Wierd artifacts

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 From:  mickelsen
4199.1 
I am creating some simple 3D parts, starting with 2D outlines and then extruding them. I then cut some pockets in some of them using extrusion and boolean diff. Two of the parts show a funny triangular artifact on them. I've included the drawing so you can see them. They are best seen in the 3D window.
What are they and how can I get rid of them?
Thanks,
Mark

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 From:  Michael Gibson
4199.2 In reply to 4199.1 
Hi Mark, it kind of looks like the booleans got confused and squished together 2 vertices of the result or constructed an edge in the result reversed from what it is supposed to be.

I'll take a closer look.

- Michael
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 From:  Michael Gibson
4199.3 In reply to 4199.1 
Hi Mark, probably related to these 2 lines here being apart by such a small distance kind of skimming by each other:



Zooming in there, those lines are apart from each other by a distance of 0.0006
units:



This kind of situation with pieces skimming by each other by such a small amount can make things a whole lot more difficult for the booleans to make sense of, it's a lot better for things to either be exactly aligned with one another or to be pushing through each other by a somewhat larger distance than that.

- Michael

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 From:  Michael Gibson
4199.4 In reply to 4199.3 
Those lines also seem to be at a tiny angle to one another instead of going in the exact same direction.
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 From:  Michael Gibson
4199.5 In reply to 4199.1 
Hi Mark, I've attached a file with those pieces fixed up.

I turned on control points for your curves and used the Transform > Align command to make those 2 lines shown above to be trued up with one another, and that helped the boolean to be able to figure it out better.

Things that are just barely misaligned by a small amount tend to make things difficult for the booleans - it has to try to decide whether to intersect such things with each other and leave little cut pieces behind, or whether to try and fuse some things together.

- Michael

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