Hi Michael. Thanks for the insights, always helpful. The font curves have been extruded so there should be adequate overlap. I looked at the vector letters a bit looking for something that could explain, but don't see anything. Flow can result in different results without changes to what is being flowed ? I've uploaded the .3dm file to google drive below.

https://drive.google.com/file/d/1ft0DPWiWj6PtQcIzxRYjSk-k0xyRsS5z/view?usp=share_link

Hi Sven,

re:
> Flow can result in difference results running without changes to what is being flowed ?

The flow result is dependent on where you click on the base surface and target surface.

If you click in different areas that can give different results.

You need to click near the corner of a surface but not quite exactly on the corner, a little bit along one edge as described here:
https://moi3d.com/4.0/docs/moi_command_reference8.htm#flow

Looking at the file I think the self-intersections are in the B letter here:



- Michael

And there's a little zig zag in the I that would be good to get rid of too:





- Michael

Hi Sven, try the boolean with this attached version, it should be ok now.

I edited the curves in those 3 spots, 2 on the "B" and that zig zag which is only on one I it seems?

- Michael

Wow. I now see how carefully one needs to look at these things. Thanks for showing the actual problem areas. Helps explain where the flow stopped working so that should have been the area where I started looking for problem. Learning. Thanks Michael

Sven