Weird welding/subtract issue in 0.9.09

weld.lbrn (3.9 KB)

I’m running into a weird problem trying to combine some objects with welding and subtraction. I started from a fresh file and was able to duplicate it.

  • Create large square.
  • Create small square.
  • Copy/Paste to duplicate the small squares
  • V-center and align on each side the small squares and the larger one.
  • Select all and weld, select each small + large and weld, select large and each small and subtract, and select each small and large and subtract all have the same result:
    –> the right side small box makes the expected cut. The left side doesn’t. If the two objects share an edge, its not consistent in whether the cut is generated.

Thanks for this. Can you also provide a picture of this. Might be a bit easier if we have a visual. (well, for me at least :wink: )

Create and select-all on the left. After clicking weld, on the right.

As an additional observation after generating the screen shots, the X/Y position changes very slightly after the weld operation.

I am able to duplicate the problem but have discovered that if one selects one small square, then the larger one and welds, then repeats the process for the other square, all is good. A bit of a strange development. If the two smaller squares are created independently (not copy/paste) the second square won’t weld to the larger one, even when selected individually and not Ctrl-A.

Equally peculiar is that if the first selected square is on the right side of the larger square, it fails to weld. I’ve now messed up my test piece sufficiently to be unable to weld to the right side at all.

I leave this in the hands of people better able to troubleshoot.

Any thoughts on this, @LightBurn/@Rick?

What you’re experiencing, I think, is normal. The linked video may help to understand Weld, ambiguities, and Boolean operations (you have created the situation detailed starting at 1:44):

After watching this, you will see that you created an ambiguity to the welding function. You need to use a Boolean. A Boolean is limited to two objects. Your smaller two squares must be grouped so they become one object. Then you will need to select the now two objects (your large square FIRST and the grouped smaller squares SECOND) and use the subtract Boolean.

Thanks, @Stroonzo. However, I’ve also tried with 2 of the 3 objects and also with grouping. Variations of the same result. The objects don’t join consistently.

@rojhan, I went so far as to download your file, open it, and test. I do not have inconsistent results. I made a video for you to see:

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