Render Mesh Does Not Match Object Wireframe

User of 5 years, first time poster here.
I have noticed in some of my files that the view mesh (rendered/shaded surfaces) is misaligned from the wireframe.

In the case of the example image, the objects were created in this way: I modeled the building at 1:1 scale in real life. I then exported the model and scaled it down by 1/192 (which is 1’=1/16" architectural scale), so I could build a desktop-sized model of it. While working on the physical model with the smaller file I added some details, which I wanted to add back to the 1:1 scale model. I pasted the smaller model into the 1:1 file and scaled it up by x192 so that they are the same size, however the pasted model is having render mesh issues, while the original model is fine. This problem persists after moving both objects closer to the origin as well (within 200’ of the origin), which I read was helpful for some users. I did not have any render mesh issues with the smaller “model scale” file either.

-In the model scale file units are inches, with an abs tolerance of 0.001" (objects are 1/192nd size of the 1:1 scale file).
-In the 1:1 scale file units are feet, with an abs tolerance of .01’

I am assuming the problem is caused by the different tolerances in the two files of origin for these models, perhaps misalignment imperceptible in the small scale file are being exaggerated when I scale it up the match the 1:1 file? It is not a huge deal and the files are still workable (snaps, make2d etc work as expected) it is just a little annoying, although I suppose it would be a problem if I ever wanted to make a rendering that preserves the details from the smaller scale file. I was hoping someone could explain to me why this happens and maybe suggest a better way of moving between large scalar jumps in models? Is there a way I could set my tolerances up that would help to mitigate this issue perhaps?


Hello- scaling up by 192 will likely pull things out of tolerance - ExtractSrf the faces or Explode the objects that look incorrect and RebuildEdges, then Join - do they join back up as expeced? My guess is not…


Hi Pascal,

Thanks for getting back to me. Went ahead and tried your suggestion on a couple of objects, some join up fine to become solids again and others do not. The render mesh problems went away when I ran the RebuildEdges command, though. Rebuild edges tolerance is at the default 1e-05.
Another interesting note: I boolean union’d two copies of the same problematic solid together and that seemed to fix the display problems and created a closed solid polysurface, while RebuildEdges on the same surface returns an open polysurface.

Half octagon is open after RebuildEdges, whole octagon is closed after BooleanUnion of two identical halves, without exploding and rebuilding.

For this object, RebuildEdges worked fine.