diff --git a/modules/processes/mill/raster/3D b/modules/processes/mill/raster/3D
index 36bd5fb4c15132e8b382254eb4ee8421f0e477ec..34445fb612e0af99d5bda085965cdc3f46babff4 100644
--- a/modules/processes/mill/raster/3D
+++ b/modules/processes/mill/raster/3D
@@ -24,7 +24,7 @@ var name = 'mill raster 3D (incomplete)'
 // initialization
 //
 var init = function() {
-   mod.dia_in.value = 0.0156
+   mod.dia_in.value = 0.125
    mod.dia_mm.value = 25.4*parseFloat(mod.dia_in.value)
    mod.stepover.value = 0.5
    mod.error.value = 0.001
@@ -265,10 +265,14 @@ function calculate_path() {
    // call webworker
    //
    webworker.postMessage({
-      h:mod.height,w:mod.width,error:mod.error.value,
+      height:mod.height,width:mod.width,
+      error:mod.error.value,
       xmin:mod.xmin,xmax:mod.xmax,
       ymin:mod.ymin,ymax:mod.ymax,
       zmin:mod.zmin,zmax:mod.zmax,
+      diameter:mod.dia_mm.value,
+      stepover:mod.stepover.value,
+      mmunits: mod.mmunits,
       map:mod.map})
    }
 //
@@ -276,8 +280,8 @@ function calculate_path() {
 //
 function calculate_path_worker() {
    self.addEventListener('message',function(evt) {
-      var h = evt.data.h
-      var w = evt.data.w
+      var h = evt.data.height
+      var w = evt.data.width
       var error = evt.data.error
       var xmin = evt.data.xmin
       var xmax = evt.data.xmax
@@ -286,6 +290,10 @@ function calculate_path_worker() {
       var zmin = evt.data.zmin
       var zmax = evt.data.zmax
       var map = evt.data.map
+      var diameter = evt.data.diameter
+      var stepover = evt.data.stepover
+      var mmunits = evt.data.mmunits
+      var ystep = Math.floor(stepover*diameter*w/(mmunits*(xmax-xmin)))
       var path = [[]]
       //
       // loop over lines
@@ -335,7 +343,7 @@ function calculate_path_worker() {
          if (xcur == (w-1)) {
             if (dx == 1) {
                dx = 0
-               dy = -10
+               dy = -ystep
                }
             else {
                dx = -1
@@ -345,7 +353,7 @@ function calculate_path_worker() {
          else if (xcur == 0) {
             if (dx == -1) {
                dx = 0
-               dy = -10
+               dy = -ystep
                }
             else {
                dx = 1