  (in-vector dss0 1)]
-        [ds10  (in-vector dss1)]
-        [ds11  (in-vector dss1 1)]
-        #:when #t
-        [xa  (in-list xs)]
-        [xb  (in-list (rest xs))]
-        [d1  (in-vector ds00)]
-        [d2  (in-vector ds00 1)]
-        [d3  (in-vector ds01 1)]
-        [d4  (in-vector ds01)]
-        [d5  (in-vector ds10)]
-        [d6  (in-vector ds10 1)]
-        [d7  (in-vector ds11 1)]
-        [d8  (in-vector ds11)])
-    (define polys (heights->cube-polys xa xb ya yb za zb d d1 d2 d3 d4 d5 d6 d7 d8))
-    
-    (when (not (empty? polys))
-      (send area put-polygons polys
-            (vector (* 1/2 (+ xa xb)) (* 1/2 (+ ya yb)) (* 1/2 (+ za zb))))))
+  (for-3d-sample
+   (xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8) sample
+   (define polys (heights->cube-polys xa xb ya yb za zb d d1 d2 d3 d4 d5 d6 d7 d8))
+   (when (not (empty? polys))
+     (send area put-polygons polys
+           (vector (* 1/2 (+ xa xb)) (* 1/2 (+ ya yb)) (* 1/2 (+ za zb))))))
   
   (cond [label  (rectangle-legend-entry
                  label color style line-color line-width line-style)]
@@ -83,10 +62,10 @@
          area)
   (match-define (vector (ivl x-min x-max) (ivl y-min y-max) (ivl z-min z-max))
     (send area get-bounds-rect))
-  (match-define (3d-sample xs ys zs dsss fd-min fd-max)
-    (f x-min x-max (animated-samples samples)
-       y-min y-max (animated-samples samples)
-       z-min z-max (animated-samples samples)))
+  (define sample (f x-min x-max (animated-samples samples)
+                    y-min y-max (animated-samples samples)
+                    z-min z-max (animated-samples samples)))
+  (match-define (3d-sample xs ys zs dsss fd-min fd-max) sample)
   
   (define d-min (if rd-min rd-min fd-min))
   (define d-max (if rd-max rd-max fd-max))
@@ -113,32 +92,12 @@
          (send area put-alpha alpha)
          (send area put-brush color style)
          (send area put-pen line-color line-width line-style)
-         (for ([za  (in-list zs)]
-               [zb  (in-list (rest zs))]
-               [dss0  (in-vector dsss)]
-               [dss1  (in-vector dsss 1)]
-               #:when #t
-               [ya  (in-list ys)]
-               [yb  (in-list (rest ys))]
-               [ds00  (in-vector dss0)]
-               [ds01  (in-vector dss0 1)]
-               [ds10  (in-vector dss1)]
-               [ds11  (in-vector dss1 1)]
-               #:when #t
-               [xa  (in-list xs)]
-               [xb  (in-list (rest xs))]
-               [d1  (in-vector ds00)]
-               [d2  (in-vector ds00 1)]
-               [d3  (in-vector ds01 1)]
-               [d4  (in-vector ds01)]
-               [d5  (in-vector ds10)]
-               [d6  (in-vector ds10 1)]
-               [d7  (in-vector ds11 1)]
-               [d8  (in-vector ds11)])
-           (define polys (heights->cube-polys xa xb ya yb za zb d d1 d2 d3 d4 d5 d6 d7 d8))
-           (when (not (empty? polys))
-             (send area put-polygons polys
-                   (vector (* 1/2 (+ xa xb)) (* 1/2 (+ ya yb)) (* 1/2 (+ za zb)))))))
+         (for-3d-sample
+          (xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8) sample
+          (define polys (heights->cube-polys xa xb ya yb za zb d d1 d2 d3 d4 d5 d6 d7 d8))
+          (when (not (empty? polys))
+            (send area put-polygons polys
+                  (vector (* 1/2 (+ xa xb)) (* 1/2 (+ ya yb)) (* 1/2 (+ za zb)))))))
        
        (cond
          [label  (rectangle-legend-entries
@@ -173,56 +132,37 @@
          area)
   (match-define (vector (ivl x-min x-max) (ivl y-min y-max) (ivl z-min z-max))
     (send area get-bounds-rect))
-  (match-define (3d-sample xs ys zs dsss d-min d-max)
-    (g x-min x-max (animated-samples samples)
-       y-min y-max (animated-samples samples)
-       z-min z-max (animated-samples samples)))
+  (define sample (g x-min x-max (animated-samples samples)
+                    y-min y-max (animated-samples samples)
+                    z-min z-max (animated-samples samples)))
+  (match-define (3d-sample xs ys zs dsss d-min d-max) sample)
+  
+  (define (draw-cube xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8)
+    (define polys (heights->cube-polys xa xb ya yb za zb 0.0 d1 d2 d3 d4 d5 d6 d7 d8))
+    (when (not (empty? polys))
+      (send area put-polygons polys
+            (vector (* 1/2 (+ xa xb)) (* 1/2 (+ ya yb)) (* 1/2 (+ za zb))))))
   
