diff --git a/js/buttonbehaviors.js b/js/buttonbehaviors.js
index 1fce102..ff71a3d 100644
--- a/js/buttonbehaviors.js
+++ b/js/buttonbehaviors.js
@@ -306,7 +306,7 @@ function previewUp(redrawLess) {
     numLayers++;
   }
 //  redrawPreview(redrawLess);
-  redrawRenderedPreview();
+  redrawRenderedPreview(redrawLess);
 }
 function previewDown(redrawLess) {
   //    console.log("f:previewDown()");
@@ -314,7 +314,7 @@ function previewDown(redrawLess) {
     numLayers--;
   }
 //  redrawPreview(redrawLess);
-  redrawRenderedPreview();
+  redrawRenderedPreview(redrawLess);
 }
 function previewTwistLeft(redrawLess) {
   if (redrawLess == undefined) redrawLess = false;
@@ -323,7 +323,7 @@ function previewTwistLeft(redrawLess) {
   rStep -= twistIncrement;
   //        }
   //  redrawPreview(redrawLess);
-  redrawRenderedPreview();
+  redrawRenderedPreview(redrawLess);
 }
 function previewTwistRight(redrawLess) {
   //    console.log("f:previewTwistRight()");
@@ -331,7 +331,7 @@ function previewTwistRight(redrawLess) {
   rStep += twistIncrement;
   //        }
   //  redrawPreview(redrawLess);
-  redrawRenderedPreview();
+  redrawRenderedPreview(redrawLess);
 }
 
 
diff --git a/js/canvasDrawing_v01.js b/js/canvasDrawing_v01.js
index 4466bc9..0a6088f 100644
--- a/js/canvasDrawing_v01.js
+++ b/js/canvasDrawing_v01.js
@@ -325,15 +325,26 @@ function onCanvasMouseMove(e) {
 
   if (new Date().getTime() - prevRedrawTime > redrawInterval) {
     // redrawing the whole preview the first X points ensures that the doodleBounds is set well
+    prevRedrawTime = new Date().getTime();
     if (_points.length < 50) {
       redrawPreview();
     } else {
-//      redrawPreview();
       updatePreview(x, y, true);
+      /*
+       if (_points.length - prevUpdateFullPreview > prevUpdateFullPreviewInterval) {
+       console.log("f:onTouchMove >> passed prevUpdateFullPreviewInterval, updating full preview");
+       redrawPreview();
+       prevUpdateFullPreview = _points.length;
+       } else {
+       updatePreview(x, y, true);
+       }
+       //*/
+//      redrawPreview();
     }
-    prevRedrawTime = new Date().getTime();
   }
 }
+prevUpdateFullPreview = 0; // 0 is not a timeframe but refers to the _points array
+prevUpdateFullPreviewInterval = 25; // refers to number of points, not a timeframe
 
 function onCanvasMouseUp(e) {
   //    console.log("onmouseup");
@@ -414,13 +425,22 @@ function onCanvasTouchMove(e) {
       redrawPreview();
     } else {
       updatePreview(x, y, true);
+      /*
+      if (_points.length - prevUpdateFullPreview > prevUpdateFullPreviewInterval) {
+        console.log("f:onTouchMove >> passed prevUpdateFullPreviewInterval, updating full preview");
+        redrawPreview();
+        prevUpdateFullPreview = _points.length;
+      } else {
+        updatePreview(x, y, true);
+      }
+      //*/
     }
     prevRedrawTime = new Date().getTime();
   }
 }
 
 function onCanvasTouchEnd(e) {
-  //    console.log("ontouchend");
+  console.log("f:onCanvasTouchEnd()");
   console.log("doodleBounds: " + doodleBounds);
   console.log("doodleTransform: " + doodleTransform);
   //    ctx.stroke();
diff --git a/js/previewRendering_v02.js b/js/previewRendering_v02.js
index a85fc38..c09d954 100644
--- a/js/previewRendering_v02.js
+++ b/js/previewRendering_v02.js
@@ -203,7 +203,8 @@ function renderToImageDataPreview() {
 
 // called by the move up/down or twist left/right buttons
 // it is assumed that the preview has been rendered to an Image object, which will be used to draw the preview with (much better performance)
-function redrawRenderedPreview() {
+function redrawRenderedPreview(redrawLess) {
+  if (redrawLess == undefined) redrawLess = false;
   console.log("f:redrawRenderedPreview()");
 
   previewCtx.clearRect(0, 0, preview.width, preview.height);
@@ -221,6 +222,11 @@ function redrawRenderedPreview() {
       previewCtx.globalAlpha = globalAlpha;
     }
 
+    if (redrawLess && i%2 != 0 && !(i == 0 || i == Math.floor(numLayers/2) || i == numLayers-1) ) {
+      y -= yStep;
+      r += rStep;
+      continue;
+    }
     previewCtx.save();
 
     previewCtx.translate(layerCX,layerOffsetY+layerCY+y);