Need help with STL height(s)

[pmagnuson]

Trying my first 3D carve with a STL file import.
I cannot find a way to eliminate the small step in the base of the carve shown in this picture.

My settings are (mm)
Stock thickness 12.7
In the model there is a flat model shape

and the STL file

scale to height is set to 8mm.

I have also tried with the STL model base height set to 0 and get the same result.

This is the Model 3d View.

All help greatly appreciated.

[WillAdams (William Adams (Carbide 3D))]

Upload the STL and .c2d file, or send them in to support@carbide3d.com

[Tod1d (Tod (with 1 'd'))]

3D toolpaths cut ON the vector, meaning the center of the tool cuts on the vector (purple), so it’s cutting a bit bigger than the boundary. If the roughing tool (red) is larger than the finishing tool (green), you’ll get that step.