   (send area put-alpha alpha)
   (send area put-brush color style)
   (send area put-pen line-color line-width line-style)
-  (for ([za  (in-list zs)]
-        [zb  (in-list (rest zs))]
-        [dss0  (in-vector dsss)]
-        [dss1  (in-vector dsss 1)]
-        #:when #t
-        [ya  (in-list ys)]
-        [yb  (in-list (rest ys))]
-        [ds00  (in-vector dss0)]
-        [ds01  (in-vector dss0 1)]
-        [ds10  (in-vector dss1)]
-        [ds11  (in-vector dss1 1)]
-        #:when #t
-        [xa  (in-list xs)]
-        [xb  (in-list (rest xs))]
-        [d1  (in-vector ds00)]
-        [d2  (in-vector ds00 1)]
-        [d3  (in-vector ds01 1)]
-        [d4  (in-vector ds01)]
-        [d5  (in-vector ds10)]
-        [d6  (in-vector ds10 1)]
-        [d7  (in-vector ds11 1)]
-        [d8  (in-vector ds11)])
-    (define (draw-cube xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8)
-      (define polys (heights->cube-polys xa xb ya yb za zb 0.0 d1 d2 d3 d4 d5 d6 d7 d8))
-      (when (not (empty? polys))
-        (send area put-polygons polys
-              (vector (* 1/2 (+ xa xb)) (* 1/2 (+ ya yb)) (* 1/2 (+ za zb))))))
-    (cond [(and (xb . > . 0) (ya . < . 0) (yb . > . 0))
-           (let* ([yb  -0.00001]
-                  [d3  (f xb yb za)]
-                  [d4  (f xa yb za)]
-                  [d7  (f xb yb zb)]
-                  [d8  (f xa yb zb)])
-             (draw-cube xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8))
-           (let* ([ya  0.00001]
-                  [d1  (f xa ya za)]
-                  [d2  (f xb ya za)]
-                  [d5  (f xa ya zb)]
-                  [d6  (f xb ya zb)])
-             (draw-cube xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8))]
-          [else
-           (draw-cube xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8)]))
+  (for-3d-sample
+   (xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8) sample
+   (cond [(and (xb . > . 0) (ya . < . 0) (yb . > . 0))
+          (let* ([yb  -0.00001]
+                 [d3  (f xb yb za)]
+                 [d4  (f xa yb za)]
+                 [d7  (f xb yb zb)]
+                 [d8  (f xa yb zb)])
+            (draw-cube xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8))
+          (let* ([ya  0.00001]
+                 [d1  (f xa ya za)]
+                 [d2  (f xb ya za)]
+                 [d5  (f xa ya zb)]
+                 [d6  (f xb ya zb)])
+            (draw-cube xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8))]
+         [else
+          (draw-cube xa xb ya yb za zb d1 d2 d3 d4 d5 d6 d7 d8)]))
   
   (cond [label  (rectangle-legend-entry
                  label color style line-color line-width line-style)]
diff --git a/collects/plot/plot3d/matrix.rkt b/collects/plot/plot3d/matrix.rkt
index 5971f7a2df..5b28403880 100644
--- a/collects/plot/plot3d/matrix.rkt
+++ b/collects/plot/plot3d/matrix.rkt
@@ -2,7 +2,7 @@
 
 ;; A small rotation matrix library, used to transform plot coordinates into view coordinates.
 
-(require racket/match
+(require racket/match racket/flonum
          "../common/math.rkt")
 
 (provide m3-apply m3-transpose m3* m3-rotate-z m3-rotate-x m3-scale)
diff --git a/collects/plot/plot3d/plot-area.rkt b/collects/plot/plot3d/plot-area.rkt
index 62732ad0bc..f0fc8b90a2 100644
--- a/collects/plot/plot3d/plot-area.rkt
+++ b/collects/plot/plot3d/plot-area.rkt
@@ -129,7 +129,9 @@
     ;; coordinates.
     
     (define scale-matrix (m3-scale (/ x-size) (/ y-size) (/ z-size)))
-    (define rotation-matrix (m3* (m3-rotate-x rho) (m3-rotate-z theta)))
+    (define rotate-theta-matrix (m3-rotate-z theta))
+    (define rotate-rho-matrix (m3-rotate-x rho))
+    (define rotation-matrix (m3* rotate-rho-matrix rotate-theta-matrix))
     (define transform-matrix (m3* rotation-matrix scale-matrix))
     
     (define (plot->norm v) (m3-apply scale-matrix (center (axis-transform v))))
@@ -138,11 +140,11 @@
     
     (define transform-matrix/no-rho (m3* (m3-rotate-z theta) scale-matrix))
     (define (plot->view/no-rho v) (m3-apply transform-matrix/no-rho (center (axis-transform v))))
+    (define (rotate/rho v) (m3-apply rotate-rho-matrix v))
     
     (define view->dc #f)
     (define (plot->dc/no-axis-trans v) (view->dc (m3-apply transform-matrix (center v))))
-    (define (plot->dc* v) (view->dc (plot->view v)))
-    (define (plot->dc v) (plot->dc* v))
+    (define (plot->dc v) (view->dc (plot->view v)))
     
     (define-values (view-x-size view-y-size view-z-size)
       (match-let ([(vector view-x-ivl view-y-ivl view-z-ivl)
@@ -208,7 +210,7 @@
     
     (define near-dist^2 (sqr (* 3 (plot-line-width))))
     (define (vnear? v1 v2)
-      ((vmag^2 (v- (plot->dc* v1) (plot->dc* v2))) . <= . near-dist^2))
+      ((vmag^2 (v- (plot->dc v1) (plot->dc v2))) . <= . near-dist^2))
     
     (define ((x-ticks-near? y) t1 t2)
       (vnear? (vector (pre-tick-value t1) y z-min)
@@ -257,13 +259,13 @@
     (define (y-tick-value->view y) (plot->view (vector y-axis-x y z-min)))
     (define (x-tick-value->dc x) (view->dc (x-tick-value->view x)))
     (define (y-tick-value->dc y) (view->dc (y-tick-value->view y)))
-    (define (z-tick-value->dc z) (plot->dc* (vector z-axis-x z-axis-y z)))
+    (define (z-tick-value->dc z) (plot->dc (vector z-axis-x z-axis-y z)))
     
     (define (x-far-tick-value->view x) (plot->view (vector x x-far-axis-y z-min)))
     (define (y-far-tick-value->view y) (plot->view (vector y-far-axis-x y z-min)))
     (define (x-far-tick-value->dc x) (view->dc (x-far-tick-value->view x)))
     (define (y-far-tick-value->dc y) (view->dc (y-far-tick-value->view y)))
-    (define (z-far-tick-value->dc z) (plot->dc* (vector z-far-axis-x z-far-axis-y z)))
+    (define (z-far-tick-value->dc z) (plot->dc (vector z-far-axis-x z-far-axis-y z)))
     
