Setting minimum curve radius for machining


I’ve got a detailed contour map which we’re going to machine as a solid and then cover with lasercut veneer. The issue we have is that the laser will cut a much more detailed line than the CNC router. is there a way of modifying a 2D curve so that it has a minimum radius of say, 1mm. Then we can cut the veneer to match the lack of detail on the machined part.



Depending on how many curves you have, my manual procedure has been to offset the curve by the cutter radius (like the 1mm you mention above) to the outside (the cutter side) with _Corner=_Round. Then take the result and offset it back again towards the inside (in the direction of the original curve). You should end up with a result that has the min radius on all inside corners, but the outside corners remain sharp. I suppose this could be automated, but you still would need to choose the “outside” direction in most cases.

If you can tolerate both inside and outside corners being rounded, you should be able to just use _FilletCorners on the curve.

Cheers. The offset idea works for some of the simpler lines, but there’s some pretty knarly landscape here and it tends to split the more complex lines into separate curves due to kinks.

Yeah… Rhino’s offset function just isn’t all that reliable when it comes to offsetting very complex polylines. We’ve had a few posts on the subject. Problem is, I don’t know how to solve this type of issue with any other more reliable procedure…

Thanks anyway. I’ve found a solution using Powermill that generates a 3D model of the machined part. I can export that back into Rhino and take it apart to get the curves I need. Long-winded, but seemingly easier than modifying every individual (1400+) line in Rhino.

Yeah, that’s a pretty funny solution… Virtually mill the model with the correct radius cutter which will create the min radius inside corners and pull that back in to Rhino. Does the exported model from Powermill come in with arcs as inside corners? Usually machining simulations are mesh based, so you would have some very fine polylines…?

Have you looked at this?