This one is driving me nuts. I am trying to split the attached model into a top and bottom half. I have tried using a line and boolean difference and also creating a cube over one half and againg trying a boolean difference. The item is showing as a solid - I cannot see what is going wrong. Can anyone help?

Many thanks,

Philip

Hi
this is your solid:it shows wrong surfaces



after deleting wrong part you obtain a joined surface,now you can cut and on top wiew you can see weird section
my suggestion is to rebuild correctely this section than revolve it



hope this helps:M

Hi Philip, it looks like maybe some of the existing edges that are right overlapping in the same area you are trying to cut may be making the intersection somewhat unclear.

Booleans and cutting operations can sometimes have difficulty if there is geometry that kind of slightly weaves in and out of the cutting surface.

It looks like doing a boolean with a line drawn off to the side divides faces where it should but does not end up cutting the object in half, but it should be possible to fix it by using Edit > Separate to break the faces of the two halves apart manually, I'll see if I can do that and post a result for you.

- Michael

Didn't see Mauro's post above when I posted the previous message - it looks like there may be some little fragmented edges in those areas that he shows, things like tiny edges in the area to be cut or possibly little tiny slivery faces can end up confusing booleans as well and make it hard for it to cleanly categorize different volumes.

- Michael

Thank you - that has pointed me in the right direction.

Regards,

Philip

A couple of areas were a little off center from some previous operations:





That slight misalignment has created some little slivery areas, like here's a fragment of one little shelf like surface that sticks out a little bit off center on both sides:



The spot where that little slivery shelf crosses over from one side to the other at the top and bottom probably ends up as self-intersecting geometry and will confuse volumetric calculations.

You probably will need to reconstruct this object to avoid these little fragment areas, it may be best to revolve the whole thing from one profile.


- Michael

Let me know if you still need help - you can also get some construction curves by drawing in a plane through it and using Construct > Curve> Isect to generate intersection curves and then use those as a basis for preparing the revolve profile. There are some areas that need to be cleaned up before doing the revolve, zoom in to the juncture areas and you'll see some little fragmented areas in the intersection result coming from those little shelf pieces, you'll need to tune up those spots before doing the revolve.

- Michael

Micahel,

Thank you very much for your help. The Construct > Curve> Isect worked like a dream and I just had to pull some points around to get it sorted. It is amazing how tiny little errors can cause a problem but I guess with such brilliant tools available there is no excuse for being inaccurate.

Kind regards,

Philip