Need offset for squish transition but causes boolean union failure

Offset is needed to form the 1mm thick transition area, but it doesnt then join to the pipe command ’ thick yes 1mm’ and the bottom squished solid formed from outer profile and offset 1mm then solid extrude.
I could understand that if the profiles curves were not tangent drawn .

offset causes boolean fail.3dm (351.0 KB)


The outer shell isn’t able to join.
So I dupborder the middle peace and did 2 new extrusions.
Joined the 3 peaces and did an 1mm offsetsrf with “volume” yes
offsetfail2.3dm (755.1 KB)

Hi Steve - if the outer surfaces are actually made tangent to the pipe all along its edges, top and bottom, the offset will behave as you expect. I’d forget about Booleans here, and work at the surface level.

offset causes boolean fail_PG.3dm (210.5 KB)


Hi @JayR,

Remaking the outer surface is the way to go. The three parts then join and the whole can be offset. I’d tweak your solution by keeping the two end sections and remake the merged surface between them - that way the accuracy of the ends is preserved rather than propagating the slight off-tolerance of the centre section.