In the attached, I have a polysurface, a closed curve and two open curves.
If I extrude the closed curve to the red line, boolean union on the two polysurfaces fails.
If I extrude the closed curve to the green line, boolean union on the two polysurfaces succeed.
This seemed odd, so I share.
Problem Union 2.3dm.zip (115.8 KB)
Hello- thanks, I see that - in general faces that are coincident can be unreliable in Boolean operations, just a fact of Rhino life. In this case the top face of the donut and the outer fillet are a single surface - DivideAlongCreases >SplitAtTangents=Yes will sort that out. In addition, and this is probably more the bug here - even though the remaining top face is planar, the intersection to the top plane of the boxy object is not clean - this case is generally handled but may - my guess - be compromised by the donut top face being a revolved surface and not a trimmed plane. If you remove that face and Cap the object (fills with a trimmed plane) , the Boolean works. I’ll get this on the pile…
Actually once divided, if you rotate the donut a little the Boolean will also work, rather than the Cap trick - the knot line moves so allow the intersection to work more cleanly - I guess that is the more specific bug.
Extra line:
-Pascal
Here is another example for your development pile on the same them.
I divided along crease (but did not rotate)
Problem Union 3.3dm.zip (86.6 KB)
(I previously reported similar on capping)
Boolean Union creates a bad surface.
ExtractBadSrf
Cap
And you are back in business…until
MergeAllCoPlanarFaces - creates a bad surface
ExtractBadSrf
Cap
And you are back in business.
Got it, thanks.
This all seems to work as expected in V8.
-Pascal
