Ships are 3D so why not asteroids and debris. This is my take on these obstacles. I attempted to make the debris look kind of like the debris on the tokens. I took some artistic license because I limited myself to destroying four ships for six tokens. I decided to place the pic of the token on the bases so that in game play you could see where the path of the token was just like a regular token. All asteroids and debris models are magnetized so the can be removed if a ship needs to play through the path. Below is a the list of items used. I do not take credit for the originality of these ideas. Others have done similar projects.
Asteroids:
Great Stuff Insulating Foam
Airbrushed with acrylics
Debris:
Ships: X-Wing, B-Wing, Tie Bomber, Tie Fighter
Piano wire
Black Acrylic Paint
Lighter
Bases and stands:
1/8 inch black acrylic (cut with a scroll saw and sanded with a dremel to match game tokens)
1/8 inch clear acrylic rod
1/8 x 1/8 cylinder magnet in base
1/8 x 1/16 cylinder magnet glued to acrylic rod