     (define (get-tick-params ticks tick-value->dc angle)
       (for/list ([t  (in-list ticks)])
@@ -442,7 +444,7 @@
             'top (- (if y-axis-x-min? pi 0) (y-axis-angle))))
     
     (define (get-z-label-params)
-      (list (plot-z-label) (v+ (plot->dc* (vector z-axis-x z-axis-y z-max))
+      (list (plot-z-label) (v+ (plot->dc (vector z-axis-x z-axis-y z-max))
                                (vector 0 (- half-char-height)))
             'bottom-left 0))
     
@@ -459,7 +461,7 @@
             'bottom (- (if y-axis-x-min? pi 0) (y-axis-angle))))
     
     (define (get-z-far-label-params)
-      (list (plot-z-far-label) (v+ (plot->dc* (vector z-far-axis-x z-far-axis-y z-max))
+      (list (plot-z-far-label) (v+ (plot->dc (vector z-far-axis-x z-far-axis-y z-max))
                                    (vector 0 (- half-char-height)))
             'bottom-right 0))
     
@@ -587,53 +589,55 @@
     (define (add-shape! shape) (set! render-list (cons shape render-list)))
     (define (add-shapes! shapes) (set! render-list (append shapes render-list)))
     
-    (define (draw-shapes lst)
-      (for ([s  (in-list (depth-sort (reverse lst) plot->view/no-rho))])
-        (draw-shape s)))
+    (define (draw-shapes ss)
+      (define s+cs (map (λ (s) (cons s (plot->view/no-rho (shape-center s)))) ss))
+      (for ([s+c  (in-list (depth-sort (reverse s+cs)))])
+        (match-define (cons s c) s+c)
+        (draw-shape s (rotate/rho c))))
     
     (define (draw-polygon alpha center vs norm pen-color pen-width pen-style brush-color brush-style)
-      (define-values (diff spec) (get-light-values (plot->view center) (norm->view norm)))
+      (define-values (diff spec) (get-light-values center (norm->view norm)))
       (let ([pen-color  (map (λ (v) (+ (* v diff) spec)) pen-color)]
             [brush-color  (map (λ (v) (+ (* v diff) spec)) brush-color)])
         (send pd set-pen pen-color pen-width pen-style)
         (send pd set-brush brush-color brush-style)
         (send pd draw-polygon (map (λ (v) (plot->dc v)) vs))))
     
-    (define (draw-shape s)
+    (define (draw-shape s center)
       (send pd set-alpha (shape-alpha s))
       (match s
         ;; shapes
-        [(shapes alpha center ss)  (draw-shapes ss)]
+        [(shapes alpha _ ss)  (draw-shapes ss)]
         ;; polygon
-        [(polygon alpha center vs norm pen-color pen-width pen-style brush-color brush-style)
+        [(polygon alpha _ vs norm pen-color pen-width pen-style brush-color brush-style)
          (draw-polygon alpha center vs norm pen-color pen-width pen-style brush-color brush-style)]
         ;; rectangle
-        [(rectangle alpha center r pen-color pen-width pen-style brush-color brush-style)
+        [(rectangle alpha _ r pen-color pen-width pen-style brush-color brush-style)
          (for ([face  (in-list (rect-visible-faces r theta))])
            (match face
              [(list norm vs ...)  (draw-polygon alpha center vs norm pen-color pen-width pen-style
                                                 brush-color brush-style)]
              [_  (void)]))]
         ;; line
-        [(line alpha center v1 v2 pen-color pen-width pen-style)
+        [(line alpha _ v1 v2 pen-color pen-width pen-style)
          (send pd set-pen pen-color pen-width pen-style)
          (send pd draw-line (plot->dc v1) (plot->dc v2))]
         ;; text
-        [(text alpha center anchor angle str font-size font-family color)
+        [(text alpha _ anchor angle str font-size font-family color)
          (send pd set-font font-size font-family)
          (send pd set-text-foreground color)
-         (send pd draw-text str (plot->dc center) anchor angle)]
+         (send pd draw-text str (view->dc center) anchor angle)]
         ;; glyph
-        [(glyph alpha center symbol size pen-color pen-width pen-style brush-color brush-style)
+        [(glyph alpha _ symbol size pen-color pen-width pen-style brush-color brush-style)
          (send pd set-pen pen-color pen-width pen-style)
          (send pd set-brush brush-color brush-style)
-         (send pd draw-glyphs (list (plot->dc center)) symbol size)]
+         (send pd draw-glyphs (list (view->dc center)) symbol size)]
         ;; tick glyph
-        [(tick-glyph alpha center radius angle pen-color pen-width pen-style)
+        [(tick-glyph alpha _ radius angle pen-color pen-width pen-style)
          (send pd set-pen pen-color pen-width pen-style)
-         (send pd draw-tick (plot->dc center) radius angle)]
+         (send pd draw-tick (view->dc center) radius angle)]
         ;; arrow glyph
-        [(arrow-glyph alpha center v1 v2 pen-color pen-width pen-style)
+        [(arrow-glyph alpha _ v1 v2 pen-color pen-width pen-style)
          (send pd set-pen pen-color pen-width pen-style)
          (send pd draw-arrow (plot->dc v1) (plot->dc v2))]
         [_  (error 'draw-shapes "shape not implemented: ~e" s)]))
@@ -702,34 +706,6 @@
       (draw-ticks (get-front-tick-params))
       (draw-labels (get-front-label-params)))
     
