Editing Vectors for machining?

Hello, I am working my way through this course and been impressed with the material so far. As I have gone through the toolpath chapter I was noticing that many of the simulations result in a fairly rough profile cut with a fair amount of facets (which translates to a ton of sanding in real life of course), and it is an issue I have run into in general, even when I edit nodes for max smoothness or rebuild curves, ect. I have tried both shooting for a minimum number of nodes, and for a absurdly high number to compensate for these, but was hoping you could provide some advice on how to best edit vectors of smooth machining with as little as sanding possible in finished profiles. Obviously the issue is not one with straight spans, but curved shapes such as when doing luthier type work or attempting flowing bezier curves as opposed to arches with 2-3 nodes.


Hi there, does this just appear in the simulations? Or when you actually cut a piece on the CNC? If it is just the simulations, try creating the model at a higher resolution, the facets are more than likely caused by the simulation using a low resolution. Note, it will not machine like this if you are machining vectors, it is just a visual representation on screen.

Hope this helps?

mrowan22 (author)  leighton.ashcroft8 months ago

Hi, thank you for the reply. I does not only appear in simulations, it translates to the machining in most cases. With a 3d model I turn the resolution way up and can address issues that way (it has a lot to do with number of pixels etc. for anyone interested there is some good stuff available on that), but the issue is specifically when profile cutting vectors with bezier curves where the number of nodes seems to impact the smoothness of the cut. I specifically run into this with guitar bodies, where I end up having to do a ton of sanding with a spindle sander to remove the facets. It's not the actual machine, which is a Shopbot PRS Alpha and I run high end Onsrud bits with the appropriate feed and speed. From everything I gather, it is a software problem related to nodes.

Not a problem. That's fair enough, just wanted to rule that out. If you want to send me an example, I'll take a look at it for you and try to offer a solution.

One common thing is if the curve you are machining is offset, it will contain a lot of nodes. You could also try using the "Spline Vectors" tool, which will reduce the number of nodes, which will hopefully mean less sanding! :)