#more boolean wierdness
5 messages in this thread
While trying to create a boolean object out of mostly flat surfaces, I notice
that sometimes on the edges between two booleaned objects, a triangle will be
shaded funny, as if it were no longer flat with surrounding triangles. I also
notice that this happens less when I opt not to weld vertexes, but I still
cannot always prevent it. I understand in a polygon environment csg is
sometimes sketchy, but I was wondering if anyone knew if there was anything
more I could do to avoid this problem, and maybe correct it after it happens.
Thanks –
Kai.
Kai: you are probably aware of this, but always [HOLD] before doing boolean.
It's too easy to loose an object due to weird result. Anyway, if an object
lacks sufficient mesh complexity it can produce unpredictable results. Your
flat surfaces are probably very simple meshes. You might have to make them
somewhat tesselated (increasing the face count/complexity of the geometry).
Also, and this is strange… on one project I was simply unable to get a proper
boolean function on an object. So i moved the object to an other location and
repeated the boolean, and it came out fine!!!! Then moved the now ready object
back to where it belonged. Now that is strange, and I dont understand it, but
it worked. Jeffrey
<< While trying to create a boolean object out of mostly flat surfaces, I
notice that sometimes on the edges between two booleaned objects, a triangle
will be shaded funny, as if it were no longer flat with surrounding triangles.
I also notice that this happens less when I opt not to weld vertexes, but I
still cannot always prevent it. I understand in a polygon environment csg is
sometimes sketchy, but I was wondering if anyone knew if there was anything
more I could do to avoid this problem, and maybe correct it after it happens.
>>
Have you tried (with or w/o welding) removing all smoothing groups, then
Auto_smoothing with various angles ?
Have you tried tessellating before or after the Boolean Op. ?
Have you tried the Smooth.pxp routine that comes with Bones Pro ?
BILL
Kai,
Have you checked the smoothing groups in that area. The odd triangle could
have been assigned to a different group than its neighbors.
Also you should check the mesh seams in that area. You might have mismatched
vertices or unwelded vertices that confuse the auto-smooth routine. Try edoing
a Select/Face/Single and select each vertex in the area. You should be able to
highlight all vertices attached to a given vertex. If not, then you have
unwelded vertices.
Terry Gilbert
Forcade & Associates
PS sorry for the delay in this message. I just found this in my outbasket.
Hello, Kai.
Definitely check your smoothing groups. The suggestion to un-smooth the object
then Auto Smooth it again has often worked for me.
One result to watch out for when doing boolean functions are long sliver-like
faces. These are often the faces that produce strange smoothing or rendering
effects. Sometimes they are just extra faces that were not cleaned up well
enough during the boolean process. Use Select/Face/Single and highlight the
face in question. Select the [HOLD] button and then try deleting that face.
Re-render that region to see if a hole is left. If so, [FETCH] the original
scene.
You might also try doing an Surfaces/Normals/Object Unify to make sure all your
faces are facing the same direction. I've also had this play a role in some of
my boolean fixes.
I hope this helps,
Bob