# Slide effect in voxel collisions

I'm making a voxel engine, and I'm trying to figure out the right way to make efficient collisions with a slide response (making the player slide against the wall).

Currently my collisions are pretty simple : if, after update, the player bounding box collides with the voxel world, then we just cancel the collision.

I have seen this answer on SO, but I don't understand what the answerer means here. Since a voxel is a single unit, how can I compute its normal ? Should I map the 3x3x3 block surrounding the voxel to a precomputed normal ?

• Take the unit surface normal of the colliding voxel (pointing outward).