3D collision is there already. I have used it, it is based on Sparky's collision from DBPro. Take a look at these commands:
https://www.appgamekit.com/documentation/Reference/3D.htm
Specifically you can use raycasting, spherecasting and spheresliding. I thought there was more than that but I guess I've managed well enough using those commands in the past. When bullet physics is implemented I imagine we will have a lot more tools to play with but I would guess we have a few months to wait for that.
Using AppGameKit V2 Tier 1