introduce script to generate assembly animation. still needs cleanup

rack/assembly/attachXYTrays.scad

@@ -0,0 +1,36 @@
+include <./common.scad>
+use <./attachSideConnectorModulesToYBars.scad>
+use <./propUpBottomXYTraywithSideWalls.scad>
+
+$vpt = [71,123,88];
+$vpr = [44,0,47];
+$vpd = 450;
+$vpf = 22.50;
+
+attachXYTrays(at=$t);
+
+module attachXYTrays(at=0,r=0) {
+
+  t1 = lerp(a=12, b=0, t=min(1, 2*at));
+  t2 = lerp(a=16, b=0, t=max(0, 2*at - 1));
+
+  module singleScrew() {
+    translate(v = [mainRailSlideHexOnYBarDx, mainRailSlideHexOnYBarDy, -5])
+      rotate(a=[-45,0,0])
+        translate(v=[0,0,14 + t2]) // length of caseScrewB
+      caseScrewA();
+  }
+
+  translate(v=[0,0,t1])
+    multmatrix(upperXYTrayTrans) {
+      attachSideConnectorModulesToYBars(at=1);
+
+      if (at >= 1/2) {
+        mirrorAllTrayCornersFromYBarSpace()
+        multmatrix(yBarMainRailConnectorTrans)
+          singleScrew();
+      }
+    }
+
+  propUpBottomXYTraywithSideWalls(at=1,r=r);
+}