-    (define (draw-angles*)
-      (define angle-str (format " angle = ~a " (number->string (round angle))))
-      (define alt-str (format " altitude = ~a " (number->string (round altitude))))
-      (define-values (angle-width angle-height baseline _angle2) (send pd get-text-extent angle-str))
-      (define-values (alt-width alt-height _alt1 _alt2) (send pd get-text-extent alt-str))
-      
-      (define box-x-size (max angle-width alt-width))
-      (define box-y-size (+ angle-height alt-height (* 3 baseline)))
-      (define box-x-min (+ dc-x-min (* 1/2 (- dc-x-size box-x-size))))
-      (define box-y-min (+ dc-y-min (* 1/2 (- dc-y-size box-y-size))))
-      (define box-x-max (+ box-x-min box-x-size))
-      (define box-y-max (+ box-y-min box-y-size))
-      
-      (send pd set-alpha 1/2)
-      (send pd set-minor-pen)
-      (send pd set-brush (plot-background) 'solid)
-      (send pd draw-rect (vector (ivl box-x-min box-x-max) (ivl box-y-min box-y-max)))
-      
-      (send pd set-alpha 1)
-      (send pd draw-text
-            angle-str (vector box-x-min (+ box-y-min baseline))
-            'top-left #:outline? #t)
-      (send pd draw-text
-            alt-str (vector box-x-min (+ box-y-min baseline char-height))
-            'top-left #:outline? #t))
-    
-    (define/public (draw-angles) (draw-angles*))
-    
     (define (draw-legend* legend-entries)
       (define gap-size (+ (pen-gap) tick-radius))
       (send pd draw-legend legend-entries
@@ -820,7 +796,7 @@
                  (add-shape! (line alpha c v1 v2
                                    pen-color pen-width pen-style))]
                 [else
-                 (define vs (subdivide-line plot->dc* v1 v2))
+                 (define vs (subdivide-line plot->dc v1 v2))
                  (for ([v1  (in-list vs)] [v2  (in-list (rest vs))])
                    (add-shape! (line alpha c v1 v2 pen-color pen-width pen-style)))]))))
     
@@ -841,7 +817,7 @@
                                       clip-y-min clip-y-max
                                       clip-z-min clip-z-max)
                         vs)]
-               [vs  (if identity-transforms? vs (subdivide-polygon plot->dc* vs))])
+               [vs  (if identity-transforms? vs (subdivide-polygon plot->dc vs))])
           (when (empty? vs) (return lst))
           (cons (polygon alpha c vs norm pen-color pen-width pen-style brush-color brush-style)
                 lst))))
diff --git a/collects/plot/plot3d/plot.rkt b/collects/plot/plot3d/plot.rkt
index 5a36698dd3..5617724200 100644
--- a/collects/plot/plot3d/plot.rkt
+++ b/collects/plot/plot3d/plot.rkt
@@ -41,7 +41,7 @@
             (rect-zero-area? plot-bounds-rect))
     (match-define (vector (ivl x-min x-max) (ivl y-min y-max) (ivl z-min z-max)) plot-bounds-rect)
     (error 'plot "could not determine sensible plot bounds; got x ∈ [~a,~a], y ∈ [~a,~a], z ∈ [~a,~a]"
-            x-min x-max y-min y-max z-min z-max))
+           x-min x-max y-min y-max z-min z-max))
   
   (rect-inexact->exact plot-bounds-rect))
 
@@ -80,15 +80,11 @@
   
   (send area end-renderers)
   
-  (when (and (not (empty? legend-entries))
-             (or (not (plot-animating?))
-                 (not (equal? (plot-legend-anchor) 'center))))
+  (when (not (empty? legend-entries))
     (send area draw-legend legend-entries))
   
-  (when (plot-animating?) (send area draw-angles))
-  
   (send area end-plot))
-  
+
 
