View Full Version : Bad triangulation problems with CAD models

07-21-2009, 07:22 PM
Hi, I'm working on a project that's using some complex CAD models. We're converting them to .3ds, then pulling them into lightwave. The problem is they have some real ugly triangulation and they look terrible once you put smoothing on. Anyone have any tips on working with models like this?


07-21-2009, 07:29 PM
TBs untriple might help you
Almost half way down the page.
If that doesn't help you could do a search for trigon, another plugin to merge tris automaticly

07-22-2009, 12:28 AM
The .3DS format does not support quads, only tri's, so that could be your bottleneck.

Can you output via OBJ or FBX ? Which CAD application are you using?

(If you have Rhinoceros it saves to LWO directly, for example).

07-22-2009, 08:38 AM
If your CAD files are DWG, then my workflow for converting to LWO is:


The method I use is:

Load DWG file into ACME CAD Converter (http://www.dwgtool.com/cadconvert.htm) and export as AutoCAD R12 DXF

Load the resulting DXF file into AccuTrans3D (http://www.micromouse.ca/downloads.html) and export as a "LWO Huge" file.

Hope that helps.


07-22-2009, 10:17 AM
The CAD files are coming in from SolidWorks, I'll have to check what formats are available for export.

07-22-2009, 10:51 AM
If your CAD files are DWG, then my workflow for converting to LWO is:


Thanks for that Peter, these files are SLDASM and SLDPRT, which we've converted to igs. Aren't dwg 2d?

07-22-2009, 03:19 PM
Triangulation of solids is done completely by SolidWorks. This link
http://www.shapeways.com/tutorials/solidworksstltutorial gives instructions for controlling the number of triangles created for a mesh.

One way to export from SolidWorks is to export each part from an assembly to its own OBJ file. Use the "File -> Multi Open" menu command in AccuTrans 3D and read all the OBJ files for the assembly at one time. Each OBJ file will be placed on its own layer as the assembly is put back together again.


07-22-2009, 05:49 PM
The CAD files are coming in from SolidWorks, I'll have to check what formats are available for export.

If possible try to play with surface smoothing values in Surface Editor.

07-23-2009, 03:39 AM
If you can get the file into Rhino (30 day trial available) it has quite good control over the mesh smoothing. Unfortunately, as has been mentioned, it will be a triangulated mesh but you can increase the resolution to smooth out the mesh at the expense of display speed.

Personally, I have found that Rhino exports CAD formats better as OBJ's than LWO's. I used it a lot earlier in the year to convert various files from AutoCAD and SolidWorks to Lightwave. There isn't a one-click solution but you will probably find a sweet spot in the export options between mesh density and smoothing issues.

07-24-2009, 11:10 AM
After much wrestling with plugins (expired, extended licenses, etc) we finally exported an obj, and it was triangulated too. So while 3D Max may natively work with triangles, it looks like Solidworks is the ultimate source of the problem. We can't really spin our wheels on this issue any longer, so what we're doing is tweaking the smoothing angles, cutting the flat pieces off so the points aren't merged, and re-modeling the worst parts.

Thanks for all your input.

07-24-2009, 12:23 PM
I am converting stuff from CAD at work for past 3 years. Maybe I can help? Let me know on the Skype, I think remodelling is too much. :)

07-26-2009, 09:00 PM
Well thanks for the offer Tomek, I may take you up on it. Fortunately this project isn't for a photo-real animation, we're ultimately bringing these models into Flash and animating them with Papervision. So I can just Photoshop the bad parts of the UV maps, although it of course would be better if we didn't have to. The objects aren't really all that complicated for the most part.