I was a little stumped by the terminology Cut Inside/Outside.

I was a little stumped by the terminology Cut Inside/Outside. Of course, it depends on the direction of the geometry, but I assume they are always forced one way or the other (CW/CCW) per op? My thoughts would be to combine the three op types into one with a direction specifier, then either centerline, offset left or offset right (or just -1, 0, 1 etc. as an offset - although stating it left or right would be more user-friendly).

My first thought when seeing “inside/outside” was that it found internal and external features only, but I don’t believe this the case.

LW4 uses the even/odd rule for closed paths and the xor rule to combine multiple objects in a single op. It ignores CW/CCW since that’s usually meaningless in SVG files, its primary format. inside means apply a negative offset to the combined closed path and outside means apply a positive offset.

If you’re using SVG files with solid infill then it ends up like this: inside is inside the infill and outside is outside the infill.

Inside and Outside are intuitive phrases for most people… -1, 0, 1 aren’t, and left and right have no meaning in closed paths, as Outside is always both the most left and most right in that case…

@CescoAiel Thanks for your feedback. , My point is in respect to the tool, not the geom. I think this is standard CAM convention, like G41/G42.

Most users are not aware of “standard” milling CAM conventions and gcode. Inside/Outside is much more intuitive.

@cprezzi Understood. My observation was really that I couldn’t get it to work on a 10mm square and that I thought the terminology meant “cut inside features” or “cut outside features” using some sort of FR.

Make sure your square is a closed polyline. I frequently see cases where DXF exporters convert closed paths to lots of individual line segments. I don’t know why DXF exporters tend to do that; it’s insane.

@Todd_Fleming Thanks Todd, in another post a few days back, I pasted the 10mm square project, I see the geom is stated in the project; there’s 4 lines that seem on the nail to me. The DXF came out of PEPS, the product I work on - its DXF exporter uses OpenDWG that’s used by a lot of CAM vendors. I must be missing something, but meanwhile I just offset my geom in the solid model to compensate for the tool radius to get it going. My concern is that either I’m being thick or there’s a bug.

4 lines: that’s the problem. You need to export it as a single closed polyline for LW to see it as a closed path.

@Todd_Fleming Thanks Todd, now I understand. Works from CorelDraw saved as R11, doesn’t from my app using the OpenDWG libs! In any case, I’m glad it works, thanks for the message.