When I make a model in an external editing software and import it into unity, my player can go through that model.
2 Answers
2You need to add a collider to the model. Select your Game Object then click at the menu Component → Physics → Collider. If you need help on which collider to chose feel free to ask.
Use colliders.
1. Your question (title) and description contradict each other. 2. Exclamation points do not help anyone. 3. You could get the answer in 10 secs of googling. [Check for coliders.][1] [1]: http://docs.unity3d.com/Documentation/Components/comp-DynamicsGroup.html
– Lovrenc