polyRoundExtrude with internal holes

[echo-bravo-yahoo]

Is there a way to use polyRoundExtrude on a polygon set with internal holes (e.g., a doughnut)?

If not, is there a way to achieve a similar effect of top+bottom chamfers (rounding X/Y/Z) and rounded edges (X/Y)? polyRound smooths in (X/Y), but then extruding it doesn't have a convient way to chamfer, and polyRoundExtrude can't take in the output of polyRound...

I may source-dive and cobble something together later, if I have the time...

[Irev-Dev]

Hey @Trial-In-Error,
Yeah it is supported in an indirect way, but I should probably document the intention better though.

polyRoundExtrude supports negative fillets, you have to then put on your normal OpenSCAD thinking hat and use difference with another polyRound like so.

radiiPoints=[[10,0,10],[26,20,1.1],[8,20,10],[0,7,0.3],[5,3,0.1],[-4,0,1]];
radiiPointsNegative=[[11,10,0],[15,15,1.1],[11,15,1.1]];
negativeFilletsForHole=-1.5;
extrudeHeight=2;
difference(){
    polyRoundExtrude(radiiPoints,extrudeHeight,0.5,0.5,fn=8);
    translate([0,0,-0.005])polyRoundExtrude(radiiPointsNegative,extrudeHeight+0.01,negativeFilletsForHole,negativeFilletsForHole,fn=8);
}

A big assumption under the hood with polyround is that you'll be making a ring/closed-loop. It might be possible to take that assumption out of the code, but it's pretty old code. if I were to do a re-write I would change a great many things

Does that help?

[echo-bravo-yahoo]

Absolutely! This helps immensely, thanks - I read the docs for negative fillets numerous times without putting together how to use it like this. An example in the docs would really help make this clear.