topic Re: SPHERE SHIFTING POLES WHEN USING BOOLEAN UNION in AutoCAD Forum

SPHERE SHIFTING POLES WHEN USING BOOLEAN UNION

Migsey_UK — Tue, 11 May 2021 09:37:53 GMT

Hi There,

I have just installed 2022 and I am seeing really bizarre things. I need to do a solid in the shape of half a pill. The idea is to import this solid in 3dsmax and apply precise UVW mapping. So in AutoCAD, I drew two spheres and a cylinder. I then used boolean subtract to get rid of half of them and then boolean union to join them all up. When I have the two hemispheres and the half-cylinder lined up both spheres are showing the poles facing up as they should. After uniting the three solids, the poles shift randomly. When I bring the solid into 3dsmax, although perfect in shape, faces are all shifted. The following two images illustrate the process.

This is the summary of the procedure in AutoCAD

1 - the three solids separate

2 - the three solids lined up

3 - the three solids joined u using the UNION command.

It is already noticeable that the hemisphere poles have moved from their original position.

In 3dsmax I have perfect geometry but the faces on the unified solid make the UVW mapping quite impossible in terms of precisely moving the vertices. Why is AutoCAD shifting the sphere poles?

I tried other workarounds such as drawing a quarter of a circle, make t a region and then revolve it to create the hemisphere. All goes well with poles always facing the expected way but after using the UNION command it all goes a bit pear-shaped, I mean, in terms of shape, geometry is perfect but faces are not where they were supposed to be. Any ideas as to why is AutoCAD doing this?

Many thanks

Importing thee three into 3dsmax I et the following

Re: SPHERE SHIFTING POLES WHEN USING BOOLEAN UNION

coffeejeanpaul — Fri, 28 May 2021 02:38:58 GMT

Hello

I see the issue.

Work around I did, is use half a circle then revolve it to the shape and then join it to the cylinder.

The face maintains its position.

See attached file

Hope this helps.

Re: SPHERE SHIFTING POLES WHEN USING BOOLEAN UNION

Migsey_UK — Fri, 28 May 2021 10:31:37 GMT

Thank you very much for looking into this. yes, I managed to get it done that way yes. Strange how I didn't try that approach before. In any case, after the triangulation and when it comes to UV mapping, to have the poles rotated 90 deg feels a bit strange. Still better than before ;-).

I wish someone from Autodesk would tell me why does AutoCAD behave like this. Is it a bug? Sadly I have an educational license and, as such, no support whatsoever from Autodesk in that sense. If anyone from Autodesk sees this post, let me just congratulate you for the WORST customer support I have ever seen. Every other educational license I have allows me to have full support from the makers of the software.

Once again, many thank you for your answer.