Revolution/Polar Pattern issues

[leoheck]

I am using Freecad 0.19 and Part Design WB

I have a base feature that is created with the revolution tool (XZ plane)
Then, I subtract a sphere from its edge.
Then, I replicate that with a polar pattern using N replications (which is 22 right now)
My problem is that the polar pattern cant be applied. It could subtract only 5 spheres.

So, why this happens? Is it a bug? When I zoom in a lot in the sketch of the base feature, I see it is shifted 0.4 mm in Y axis. It looks like the revolutions is not totally centered. in Z-axis.

I don't know what to do to fix it. I tried to recreate everything from scratch but the same happens.

[chrisb]

Upload your file. It's almost impossible to help based solely on the textual description.

[leoheck]

I agree but I can't this time chrisb. I will try to recreate this issue on a simpler design to share here.

I am almost sure it is related to the B-splines. When I use them, the whole project behaves weird.
Sketching with B-splines is hard too. I can't constraint the curves together to move them freely.

[chrisb]

You may upload your file to a publicly available file hoster. Please use one without the need of registration for downloaders.

[Vincent B]

how can we help you without any picture or file?

[Rana]

Facing same issue with patterns.(both 0.18 and 0.19 FreeCAD).
File attached for reference.

[chrisb]

This seems to be an OCC issue: If I turn the seam of the first sketch, the pattern succeeds. Alas, the groove itself does not, so you may fiddle with this seam:

[chrisb]

Depending on the z-angle of Sketch I get quite different selections of repititions. 1,2,3, ... degrees deliver completely different results. 6 or 10 seems to be rather good, but that sure is not enough.

If I was searching for a random numbers generator I would be delighted.

[Rana]

You may be right about OCC issue.
Able to complete pattern with nano error (10 nm).Please find attached file.
Is there a way in FreeCAD / OCC coding that, if the calculation error is less than some threshold value(say :- less than 0.001 mm), it should follow topology ( merge points / surfaces ) instead of following calculation error.

[leoheck]

I was able to fix it somehow. I was having some issues like:

- Some days ago the subtractive revolution was not showing the red object which is subtracted. That makes the whole process hard. This feature looks good now.

- Also, the polar pattern was not making all of the copies I wanted. It was like the center of the polar pattern or the base feature was not aligned with the Z-axis.