Issues with combining objects

[j.r.hodgson]

Attached is a simple project (extracted from a bigger one that I am having issues with).
There is one larger flatter object (a guitar fretboard as it happens), and three objects sticking through it (actually segments of what was one large object, a shape for a neck + fretboard).
If I try to do a combine (an intersect is what I want, but any combine seems to do the same thing) between the fretboard and the neck objects then the two outer ones work fine, but that one in the middle has a failure in the boolean operation).
Can anyway explain to me WHY that one fails? And what can I do to fix the issue?

[jhackney1972]

The numerous cuts in the "Shelf Nut, With Slots body, was causing the Combine issue. An observation, it would be best to work with Capture Design History on.  Model attached.

[j.r.hodgson]

Thanks

But as there is no issue when I try to combine the fretboard ("shelf nut...") with either of the two end objects, which encompass far more of those numerous cuts. So I don't really understand why they become an issue in that one case.

I usually work with history on, I only turned it off in this case because I had to when I cut and pasted those objects from the project where I actually designed them.

[laughingcreek]

I would expect these edges to be perfectly straight lines with no curvature to them-

instead they do have a very slight curvature to them. you can tell because they will except a curvature comb analyses.  (if they were straight you couldn't put a comb on them). the curvature is so slight though you can't see any combs even at full zoom.  curvature in this range is problematic for fusion mathematically, it's akin to a near tangent condition on edges when doing fillets.

these 2 faces specifically are causing the immediate problem here-

why doesn't it cause problems all up and down the neck?  you just got lucky.  but right here fusion can't resolve if those faces are touching, not touching, or overlapping with the combine body. 

in the attached I deleted these 2 faces to to the combine.

but this is a potential hard to find problem that will continue to lurk in your design and may pop it's head up later if you don't fix the underlying problem, which will be related to the specific way you made the fret board.  I would suggest fixing the underlying issue, which means redoing the fretboard.  can't help you there with out seeing how you did it..

[jhackney1972 · Accepted solution]

When I removed them, the combine intersect succeeded.  Try it for yourself.

[j.r.hodgson]

The original fretboard is not my design, I downloaded it, and I hadn't noted that because of the way it is implemented there is one parameter (distance of fret slot from edge of board) that if you set it to zero leaves a tiny little wall across half the slot (I should have paid more attention to the parameter description, it says to put in a positive number when you want no gap).
Then to try to get the intersect to work, after one of those "make sure there is clear overlap" (or words to that effect) messages I just extruded the sides outwards, not noticing that the extruded slots were narrower.
So basically in trying to fix one problem with the combine feature I created another (one which you get absolutely no guidance on from Fusion).
I've now changed the fretboard creation to produce an oversized fretboard that the neck profile cuts to size with an intersect and it's all good.

Thanks, you pointed me in the right direction to solve the issue.

These little things that are hard to spot (especially if you don't have experience of what breaks Fusion) can be incredibly frustrating. I've lost hours trying to get patches to work, in some cases I never really solved what was happening and went another way, but in others I finally got down to it being something almost but not quite coincident (I had to zoom in really close to spot it).