introduce script to generate assembly animation. still needs cleanup

rack/assembly/slideHexNutToFeet.scad

@@ -0,0 +1,31 @@
+include <./common.scad>
+
+$vpt = [75,-10,-14];
+$vpr = [74,0,120];
+$vpd = 300;
+$vpf = 22.50;
+
+slideHexNutToFeet(at=$t);
+
+module slideHexNutToFeet(at=0) {
+
+  t = lerp(a=8, b=0, t=at);
+
+  module slideNut() {
+    if (!screwMask) {
+      rotate(a = [0, 0, 90])
+        rotate(a = [90, 0, 0])
+          hexNut(rackFrameScrewType);
+    }
+  }
+
+  translate(v=[0,t,connectorBottomToScrew + 0.5]) // where does this come from again? slack?
+    slideNut();
+
+  translate(v=[stackConnectorDx,t,connectorBottomToScrew + 0.5]) // where does this come from again? slack?
+    slideNut();
+
+  if (!plasticMask) {
+    stackConnectorFeet();
+  }
+}