https://pickypikachu.tumblr.com/post/115349063983/how-to-make-stuff-base-game-compatible-with-s4s

How to make stuff base game compatible with S4S

1. You must own the EP/SP/GP you want to make BGC stuff from.
2. First open S4S, and choose “Create 3D Mesh” and then click the giant “CAS” button.
3. Find your item, select all the colors, then click “Next”
4. A box will pop up asking you to save the package, name it and click save.
5. When S4S loads, click save again just to be safe.