3D Slice reverse layer order for sinking?

3D Slice seems to follow a process that doesn’t work for sinking. Example: I have a white-high black-low image. When I send this to the laser, it excavates around the image, removing material from the top down. It leaves a nice positive image.

If I invert the image (doing so in the image attributes seems to also set the flag in the 3D Slice dialog) then it does excavate in reverse, but it runs the layers in the same order, so layer 1 is the topmost layer, and layer two is the next step down. This ends up obliterating much of the detail and makes everything sort of uniformly washed out.

It’s the difference between stacking pieces of paper, large to small, to make a cone, and adding layers of cling wrap, smallest to largest, to make a cone. You’ll just end up with a dome of wrap.

So I can use an image file to effectively make a coin, but not a coin die.

I’m wondering if there’s some option I’m missing to reverse the order in which the layers are burned, if I need to invert the image outside of Lightburn, or if this is unintended behavior. It’s not impossible to separate different depths into different files, but I’d like to avoid the additional work if there’s a setting I can toggle.

There isn’t at the moment, no. The code doesn’t actually generate a negated image anywhere when slicing - The new resampling code produces a single scanline at a time, thresholded by the current pass threshold, and just inverts the result if necessary.

I’ll have to make the higher-level code that runs the passes run them in reverse if the negative option is ticked.

This is done and should be in the 2.1 release.

3 Likes