Blender: boolean union losing faces

Discussion in 'Software and Applications' started by dskloet, Aug 12, 2010.

  1. dskloet
    dskloet New Member

    I'm still trying to understand the basic operations in blender.
    I have two overlapping, triangulated, manifold meshes both with normals facing outward. But when I take their boolean union and delete the originals, one of the objects in the union has lost a bunch of faces on the backside making it non-manifold.

    Any idea why this might be happening?

    thanks in advance,
  2. bartv
    bartv New Member
    Blender's Boolean operator isn't too good (at least it wasn't in 2.49 - I haven't tried in 2.50 yet). At the very least, make sure both input models are manifold, and avoid coincident vertices and faces. Your mileage may vary though - Blender usually crashes when I try to use its Booleans..

  3. dskloet
    dskloet New Member
    I thought my manifolds weren't allowed to overlap so I wanted to take their boolean union. But I found out that I can just upload my model without joining my manifolds. Thanks.
  4. jasolo
    jasolo New Member
    I discovered that reducing the number of faces in the mesh also reduces the time of the boolean operation and so the probability of crashing (at least with version 2.49).

    That reduction can be done without changing our model. The solution is to "separate" in each mesh the faces belonging to the union/intersection area, and to make the boolean operation on those separated meshes. Finally, you can join those faces to the original meshes and do a "remove duplicated vertices".