Re: coloring model causes Z-fighting, depending on order
Yes all the negative objects are drawn and even though not visible in the final object can cause Z fighting. When you make complex assemblies it is impossible to ensure all the negative parts don't interact, so I always render a 3D difference or intersection. Because that is slow I avoid 3D difference as much as possible. For example, your blue shape could be a linear_extruded 2D difference and then it won't Z-fight and will be fast to draw.