Yeah, you really gotta learn EVERYTHING in order to make a 3D game in GM these days <__<
Them getting rid of the d3d_draw_shape functions and forcing you to set up a vertex format, construct a static vertex buffer etc makes it like 100 times harder than it used to be in the GM6/8 days... and most of the lightning/fog stuff is broken so you need to learn shaders as well if you wanna make things look good...