Holes in model from height map

[bpedit (Byrne Pedit)]

This is my first attempt at producing a working test of 3D from a height map, I’ve perused several threads and the Carbide video to no avail.

I’ve created a jpeg image (also tried a png with same results):

I want to carve this into a 4.0 mm thick piece of substrate to a maximum depth of 2.0 mm (the black) leaving the white as unmilled surface. I placed the image into a rectangle, set the Height to 2.0 mm and Base Height to 0 mm.

After applying tool paths it appears:

The entire rectangle appears to be cut to a depth of 2.0 mm and there are mysterious “holes” through the material. (The cut about the rectangle is me experimenting with placing the height map into a form fitting SVG in place of the rectangle.)

If I change the Height to 4.0 mm and set a Base height of 2.0 mm:

Which simulates to:

This looks better with the flush surface but the holes are still there. WTH? (Heck.)
And the model 3D preview shows:

3D_test_1.c2d (672 KB)

[Chaotica (Joel McKenzie)]

Is this what you’re trying to get?

[bpedit (Byrne Pedit)]

It appears so though I can’t rotate to completely inspect. What’s the magic?

[Chaotica (Joel McKenzie)]

Add a rectangle vector & use it to make a flat base 4mm thick. Then subtract your height map components from it. Seemed to work better by using the Invert option in the component setup.

[bpedit (Byrne Pedit)]

I can make that work, thanks! Curious one would need this indirect step but it seem to work. One difference is I set the Base Height of the height maps to 0 versus, otherwise the edges drop down too far before flattening out…

I think I can test mill this now, thanks again.