Creating inlays

[jbraun]

This is just me mucking around to see what’s possible. My methods work in some designs and sizes and go very wrong in other cases. Camotics is recommended and also watching some back plots in f-engrave to see that software’s approach.
How the v-carved outline was done:

Assuming inkscape is displaying stroke with no fill.
In inkscape preferences change behaviour-steps-inset/outset to the desired face width
Make a duplicate of the current path.
Apply Path → Inset
Select the outside path and apply a black fill.
Ctrl + A to select all.
Path → Difference.
Save the file as an Inkscape SVG.
In Draft select both outer+inner path then 2 modification downgrades.

Attached is an example, zipped in case a svg isn’t accepted.
I’ve also kept a bit of a diary. Be warned it’s a hot mess created while learning (and finding easier ways) but it may contain something useful.
https://steppingintocnc.blogspot.com/

Lol I’m so slow Russ4262 posted in front. Hope this doesn’t double post.
xmas_tree_inlay.zip (3.74 KB)

[ianj001]

Any thoughts on what I might be doing wrong? - I have created inlays with Fusion 360 and F-Engrave in the past and wanted to do the same in FreeCAD but I am not able to get female part to look right.

I suspect you’re trying to do something that we just can’t do yet. Remember, this is a v-carve operation, not an inlay operation. It calculates a voronoi diagram to try to find a midline through a polygon. So the calculated toolpath is going to try to run the V-shaped cutter down the middle of the tree and down the middle of each ‘branch’. This is almost certainly not what you want.

For a true inlay, you need to cut the ‘pocket’. So you want to profile the inside shape with a v-cutter to give a slanted wall. You then want to clean out any acute angle points by raising the v-bit like a v-carve would. For the inlay piece, you’d do something similar but on the ‘outside’

If your inlay pocket and shape don’t have any angles that a cylindrical cutter can’t reach, you might be able to do this with current tools but not using vcarve at all. But you’d have to do some manual figuring.

Thanks Brad, you are absolutely right, it is creating a median line through the face. So it is working correctly it just doesn’t do what I had hoped it was going to do. Thanks for clarifying that for me.

[ianj001]

This is just me mucking around to see what’s possible. My methods work in some designs and sizes and go very wrong in other cases. Camotics is recommended and also watching some back plots in f-engrave to see that software’s approach.
How the v-carved outline was done:

Assuming inkscape is displaying stroke with no fill.
In inkscape preferences change behaviour-steps-inset/outset to the desired face width
Make a duplicate of the current path.
Apply Path → Inset
Select the outside path and apply a black fill.
Ctrl + A to select all.
Path → Difference.
Save the file as an Inkscape SVG.
In Draft select both outer+inner path then 2 modification downgrades.

Attached is an example, zipped in case a svg isn’t accepted.
I’ve also kept a bit of a diary. Be warned it’s a hot mess created while learning (and finding easier ways) but it may contain something useful.
https://steppingintocnc.blogspot.com/

Lol I’m so slow Russ4262 posted in front. Hope this doesn’t double post.

Thanks, I have done this in F-Engrave (great no nonsense app) and Fusion 360. I understand it is a difficult thing to do without the tools to do it. I appreciate you sharing what you have so far.

[ianj001]

… For a true inlay, you need to cut the ‘pocket’. So you want to profile the inside shape with a v-cutter to give a slanted wall. You then want to clean out any acute angle points by raising the v-bit like a v-carve would. For the inlay piece, you’d do something similar but on the ‘outside’ …

I have a macro(very, very slow) that is producing edges for this. I recently completed an alpha version of a sorting algorithm to assemble the edges in cutting order.

The first attached image is a test wire. The image contains a face, a green/red v-carve path created with recent Path WB, and a black edge set produced with the macro I am developing. Both the v-carve and macro are set to same depth, but v-carve has an error on depth, apart from failing to produce an inlay path in this case. (I shared this image and some info with MLampert on Gitter a few days back.)