 (defproc (plot3d/dc [renderer-tree  (treeof (or/c renderer3d? non-renderer?))]
                     [dc  (is-a?/c dc<%>)]
@@ -167,9 +163,9 @@
                       [#:z-label z-label (or/c string? #f) (plot-z-label)]
                       [#:legend-anchor legend-anchor anchor/c (plot-legend-anchor)]
                       ) pict?
-  (define saved-values (plot-parameters))
+  (define saved-plot-parameters (plot-parameters))
   (dc (λ (dc x y)
-        (parameterize/group ([plot-parameters  saved-values])
+        (parameterize/group ([plot-parameters  saved-plot-parameters])
           (plot3d/dc renderer-tree dc x y width height
                      #:x-min x-min #:x-max x-max #:y-min y-min #:y-max y-max #:z-min z-min
                      #:z-max z-max #:angle angle #:altitude altitude #:title title #:x-label x-label
@@ -194,57 +190,54 @@
                       [#:z-label z-label (or/c string? #f) (plot-z-label)]
                       [#:legend-anchor legend-anchor anchor/c (plot-legend-anchor)]
                       ) (is-a?/c image-snip%)
-  (define renderer-list (get-renderer-list renderer-tree))
-  (define bounds-rect (get-bounds-rect renderer-list x-min x-max y-min y-max z-min z-max))
-  (define-values (x-ticks x-far-ticks y-ticks y-far-ticks z-ticks z-far-ticks)
-    (get-ticks renderer-list bounds-rect))
-  
-  (define render-list-hash (make-hash))
-  (define legend-entries-hash (make-hash))
-  
-  (make-3d-plot-snip
-   (λ (anim? angle altitude)
-     (parameterize ([plot-animating?     (if anim? #t (plot-animating?))]
-                    [plot3d-angle        angle]
-                    [plot3d-altitude     altitude]
-                    [plot-title          title]
-                    [plot-x-label        x-label]
-                    [plot-y-label        y-label]
-                    [plot-z-label        z-label]
-                    [plot-legend-anchor  legend-anchor])
-       ((if (plot-animating?) draw-bitmap draw-bitmap/supersampling)
-        (λ (dc)
-          (define area (make-object 3d-plot-area%
-                         bounds-rect x-ticks x-far-ticks y-ticks y-far-ticks z-ticks z-far-ticks
-                         dc 0 0 width height))
-          (send area start-plot)
-          
-          (cond [(not (hash-ref render-list-hash (plot-animating?) #f))
-                 (hash-set!
-                  legend-entries-hash (plot-animating?)
-                  (flatten (for/list ([rend  (in-list renderer-list)])
-                             (match-define (renderer3d rend-bounds-rect _bf _tf render-proc) rend)
-                             (send area start-renderer (cond [rend-bounds-rect  rend-bounds-rect]
-                                                             [else  (empty-rect 3)]))
-                             (if render-proc (render-proc area) empty))))
-                 
-                 (hash-set! render-list-hash (plot-animating?) (send area get-render-list))]
-                [else
-                 (send area put-render-list (hash-ref render-list-hash (plot-animating?)))])
-          
-          (send area end-renderers)
-          
-          (define legend-entries (hash-ref legend-entries-hash (plot-animating?) #f))
-          (when (and (not (empty? legend-entries))
-                     (or (not (plot-animating?))
-                         (not (equal? (plot-legend-anchor) 'center))))
-            (send area draw-legend legend-entries))
-          
-          (when (plot-animating?) (send area draw-angles))
-          
-          (send area end-plot))
-        width height)))
-   angle altitude))
+  (parameterize ([plot-title          title]
+                 [plot-x-label        x-label]
+                 [plot-y-label        y-label]
+                 [plot-z-label        z-label]
+                 [plot-legend-anchor  legend-anchor])
+    (define saved-plot-parameters (plot-parameters))
+    (define renderer-list (get-renderer-list renderer-tree))
+    (define bounds-rect (get-bounds-rect renderer-list x-min x-max y-min y-max z-min z-max))
+    (define-values (x-ticks x-far-ticks y-ticks y-far-ticks z-ticks z-far-ticks)
+      (get-ticks renderer-list bounds-rect))
+    
+    (define render-list-hash (make-hash))
+    (define legend-entries-hash (make-hash))
+    
+    (make-3d-plot-snip
+     (λ (anim? angle altitude)
+       (parameterize ([plot-animating?     (if anim? #t (plot-animating?))]
+                      [plot3d-angle        angle]
+                      [plot3d-altitude     altitude])
+         ((if (plot-animating?) draw-bitmap draw-bitmap/supersampling)
+          (λ (dc)
+            (define area (make-object 3d-plot-area%
+                           bounds-rect x-ticks x-far-ticks y-ticks y-far-ticks z-ticks z-far-ticks
+                           dc 0 0 width height))
+            (send area start-plot)
+            
+            (cond [(not (hash-ref render-list-hash (plot-animating?) #f))
+                   (hash-set!
+                    legend-entries-hash (plot-animating?)
+                    (flatten (for/list ([rend  (in-list renderer-list)])
+                               (match-define (renderer3d rend-bounds-rect _bf _tf render-proc) rend)
+                               (send area start-renderer (cond [rend-bounds-rect  rend-bounds-rect]
+                                                               [else  (empty-rect 3)]))
+                               (if render-proc (render-proc area) empty))))
+                   
+                   (hash-set! render-list-hash (plot-animating?) (send area get-render-list))]
+                  [else
+                   (send area put-render-list (hash-ref render-list-hash (plot-animating?)))])
+            
+            (send area end-renderers)
+            
+            (define legend-entries (hash-ref legend-entries-hash (plot-animating?) #f))
+            (when (not (empty? legend-entries))
+              (send area draw-legend legend-entries))
+            
+            (send area end-plot))
+          width height)))
+     angle altitude saved-plot-parameters)))
 
 ;; Plot to a frame
 (defproc (plot3d-frame [renderer-tree (treeof (or/c renderer3d? non-renderer?))]
diff --git a/collects/plot/plot3d/shape.rkt b/collects/plot/plot3d/shape.rkt
index ab94081a72..cff5307d88 100644
--- a/collects/plot/plot3d/shape.rkt
+++ b/collects/plot/plot3d/shape.rkt
@@ -17,14 +17,13 @@
 (struct shapes shape (list) #:transparent)
 
 (define (draw-before? cs1 cs2)
-  (match-define (cons (vector x1 y1 z1) s1) cs1)
-  (match-define (cons (vector x2 y2 z2) s2) cs2)
+  (match-define (cons s1 (vector x1 y1 z1)) cs1)
+  (match-define (cons s2 (vector x2 y2 z2)) cs2)
   (or (y1 . > . y2)
       (and (y1 . = . y2)
            (if (z1 . = . z2)
                (and (polygon? s1) (not (polygon? s2)))
                (z1 . < . z2)))))
 
-(define (depth-sort shapes f)
-  (map cdr (sort (map (λ (s) (cons (f (shape-center s)) s)) shapes)
-                 draw-before?)))
+(define (depth-sort s+cs)
+  (sort s+cs draw-before?))
diff --git a/collects/plot/plot3d/snip.rkt b/collects/plot/plot3d/snip.rkt
index 3c01cad3d5..ce62e4068b 100644
--- a/collects/plot/plot3d/snip.rkt
+++ b/collects/plot/plot3d/snip.rkt
@@ -1,35 +1,40 @@
 #lang racket/base
 
-(require racket/gui/base racket/class racket/match racket/list
+(require racket/gui/base racket/class racket/match racket/list unstable/parameter-group
          "../common/gui.rkt"
          "../common/math.rkt"
          "../common/worker-thread.rkt"
+         "../common/plot-device.rkt"
+         "../common/parameters.rkt"
          "plot-area.rkt")
 
 (provide 3d-plot-snip% make-3d-plot-snip)
 
-(define update-delay 33)  ; about 30 fps (just over)
+(define update-delay 16)  ; about 60 fps (just over)
+(define message-timeout 2000)
 
 (struct draw-command (animating? angle altitude) #:transparent)
-(struct copy-command () #:transparent)
 
