Sure! I'm happy to go over it as often you'd like

Several ways:

• We will understand how the model works. For example, when we get to curves and surfaces, we will understand the mathematical behavior of the curve/surface.
• We can ask Threejs to calculate a particular point on a curve/surface, given its parameters, so we have to understand what they mean.

Will we ever need to calculate these by hand? No. That's what we have GPUs for.