Below is a link to a slide show with videos of the roughing and finishing passes, of a carving of terrain (where my sister lives in CA) in birch plywood. The new stepper drivers and grblHAL/Teensy4.1 controller (and the good MPCNC design) allow me to move the finishing bit at over 50mm/sec, even while doing a lot of moving up and down in Z. The roughing pass went even faster.
In Google Photos, click on the i with a circle around it to see captions of each photo and video… Feel free to leave comments or questions. LINK TO SLIDESHOW
I am not sure which aspects you are referring to. Did you look at the captions on the slide show linked above? If you ask specific questions, I will try to answer them. The whole process of designing such a carving takes me about a week, and each one has its own new issues. I hope to make an Instructable about it when I have it more dialled in.