The macro can return the mid-line if need be, but the main purpose is for profiling with a v-bit. I might extend usage to profile with other bit shapes in the future. The tool shape used in each is the same. As you mentioned above, you can see a small area in the low spot that would need to be cleared with a regular Pocket op and appropriate bit.

For an inlay on this shape, the v-carve op is not usable; although, the v-carve op is usable on certain use cases. The macro produces the correct paths(edges to be converted to paths) for this shape.

The last two images just illustrate another test case with my macro. It is looking good! The macro is not finished. I hope to have it return the interior regions as faces that need regular clearing - sort of a rest milling return data. I am working to finish my 12x24 storage building so I can again gain access to my CNC router and test some of the code on real material.

Cheers,
Russell

It looks like you are making great progress. - The lines seem to be what would be needed. Please post when you have a “shareable” macro, I would love to give it a try.

[jbraun]

Thanks, I have done this in F-Engrave (great no nonsense app)

I’ve been using F-engrave for years with the plotting turned off. When this topic was posted I started to pay attention to how and why it works.
What I’ve done isn’t as cumbersome as it looks, unfortunately I can now predict pretty quickly where it’s going to fail

Russ4262
Need test pilots ? I’m good at breaking things.
ps/ You may already be aware of this and may be not relevant but anyway:
http://k40.scorchworks.com/Fengrave/f-engrave_calculations.htm

[sliptonic]

Thanks, I have done this in F-Engrave (great no nonsense app) …

I’ve used F-Engrave for years (still do). Scorch has done some amazing things with it and I respect him immensely. Both F-engrave and it’s sister G-codeRipper can do some things that Path still can’t do. That said, there is some nonsense, it’s just under the hood:

It’s a single python file (currently approaching 10000 lines) - which is super hard to comprehend.
The user-interface uses Tk which has been declining in popularity for twenty years.
The ui code and the application logic are tightly coupled so refactoring it would be difficult.
Scorch doesn’t maintain the code in a git repo so it’s almost impossible for anyone to contribute, either bugs or fixes.
Finally, It’s licensed GPL3 which limits code re-use by other more permissive software (FreeCAD).

I like the software but I really hope Scorch doesn’t go near any buses.

[ianj001]

Thanks, I have done this in F-Engrave (great no nonsense app) …

I’ve used F-Engrave for years (still do). Scorch has done some amazing things with it and I respect him immensely. Both F-engrave and it’s sister G-codeRipper can do some things that Path still can’t do. That said, there is some nonsense, it’s just under the hood:

It’s a single python file (currently approaching 10000 lines) - which is super hard to comprehend.
The user-interface uses Tk which has been declining in popularity for twenty years.
The ui code and the application logic are tightly coupled so refactoring it would be difficult.
Scorch doesn’t maintain the code in a git repo so it’s almost impossible for anyone to contribute, either bugs or fixes.
Finally, It’s licensed GPL3 which limits code re-use by other more permissive software (FreeCAD).

I like the software but I really hope Scorch doesn’t go near any buses.

I approached him to get the files it creates concatenated into one file with a tool change but he said it wasn’t possible. I created a fairly trivial separate python program to do the concatenation and insert the tool change so that it would work for me. - I like that it works but haven’t looked under the hood. It does take a little understanding.
I am looking forward to the time when FreeCAD can do this without too many tweaks. - I have seen great things happening with the software. I am really pleased I came back to it from Fusion 360.

[ianj001]

Thanks, I have done this in F-Engrave (great no nonsense app)

I’ve been using F-engrave for years with the plotting turned off. When this topic was posted I started to pay attention to how and why it works.
What I’ve done isn’t as cumbersome as it looks, unfortunately I can now predict pretty quickly where it’s going to fail

Russ4262
Need test pilots ? I’m good at breaking things.
ps/ You may already be aware of this and may be not relevant but anyway:
http://k40.scorchworks.com/Fengrave/f-engrave_calculations.htm

Thanks, I had looked at the math and some other folks papers on this. It is sufficiently complicated that I don’t think I can add to the solution but would be happy to try if someone else wants to see how it cuts.