b3dCollisionZ

Returns Z world position of collision contact point (north-south coordinate, depth). Takes entity (entity handle), index (collision index 0 to count-1). Returns Z coordinate (world space, forward-back position). Gets collision[index].position.GetZ() from g_entityCollisions. Use for 3D positioning, depth effects, or spatial audio. Same behavior as b3dCollisionX but Z axis (north-south). Thread-safe, O(1), returns 0.0 if out of bounds.