-(define (make-render-thread make-bm)
+(define (make-render-thread make-bm saved-plot-parameters)
   (make-worker-thread
    (match-lambda
-     [(draw-command animating? angle altitude)  (make-bm animating? angle altitude)]
-     [(copy-command)  (make-render-thread make-bm)])))
+     [(draw-command animating? angle altitude)
+      (parameterize/group ([plot-parameters  saved-plot-parameters])
+        (make-bm animating? angle altitude))])))
 
 (define (clamp x mn mx) (min* (max* x mn) mx))
 
 (define 3d-plot-snip%
   (class image-snip%
-    (init-field make-bm angle altitude
-                [bm (make-bm #f angle altitude)]
-                [rth (make-render-thread make-bm)])
+    (init-field make-bm angle altitude saved-plot-parameters
+                [bm (make-bm #f angle altitude)])
     (inherit set-bitmap)
     
     (super-make-object bm)
     
+    (define/override (copy)
+      (make-object this% make-bm angle altitude saved-plot-parameters bm))
+    
     (define width (send bm get-width))
     (define height (send bm get-height))
     
@@ -41,73 +46,161 @@
     (define (new-angle) (real-modulo (+ angle (* (- left-drag-x left-click-x) (/ 180 width))) 360))
     (define (new-altitude) (clamp (+ altitude (* (- left-drag-y left-click-y) (/ 180 height))) 0 90))
     
-    (define draw? #t)
-    (define timer #f)
+    (define (refresh)
+      ;(printf "refreshing ~a~n" (current-milliseconds))
+      (send this set-bitmap bm))
     
-    (define ((update animating?))
+    (define draw? #t)
+    (define update-timer #f)
+    (define rth (make-render-thread make-bm saved-plot-parameters))
+    
+    (define (stop-update-timer)
+      (when update-timer
+        (send update-timer stop)
+        (set! update-timer #f)))
+    
+    (define (start-update-timer)
+      (stop-update-timer)
+      (set! update-timer (make-object timer% update update-delay)))
+    
+    (define (update)
+      ;(printf "update ~a~n" (current-milliseconds))
       (define can-draw?
         (cond [(worker-thread-working? rth)
                (define new-bm (worker-thread-try-get rth))
                (cond [(is-a? new-bm bitmap%)  (set! bm new-bm)
+                                              (set-angles-message (new-angle) (new-altitude))
                                               (set-bitmap bm)
                                               #t]
                      [else  #f])]
               [else  #t]))
       (when (and draw? can-draw?)
         (set! draw? #f)
-        (worker-thread-put rth (draw-command animating? (new-angle) (new-altitude)))))
+        (worker-thread-put rth (draw-command #t (new-angle) (new-altitude))))
+      (refresh-message-timer))
     
-    (define (stop-timer)
-      (when timer
-        (send timer stop)
-        (set! timer #f)))
+    (define message #f)
+    (define message-timer #f)
     
-    (define (start-timer)
-      (stop-timer)
-      (set! timer (make-object timer% (update #t) update-delay)))
+    (define (stop-message)
+      ;(printf "stop-message ~a~n" (current-milliseconds))
+      (when message-timer
+        (send message-timer stop)
+        (set! message-timer #f)
+        (set! message #f)
+        (refresh)))
+    
+    (define (refresh-message-timer)
+      (when message-timer
+        (send message-timer stop))
+      (set! message-timer (make-object timer% stop-message message-timeout)))
+    
+    (define (set-message msg)
+      (refresh-message-timer)
+      (set! message msg))
+    
+    (define (set-angles-message angle altitude)
+      (set-message (format "angle = ~a\naltitude = ~a"
+                           (number->string (round angle))
+                           (number->string (round altitude)))))
+    
+    (define (start-message msg)
+      (define refresh? (not (equal? msg message)))
+      (set-message msg)
+      (when refresh? (refresh)))
+    
+    (define dragged? #f)
+    (define (start-click-message)
+      (unless dragged?
+        (start-message "Click and drag to rotate")))
     
     (define/override (on-event dc x y editorx editory evt)
-      (case (send evt get-event-type)
+      (define evt-type (send evt get-event-type))
+      #;(when (not (eq? evt-type 'motion))
+        (printf "evt-type = ~v~n" evt-type))
+      #;(when (eq? evt-type 'motion)
+        (printf "motion for ~a; x,y = ~a,~a~n" (eq-hash-code this) (send evt get-x) (send evt get-y)))
+      (case evt-type
         [(left-down)  (worker-thread-wait rth)
                       (set! angle (new-angle))
                       (set! altitude (new-altitude))
+                      (set-angles-message angle altitude)
                       (set! left-click-x (send evt get-x))
                       (set! left-click-y (send evt get-y))
                       (set! left-drag-x left-click-x)
                       (set! left-drag-y left-click-y)
                       (set! draw? #t)
-                      (start-timer)]
-        [(left-up)    (stop-timer)
-                      (set! draw? #f)
-                      (worker-thread-wait rth)
-                      (set! left-drag-x (send evt get-x))
-                      (set! left-drag-y (send evt get-y))
-                      (set! angle (new-angle))
-                      (set! altitude (new-altitude))
-                      (set! left-click-x 0)
-                      (set! left-click-y 0)
-                      (set! left-drag-x 0)
-                      (set! left-drag-y 0)
-                      (worker-thread-put rth (draw-command #f angle altitude))
-                      (define new-bm (worker-thread-get rth))
-                      (when (is-a? new-bm bitmap%)
-                        (set! bm new-bm)
-                        (set-bitmap bm))]
-        [(motion)     (when timer
-                        (cond [(send evt get-left-down)
-                               (set! left-drag-x (send evt get-x))
-                               (set! left-drag-y (send evt get-y))
-                               (set! draw? #t)]))]))
+                      (start-update-timer)]
+        [(left-up)    (when update-timer
+                        (stop-update-timer)
+                        (set! draw? #f)
+                        (worker-thread-wait rth)
+                        (set! left-drag-x (send evt get-x))
+                        (set! left-drag-y (send evt get-y))
+                        (set! angle (new-angle))
+                        (set! altitude (new-altitude))
+                        (set-angles-message angle altitude)
+                        (set! left-click-x 0)
+                        (set! left-click-y 0)
+                        (set! left-drag-x 0)
+                        (set! left-drag-y 0)
+                        (worker-thread-put rth (draw-command #f angle altitude))
+                        (define new-bm (worker-thread-get rth))
+                        (when (is-a? new-bm bitmap%)
+                          (set! bm new-bm)
+                          (set-bitmap bm)))]
+        [(motion)     (when (and update-timer (send evt get-left-down))
+                        (when (not (and (= left-drag-x (send evt get-x))
+                                        (= left-drag-y (send evt get-y))))
+                          (set! left-drag-x (send evt get-x))
+                          (set! left-drag-y (send evt get-y))
+                          (set! draw? #t)
+                          (set! dragged? #t)))
+                      (when (and (not (send evt get-left-down))
+                                 (<= x (send evt get-x) (+ x width))
+                                 (<= y (send evt get-y) (+ y height)))
+                        (start-click-message))]))
     
