I am struggling with cutting out a shape on a hollowed out cone form. The two forms I am using are a solid cone and a cone that has been hollowed out (but still has some thickness). From what I have read, it seems like boolean doesnt work when an object is too thin and is recognized as a 2d shape rather than 3d. Is there any other modifier or function on blender that can be used to subtract a shape from another shape for 2d or very thin 3d forms?

it seems like i can only add 2 images atm.

Bottom of Cone 1 has been hollowed out, cone 2 is solid.

enter image description here

enter image description here

  • 1
    $\begingroup$ An image of what your objects look like would help us understand what you are trying to do. $\endgroup$
    – user1853
    Commented Feb 28, 2016 at 8:26

1 Answer 1


Boolean modifier works best with meshes whose Volume can be correctly calculated.

This means that the mesh must have some features:

  • Watertight
  • Manifold
  • No overlapping faces
  • No loose faces
  • Consistent normals
  • ...and many more

As long as you provide a "good" mesh, there should be no issue. Even if 2D meshes has no volume, so they actually don't fall in this category, the modifiers should be capable of giving a sort of result of their intersection, but you cannot expect a ready-to-use mesh.

In the provided example, the solution could be to apply the modifier and just delete the unwanted faces (they should be already selected):

enter image description here

or to use the Intersect tool in edit mode once joined the shapes in one object as shown below:

enter image description here

or even play with the modifiers options, hoping to get a lucky(+) strike

enter image description here

(+) We may consider that lucky because it was unexpected, as we always figure out the model as if it is a real object (e.g, a paper). The truth is that we have never experienced a 2D object at all, so we tend to apply the known rules that belongs to the 3D objects, while the software isn't.

Obiuvsly the methods shown above require an extra effort in cleaning the mesh after the operation or can't ensure good results always. That's why the Volume's way is preferrable and human-predictable: I would suggest to temporarily close your mesh ( then apply the modifier and remove the unwanted faces)

enter image description here

Or stacking up a Solidify modifier above the Boolean to give some thickness to the to-be-cutted mesh (if this kind of shape is suitable for your project).

enter image description here


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .