I have been dealing with this for years, I finally figured it out! I use sprut 7 and have always had a problem with the simulation, sometimes it wouldnt show the toolpath simulation, it would run without showing where it cut into the stock, I finally discovered that selecting solid or 3d it would function as it should, just not if 5d was selected. What a Dunce!!!!

I knew I wasnt the sharpest tool in the box but this is ridiculous!

This should give a few of you a chuckle ha!