-    (define/override (copy)
-      (make-object this%
-        make-bm angle altitude bm (worker-thread-send rth (copy-command))))
+    (define (draw-message dc dc-x-min dc-y-min)
+      (define pd (make-object plot-device% dc dc-x-min dc-y-min width height))
+      (send pd reset-drawing-params #f)
+      
+      (define lines (map (λ (line) (format " ~a " line)) (regexp-split "\n" message)))
+      
+      (define-values (_1 char-height baseline _2) (send pd get-text-extent (first lines)))
+      (define line-widths (map (λ (line) (send pd get-text-width line)) lines))
+      
+      (define box-x-size (apply max line-widths))
+      (define box-y-size (+ baseline (* (length lines) (+ char-height baseline))))
+      (define box-x-min (+ dc-x-min (* 1/2 (- width box-x-size))))
+      (define box-y-min (+ dc-y-min (* 1/2 (- height box-y-size))))
+      (define box-x-max (+ box-x-min box-x-size))
+      (define box-y-max (+ box-y-min box-y-size))
+      
+      (send pd set-alpha 2/3)
+      (send pd set-minor-pen)
+      (send pd draw-rect (vector (ivl box-x-min box-x-max) (ivl box-y-min box-y-max)))
+      
+      (send pd set-alpha 1)
+      (for ([line  (in-list lines)] [i  (in-naturals)])
+        (send pd draw-text
+              line (vector box-x-min (+ box-y-min baseline (* i (+ char-height baseline))))
+              'top-left #:outline? #t))
+      (send pd restore-drawing-params))
+    
+    (define/override (draw dc x y left top right bottom dx dy draw-caret)
+      ;(printf "drawing ~a~n" (current-milliseconds))
+      (super draw dc x y left top right bottom dx dy draw-caret)
+      ;(send dc draw-bitmap-section bm x y 0 0 width height)
+      (when message
+        (parameterize/group ([plot-parameters  saved-plot-parameters])
+          (draw-message dc x y))))
     
     (define cross-cursor (make-object cursor% 'cross))
     (define/override (adjust-cursor dc x y editorx editory evt) cross-cursor)
     
-    (send this set-flags (list* 'handles-events (send this get-flags)))))
+    (send this set-flags (list* 'handles-events 'handles-all-mouse-events (send this get-flags)))))
 
 ;; make-3d-plot-snip : (real real real -> bitmap) real real -> 3d-plot-snip%
-(define (make-3d-plot-snip make-bm angle altitude)
-  (make-object 3d-plot-snip% make-bm angle altitude))
+(define (make-3d-plot-snip make-bm angle altitude saved-plot-parameters)
+  (make-object 3d-plot-snip% make-bm angle altitude saved-plot-parameters))
diff --git a/collects/plot/plot3d/surface.rkt b/collects/plot/plot3d/surface.rkt
index 42c6f0fa4a..f5ea70358f 100644
--- a/collects/plot/plot3d/surface.rkt
+++ b/collects/plot/plot3d/surface.rkt
@@ -12,25 +12,16 @@
 (define ((surface3d-render-proc f samples color style line-color line-width line-style alpha label)
          area)
   (match-define (vector (ivl x-min x-max) (ivl y-min y-max) z-ivl) (send area get-bounds-rect))
-  (match-define (2d-sample xs ys zss fz-min fz-max) (f x-min x-max (animated-samples samples)
-                                                       y-min y-max (animated-samples samples)))
+  (define sample (f x-min x-max (animated-samples samples)
+                    y-min y-max (animated-samples samples)))
   
   (send area put-alpha alpha)
   (send area put-brush color style)
   (send area put-pen line-color line-width line-style)
-  (for ([ya  (in-list ys)]
-        [yb  (in-list (rest ys))]
-        [zs0  (in-vector zss)]
-        [zs1  (in-vector zss 1)]
-        #:when #t
-        [xa  (in-list xs)]
-        [xb  (in-list (rest xs))]
-        [z1  (in-vector zs0)]
-        [z2  (in-vector zs0 1)]
-        [z3  (in-vector zs1 1)]
-        [z4  (in-vector zs1)])
-    (send area put-polygon
-          (list (vector xa ya z1) (vector xb ya z2) (vector xb yb z3) (vector xa yb z4))))
+  (for-2d-sample
+   (xa xb ya yb z1 z2 z3 z4) sample
+   (send area put-polygon
+         (list (vector xa ya z1) (vector xb ya z2) (vector xb yb z3) (vector xa yb z4))))
   
