# BooleanDifference fails

Done this many times but for what ever reason I cannot get it to work on this ring shank.

Thank you in advance … Dannyno hole.3dm (374.1 KB)

Your shank isn’t a closed solid.
It’s a combination of surfaces some of which are Joined, others Grouped, that do not fit together cleanly.
As a result, the Intersection of the closed cylinder and the shank are not clean curves that can be used to Split the surfaces.

Clean up those surfaces so they Join into a closed, solid, polysurface, and your Boolean should work fine.

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Thank you John you just said what I thought was wrong. Will do my best to clean things up not too sure how to approach it but am always learning. Thank you again. Danny

Hi Danny,
Your grouping is overkill for me. I ungrouped everything as I saw no need for it…multiple nested groups IIRC.

Problem here with this top surface overlappng…and more down the side. Inside ring surface was okay.

Extract the top surface and from the front view Split at the top to remove the overlap.

Edges don`t align here on the sides

Nor here.

I split your ring into a Quadrant before this next step to save work. Duplicate this edge and then delete the surface above it. I have already deleted the one below.

The end does not align with the plane so turn points on for the edge you just duplicated…

…then in the left view project the end point to the cplane.

Loft away twice to recreate those two surfaces.

Join them all up.

Apply quad symmetry and join to give you a closed polysurface.

Boolean and done. HTH

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Perhaps you already know this, but the osnaps are your friend in a construction like this. If you expect your individual pieces to join together into a surface or solid you need to make sure that each piece really is adjacent to it’s neighbors, not just “sort of close”. The tolerance determines how close they need to be for joining, but a large tolerance will just result in joining pieces that really shouldn’t be into a bit of a mess. By building the second and subsequent pieces via snapping to points on the preceding pieces you can be sure that the snapped points are not only very close, they are actually exactly the same within the floating point accuracy of the computer. You also need to be sure you don’t accidentally double up on points where you really only want one.

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Sochin, Thank you very much for all of your details regarding where all the problems are.
As I had no idea of what to look for you have given me much new knowledge.
Thank you again … Danny

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