If you’re new to VisualCAMc, MecSoft’s cloud-based production CAM solution for Onshape, then you may not fully understand yet how your VisualCAMc toolpaths are associatively linked to your Onshape part model. In this blog, we’ll discuss the model associativity in more detail. We’ll also take you through the steps needed to update your machining operations automatically after making edits to your Onshape part.

The Need for Associativity

Consider this very typical scenario when you are working with Onshape and VisualCAMc.

  1. You load an Onshape Part Document into VisualCAMc and create machining operations.
  2. Subsequently, you modify the Onshape Part Document due to a design change.
  3. You then go to the VisualCAMc app to update your toolpaths.

In this scenario, you want to update the machining operations and toolpaths easily without having to start over. VisualCAMc handles this in the following ways:

Global Associativity

When VisualCAMc is invoked, it detects any changes that were made to the Onshape parent part. If changes are detected, VisualCAMc automatically replaces the older version with the modified version. In addition, all machining operations will be displayed in red text in the operation tree to indicate that they need regeneration.

Object Associativity

Onshape geometry objects such as edges and sketches can be utilized in creating one or more machining operations in VisualCAMc. For instance, in the case of a 2½ Axis Pocketing operation, a group of edges is selected to create the pocketing toolpath. When edits are made in Onshape, it is quite possible that the sketch defining the pocket was modified. VisualCAMc handles this case in a couple of different ways:

  1. A Non-Destructive Edit: If the object ID in Onshape is still the same, even though the underlying geometry has changed, VisualCAMc will continue to use this object but will recognize the new geometry. Using the 2½ Axis Pocketing operation example, if the dimensions for the length and/or width of the pocket have changed, VisualCAMc will propagate these changes to the pocketing toolpath automatically. Onshape dimensional edits fall into this category. The machining operation will be displayed in red text in the operation tree to indicate that it needs regeneration.
  2. A Destructive Edit: If the object ID in Onshape is changed, VisualCAMc will lose the association with the object and the regions will have to be re-selected before the machining operation can be regenerated. We call this a destructive edit. Using the 2½ Axis Pocketing operation example, here is a list of possible destructive edits:
    • The geometry feature is changed (a square pocket is now circular).
    • Additional geometry is introduced (a rectangular pocket now has fillets).
    • A new feature is added (a slot cuts through the pocket).
    • A sketch or feature is suppressed (the pocket is now removed).

Here again, the machining operation will be displayed in red text in the operation tree to indicate that it needs regeneration.

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Sample Exercise

Here are the basic steps needed to update the machining operations in VisualCAMc once part geometry changes have been made after machining operations are created. In the example below, changes made in Onshape are automatically propagated to the VisualCAMc toolpaths.

1. Load a part from Onshape into VisualCAMc and create your toolpaths. The sample part below has three toolpaths created (2½ Axis Facing, 2½ Axis Profiling and Hole Drilling).

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Original Onshape Part

VisualCAMc Part w/Facing Toolpath

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VisualCAMc Part w/Profiling Toolpath

Hole Drilling

2. Select the Part Studio tab to display your Onshape part.

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3. Right-click on an Onshape sketch and select Edit.

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4. Now select Top from the Onshape View Cube to see the sketch more clearly.

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5. Edit a few sketch dimensions and then select the checkmark to accept the sketch. We edited the coordinate location of all the holes as well as the outer perimeter dimensions.

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Current Onshape Sketch

Modified Onshape Sketch

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Select the checkmark icon in the sketch editor to accept and close the sketch.

6. The Part will rebuild. Now select the Isometric View icon from the Onshape View bar to display the Isometric View.

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Top View

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Isometric View

7. Now select the VisualCAMc tab and you will be informed that the part was reloaded due to geometry changes. The updated part geometry is loaded and displayed automatically.

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8. You will notice that all of your machining operations are flagged in red text to let you know that they need to be regenerated.

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9. Since the geometry changes modified the length and width of the part, let’s update our Part Bounds Stock. Double left-click on the Stock icon in the Machining Job tree to display the Part Bounds Stock dialog. From this dialog, pick the Calculate Geometry button and then pick the Save button. The new stock size will display on the part.

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10. Because our Stock dimensions have changed, we want to redefine the Work Zero to where we had it set in Step 1 when we started (Highest Z, South West corner of the stock model). Double-click on the Work Zero icon in the Machining Job to display the dialog.


11. From the Work Zero dialog, select Set to Stock Box, Highest Z and the South West and then pick Save. This places the Work Zero to where we had it before.


12. Because only non-destructive edits were made to the Onshape part, we can now proceed directly to regenerating our toolpath operations. Just right-click on the Machining Job and select Regenerate. All of our toolpaths are recalculated from the updated part.

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13. Selecting each operation from the Machining Job tree will display the updated toolpath based on the dimensional changes we made to the Onshape Part model.

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Revised Onshape Part

2½ Axis Facing Updated

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2½ Axis Profiling Updated

Drilling Toolpath Updated

14. Now we will select Save from the VisualCAMc main toolbar to save our CAM Data to the Onshape part document. You must Save your document to save your toolpaths.


Try It Yourself

If you want to learn more about the cloud-based VisualCAMc Milling plugin for Onshape, check out MecSoft’s Products page, Tech Blog or our YouTube Channel. To join the free VisualCAMc Beta program, go to the Onshape App Store and add VisualCAMc to your Onshape account. Enjoy!