in previous version, this has a perfect result. (although on an older Mac, this is done with a 2019 MacBook Pro - Mojave)

wim

Correction: I opened this in v3.2 and it gave the same error. must be something in the geometry then? can't find out what exactly...

At the end
Kill the piece of sphere
NetWork

Not sure if the surface from the network is the same than a sphere but that close fine the volume! :)

Thanks for the explanation Pilou but I was hoping for an explanation why this does not work. If I move the sphere 1 mm up, the problem is solved, so there must be some intersection or so which generates bad geometry. I made sure the seams were on the other side, so that can't be the problem.

I have a better solution! :)

Make a Boolean Merge! And kill volumes not wanted!
At the end the volume is a solid!

Michael will give you some explanations why the Boolean Diff don't works fine... ...

Hi wim, it's just a guess since it will take a lot of work to confirm but I think it's probably the positioning of the bottom sphere's "pole" right nearby (but maybe not quite precisely on?) the intersection between the surfaces:


When I use Construct > Curve > Isect to generate intersection curves and zoom in to that pole closely it seems that the intersection curves come close to it but don't quite hit it directly.

The local area right around the pole of a sphere is kind of a sensitive zone because one direction of the surface is collapsing down to a single point. That causes some kinds of degenerate conditions for things like derivative and normal calculations. There is stuff in place to try and deal with those but maybe if you're just at the right spot nearby it, it can still be problematic.

- Michael

Just took a look and can confirm this to be the case...

If you go to the front view and rotate the sphere, just a bit, to get that seam edge away from the other object, the boolean works fine...

Seam or not the seam that is the question! :)

Thank you all, it is clear to me now! it seams there was a seem problem anyway ;-)

wim

The Boolean had an issue, though it's been seamlessly steered towards a funny bone...

I seem to like that....

Although, i think my post was kindof misleading with the way i described it...

Michael DID give a description of what was causing the issue. It's NOT the seam edge.

I could "pole" the group to discover my mistake.

You could also rotate the spheres seam further into the base object and get good results too, so it's not really the "seam"...

But since we are making an avoidance move, i chose seam out, to get rid of the pesky rascal anyway....

Note to self.....

The more funny is that my solution of the Boolean Merge resolves all but you must make some manual clicks! :)
(2 in this special case)

That seems to indicate the code to pole what part to throw away, is where the issue lay...

(See what i did there!)

@BurrMan:

It's hard to explain puns to kleptomaniacs because they always take things literally.

¡¡ To be clear, I am NOT suggesting that anyone is a kleptomaniac !! (…its just a pun)

Lol, Mindset....

I DO want to have a good time and be light with everybody... but i also forget that i am in a multi national setting, and i don't always get my point across....

And google ruins it, because they have a thing called "translate", which is NOT a translator, but a simple and often incorrect word exchanger...

But i'v learned to live with it.... it causes me to Take things, literally!