3D Mock-ups?

I’m still getting started too, but having spent a fair bit of time working on an older car and have become overly familiar with foam, automotive body filler, and especially… sandpaper.

For those of you with more experience how have approached building a material library/sense?

Jesse, I’ve also purchased the book, it’s picture heavy and one of my better purchases of the year.
Loved seeing the use of Lego blocks for building a mold box.