Question: Does VoluMill control the tool's engagement angle with the material?
Not in the least. VoluMill toolpaths are based on a constant stepover. A constant-stepover toolpath, by definition, is not engagement-controlled. However, VoluMill does carefully adjust cutting feedrates to control the rate of material removal. When coupled with VoluMill's smooth, carefully controlled motion, you can get much higher material removal rates and better tool life than you are used to, with significantly less tool motion and cycle time than an engagement-controlled toolpath.