Hi Defonten, I don't think you have any errors in your objects, you're just running into filleting bugs especially for the case of fillets needing to be trimmed against each other.

You might try importing it into a different CAD program which has a more robust fillet engine like ViaCAD or OnShape.

To do it in MoI you'd have a better shot if some faces were combined together, like if this area here was just one face instead of many:



That then simplifies the fillet structure by quite a bit:




The filleter tends to have more problems if you've got small edges, like you've got here due to the segmentation in 2 directions coming close to each other:



I'll PM you back the model that has the larger faces in it so you can test filleting with that.

I made the larger faces by extracting those faces using Edit > Separate, then did an "untrim" (http://moi3d.com/forum/index.php?webtag=MOI&msg=444.4) by selecting all the edges of those faces and hitting delete to remove the trim boundaries and recover the full underlying surfaces, then joined the top edges of those to get back to the original generator curve for those extrusions, then ran the Rebuild command (http://moi3d.com/3.0/docs/moi_command_reference10.htm#rebuild) to fuse those segments together into a single segment curve, then extruded that into the one single face and used Edit > Trim to trim that against the edge curves of the main face followed by Edit > Join.

- Michael

Thanks a lot Michael, but could you pls clear this untrimming process up a bit more for me? I try to get rid of those edges and they're just won't be deleted. What am I doing wrong?

"You might try importing it into a different CAD program which has a more robust fillet engine like ViaCAD or OnShape."


I also had similar problem but also often running in some fillet issues mostly not wanting to
fillet at all not because of bad model but the fillet just don't want to do it's thing + it can be very slow.

When i saw how fillet works in Fusion360, it's just unbelievable what it can handle like "t-sections" or self intersections to name some.

I really hope that Fillet is on the priority list of Moi3D v4.0 - to make it way more robust and fast as possible.

Hi Defonten,

> Thanks a lot Michael, but could you pls clear this untrimming process up a bit more for me? I try to
> get rid of those edges and they're just won't be deleted. What am I doing wrong?

You're probably selecting just one edge and hitting delete - instead you have to select an entire trimming boundary and then push delete. A quick way to select the entire boundary is to select one edge and then use Ctrl+A for select all.

If you have a version of this file with your original curves in them you used to boolean against you can just copy/paste that over instead of doing the untrim.

- Michael