Boolean difference Issues

I am currently running rhino 6 and am having an issue with boolean difference. The model being subtracted from is under going a deformaion with I do the difference. All objects are solid polysurfavces. I ave no idea what is going on. Anybody have an idea whats happening here?

Please post your rhino file.

Hi Sam -

That’s only the display mesh that is getting wonky. Use the DivideAlongCreases command to split the single surface into a polysurface at the kinks.

1 Like

Hello Sam,

If you do not mind would you please post the file (given you still have it) with the problem even though Wim provided the reason and solution. This way I and perhaps others could learn from this situation in a concrete way.

Thank you,


thank you for the post. I am trying to work thses solutions. I have never used the DivideAlongCreases command and am trying to figure it out. I do think that its more than the display mesh becase when I import the file into CAM software there is still some deformation in that area. But… it is different from the deformation I see in rhino. Ive included a model in the thread and if you have time to look I would highly value your opinion.

wonky file.3dm (426.4 KB)
Heres the file guys. Any solution is gladly welcome. Mahalo Nui for any help

Hi Sam -

I see that you are working in Rhino 6 and that DivideAlongCreases doesn’t work on that object in that version. This has since been fixed.

In Rhino 6, you can manually split that surface at the kinks by drawing lines between the knots and using those to split it.


So the typical split command is all that is needed? And I guess just rejoin after?

That’s correct, yes.