Collision effects controls First person camera movement to limit it, and does not allow exiting from 3d model boundaries.
We have 3 ways for collision.
Collision settings are available from View menu Collision options.
Custom collision
1. From View menu select Collision -> Custom
2. For each wall in the interior of 3D model select Material property named 3D Collision.
3. Custom Collision may slow down the scene movement, so make sure 3D collision is selected on Low poly models.
4. Better to have transparent boundaries of object created with separate material and with low polygons count.
Inside Object Box Collision
This method will generate invisible boundary box around 3D model and control camera movement within these boundaries
Outside Object Box Collision
This method will generate invisible boundary box around 3D model and control camera movement outside these boundaries