I am new to Blender 3d,i try to use boolean modifier to cut model,but a un except error happened there is a circle on the "ExampleR", why after i use the boolean modifier,the "ExampleR" disappear? if i use "exact" instead of "fast",it works but it take a long time enter image description here enter image description here

Boolean Error

another example works correct enter image description here

the error example can be got here https://gofile.io/d/wCphqq

the result i want like that enter image description here

the selected verts is where the curve intersects with the model

  • $\begingroup$ docs.blender.org/manual/en/latest/modeling/modifiers/generate/… $\endgroup$
    – vklidu
    Jan 6 at 9:21
  • $\begingroup$ If you need a cut it is better use Bisect Tool $\endgroup$
    – vklidu
    Jan 6 at 9:55
  • $\begingroup$ @vklidu o thank you for you suggestion, I got a new way to cut. But But what I actually want to do is to use this curve to determine an irregular surface and cut it. Bisect Tool looks like he can only achieve flat cutting. My current plan is to use Boolean modifiers to add curve boundaries to the model, and then use scripts to delete the vertices that need to be deleted $\endgroup$ Jan 8 at 7:49
  • $\begingroup$ Probably would be helpful if you can ad mockup screen of desired result and share your blend to check it closer what you are dealing with ... $\endgroup$
    – vklidu
    Jan 8 at 8:21
  • $\begingroup$ @vklidu I upload my file an show my desired result at the end $\endgroup$ Jan 8 at 9:58

1 Answer 1


There is not too match to say ... I think all is described in my first comment link ...

  • Fast is simpler math that fails on such topology (like yours) with a small parts, even more in your case where the curve overlaps (you can see in your last image)

enter image description here

  • Exact is more complicated math for precise result and takes time co calculate

There is not to much options ... Knife Project partly worked for me (with cut through enabled), but it generates other cuts in projection trajectory. So not the perfect solution as well.


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