What is wrong with the Boolean Modifier ?

I’m trying to cut that grid along the shape defined by that ellipse but I can’t find 1 single working solution, I also don’t understand what is the problem with the boolean modifier in this case.

Someone else got this working ? I checked everything, normals, faces and duplicate vertices, i don’t know what to do .

http://www.sendspace.com/file/pfv41k

It gives up creating loops in a non-closed, self-inersecting mesh, i think. Just two adjacent links (those parallel to X) kill Boolean for good. It doesn’t happen if I cap holes or move them so they don’t intersect.

Default Grid, scaled by 2 and Elipse (scaled Sphere) and (scaled Cylinder) Boolean differences.


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It’s dirty, needs heavy manual cleaning to use, but works.
Your uploaded file has errors here - does not open.

Can you upload an example ? I have tried different meshes with the same shape, I would like to know what you mean with this.

According to my experiments the problem is the grid-like object and not the ellipse, I can cut other shapes with my ellipse, the problem is how to deal with the grid.

When I tried to open your file, it spat out a bazillion of errors. When loaded, all it said was “Cannot execute boolean operation”. Then I armed myself with a fail-proof scientific WAG method and started decomposing your grid. First I excluded all Y bars and found out that Boolean digested them nicely. Then I started dividing the array of X links into halves. All parts were disappearing after I used Boolean on them. Then I started joining pairs of links.


Et voilà, “Cannot execute boolean operation”!
What I found suspicious in this fragment’s topology was that it had non-capped ends and the links were intersecting. First I tried capping ends.


And it helped :slight_smile: Then I moved the links so they didn’t intersect.


Worked as well. From this I can conclude that Boolean is just too selective and can’t compute loops correctly in complex meshes.

Managed to get file downloaded.
You’re right, that’s a grid’s mesh what’s causing problem.
This cuts just fine. Triangles are hard to cut and one pat of your grid consists of separate segments.