   (cond [label  (rectangle-legend-entry label color style line-color line-width line-style)]
         [else   empty]))
diff --git a/collects/plot/scribblings/custom.scrbl b/collects/plot/scribblings/custom.scrbl
index 6990e3ba4f..b19dd6f1f7 100644
--- a/collects/plot/scribblings/custom.scrbl
+++ b/collects/plot/scribblings/custom.scrbl
@@ -2,6 +2,68 @@
 
 @(require "common.rkt")
 
-@title[#:tag "custom"]{Making Custom Plot Renderers}
+@title[#:tag "custom"]{Custom Plot Elements}
 
 @declare-exporting[plot/utils]
+
+@section{Plot Elements}
+
+@defstruct[plot-element ([bounds-rect  (or/c (vectorof ivl?) #f)]
+                         [bounds-fun   (or/c bounds-fun/c #f)]
+                         [ticks-fun    (or/c ticks-fun/c #f)])]{
+}
+
+@defstruct[(non-renderer plot-element) ()]{
+Examples: @racket[x-ticks], @racket[y-ticks], @racket[z-ticks], @racket[invisible-rect] and @racket[invisible-rect3d]
+}
+
+@subsection{Plot Element Bounds}
+                                                               
+@doc-apply[bounds-fun/c]{
+}
+
+@doc-apply[function-bounds-fun]
+@doc-apply[inverse-bounds-fun]
+@doc-apply[function-interval-bounds-fun]
+@doc-apply[inverse-interval-bounds-fun]
+@doc-apply[surface3d-bounds-fun]
+
+@subsection{Plot Element Ticks}
+
+@doc-apply[ticks-fun/c]{
+}
+
+@doc-apply[default-ticks-fun]{
+}
+
+@section{2D Renderers}
+
+@defstruct[(renderer2d plot-element) ([render-proc  (or/c ((is-a?/c 2d-plot-area%)
+                                                           . -> . (treeof legend-entry?))
+                                                          #f)])]{
+}
+
+@section{3D Renderers}
+
+@defstruct[(renderer3d plot-element) ([render-proc  (or/c ((is-a?/c 3d-plot-area%)
+                                                           . -> . (treeof legend-entry?))
+                                                          #f)])]{
+}
+
+@section{Legend Entries}
+
+@defstruct[legend-entry ([label string?]
+                         [draw ((is-a?/c plot-device%) real? real? real? real?
+                                                       . -> . void?)])]{
+}
+
+@doc-apply[line-legend-entry]
+@doc-apply[line-legend-entries]
+@doc-apply[rectangle-legend-entry]
+@doc-apply[rectangle-legend-entries]
+@doc-apply[interval-legend-entry]
+@doc-apply[interval-legend-entries]
+@doc-apply[point-legend-entry]
+@doc-apply[vector-field-legend-entry]
+
+todo: rename vector-field-legend-entry to arrow-legend-entry?
diff --git a/collects/plot/scribblings/todo.scrbl b/collects/plot/scribblings/todo.scrbl
index 0e739d70bd..c117d2ffab 100644
--- a/collects/plot/scribblings/todo.scrbl
+++ b/collects/plot/scribblings/todo.scrbl
@@ -11,9 +11,6 @@
         @item{2D kernel density estimator}
         @item{3D kernel density estimator}
         @item{3D decorations: labeled points, axes, grids}
-        @item{3D vector field}
-        @item{2D and 3D stacked histograms}
-        @item{2D grouped histograms}
        ]
  }
  @item{Possible minor enhancements
diff --git a/collects/plot/tests/isosurface-tests.rkt b/collects/plot/tests/isosurface-tests.rkt
index 930673454f..c50a1e62a0 100644
--- a/collects/plot/tests/isosurface-tests.rkt
+++ b/collects/plot/tests/isosurface-tests.rkt
@@ -1,6 +1,6 @@
 #lang racket
 
-(require plot plot/utils racket/flonum)
+(require plot plot/utils #;racket/flonum)
 
 (time
  (plot3d (isosurface3d (λ (x y z) (sqrt (+ (sqr x) (sqr y) (sqr z)))) 1
@@ -48,7 +48,10 @@
 (time
  (define (f1 θ ρ) (+ 1 (/ θ 2pi) (* 1/8 (sin (* 8 ρ)))))
  (define (f2 θ ρ) (+ (/ θ 2pi) (* 1/8 (sin (* 8 ρ)))))
- 
  (plot3d (list (polar3d f1 #:samples 41 #:color "navajowhite" #:line-style 'transparent #:alpha 2/3)
-               (polar3d f2 #:samples 41 #:color "navajowhite" #:line-style 'transparent #:alpha 2/3))
-         #:title "A Seashell" #:x-label #f #:y-label #f))
+               (polar3d f2 #:samples 41 #:color "navajowhite" #:line-style 'transparent #:alpha 2/3)
+               (parametric3d (λ (ρ) (3d-polar->3d-cartesian 0 ρ (f1 2pi ρ)))
+                             (* -1/2 pi) (* 1/2 pi)
+                             #:color "navajowhite" #:width 2)
+               (lines3d '(#(0 0 2) #(0 0 -2)) #:color "navajowhite" #:width 2))
+         #:title "A Seashell" #:x-label #f #:y-label #f #:angle 210 #:altitude 30))
diff --git a/collects/plot/tests/plot3d-tests.rkt b/collects/plot/tests/plot3d-tests.rkt
index 9d26ddb69b..418471d766 100644
--- a/collects/plot/tests/plot3d-tests.rkt
+++ b/collects/plot/tests/plot3d-tests.rkt
@@ -53,7 +53,7 @@
 
 (time
  (plot3d (stacked-histogram3d '(#(a a (1 1 1)) #(a b (1.5 3)) #(b b ()) #(b a (1/2)))
-                              #:labels '("Red" #f "Blue"))))
+                              #:labels '("Red" #f "Blue") #:alphas '(2/3))))
 
 (time
  (plot3d (surface3d + 0 10 0 1)