Weird Intersection of Solids

I ran into this weirdness so I saved it. Boolean union failed on the blue and red solids. However, the blue and red solids intersect by a wide bit where intersect shows no intersection.

Problem (78.4 KB)

Hey @miano! All Boolean operations work great on my Mac. However I am running RH7 and I think there have been some improvements to booleans in RH7.


Yeah, all better in V7, this one. Thanks.


dear @miano
if you want to do it in Rhino 6
explode the red polysurface and _insertKnot 2x visually and close to the intersection.
then join the surfaces again.
inserting Knots will not geometrically change the surface (just add knots / CVs) - and it is the workarround to “help” Rhino find intersections.
you see the additional Isocurves / Knot in the screenshot.
result in attachted file

Problem Intersect.3dm (192.8 KB)
to get rid of the coplanar Faces use _MergeAllFaces
kind regards -tom

My immediately though was to change the purple to have a round end matching the red—and that worked.

I saved this because I thought it was odd behavior.

The objects with also union ok if you rotate the cylinder on its axis so that the seam falls outside the merge region first (e.g. 180 degrees).

Worth knowing when creating objects that will be merged that it helps if you place the seam out of the way (assuming you can anticipate where the merge will be). In the case of a cylinder the seam placement is dictated by where you click for the radius.