Help! with CAM software

I’m trying to import a model from Rhino 6 to Aspire. I tried DXF, STL and Rhino 4D, neither is exact.
The machine is calibrated and when cutting a 2D shape it’s completely accurate; only having a problem with a 3D model. When cutting, the part is in the neighborhood of .05 off. Has anyone else had any experience with this software? Or is their a better, more accurate CAM software.

Any ideas or help will be appreciated.
Bob F.

Grizzly 1400mm x 1600mm 4axis A18 Chinese CNC

Attached is my System Info File
System Info.txt (2.2 KB)

Hi Bob - I have no idea about your target application but if, as it seems, you are exporting meshes, then getting an accurate mesh will be part of the workflow - see


This is a major problem with how Vcarve converts 3D models into heightmaps, and likely it’s not your meshing settings, but could be good to double check anyway. You just cannot do precise manufacturing with vcarve’s 3D milling. More about this discussion in a previous topic:

Hi Bob,

There could be multiple reasons for your issue.

Is the error on the X or Y, or the Z?

If you have only done 2D machining in the past and you are new to 3D machining, it could be something simple like not realizing you needed to change the tool between the roughing pass and finish pass. (check your machining strategy and tool specs)

I think we need a few more specifics to help you resolve this.

1 Like

Thanks for the reply. I’m having problems with X & Y. When importing to Aspire, the dimensions are not the same as the part in Rhino. X Rhino 7.29 vs X in Aspire 7.286, Y in Rhino 1.16 vs 1.155. However the actual part dimensions when cut are X is 7.39 and Y is 1.15. Also a rectangle X=7.29 and Y=1.16 drawn around the part is larger in both the X & Y directions than the imported 3D model.

Rhino file attached

Classical Bridge.3dm (1.9 MB)

Hi Pascal - Thanks for the reply. I read through the attached info. I think I’m having a problem with the two software talking to each other. I uploaded my Rhino file below to one of the other replies. Thanks again

Hi Siemen, Thanks for the reply. I uploaded my Rhino file below with the mesh settings. I may have to look around for another CAM program with a little more accuracy.

MeshCam and CamBam are quite good. Both have trial versions and otherwise are affordable.

Just for the record, I talk about Vcarve (instead of Aspire which you mention), but they’re essentially the same program with Aspire having a bit more features for editing of 3D models.

Increase the number of digits in Rhino and see if the Rhino dimensions agree with the Aspire dimensions. The difference currently looks like rounding in Rhino.

Have you checked that the cutting tool used is the same dimensions as the one in the CAM software?

Hi Bob,

Is the long dimension of the cut part actually 7.39 … that’s not a typo?
So that is about 0.1 difference from the correct dimension, in other words, its not proportional to the original?

Hi David & cdordoni,

Thanks for the replies. The dimensions I listed above are typed in correctly. I measured the bits I’m using and none are off over .001. I also rechecked the calibration of the machine. If a 4" diameter circle and a rectangle with the dimensions of 7.29" x 1.16" are drawn in Aspire all measure perfectly.

Another interesting thing, after downloading the trial version of Rhinocam, this software also sees the part as X=7.286 & Y=1.155.


If you change the absolute tolerance to 0.001" and the display precision to
001", (see below) the object actually measures X=7.286 Y=1.155 in Rhino.
You can’t go backward in the precision so just changing it now won’t make it match even if you increase the accuracy … You need to establish the precision in decimal places that you want from the start.

As far as the cut part dimensions at 7.39 x 1.15 … I don’t know.
“I also rechecked the calibration of the machine. If a 4” diameter circle and a rectangle with the dimensions of 7.29" x 1.16" are drawn in Aspire all measure perfectly."

It is possible that the 3D machining may be revealing an issue that the 2D cutting of your test pieces does not.

The many passes that are typical of removing material in 3d machining would compound any issues that might not be obvious in a simple 2D cut out.


Sure do appreciate you taking the time to figure out what I’m doing wrong. I spent the last hour redrawing my model with the correct precision settings. It now imports to Aspire with Z=.36, X=7.29 & Y=1.1608. With the next next machining, maybe it will turn out better.