Trying to understand mathematically

[Kurt-Dekker]

For #2, yes, you’re feeding origin: and direction: into Raycast, telling it where to start and where to go.

Sin/Cos/Tan still work as expected. It’s just not necessary here because you’re not going from an angle (polar coordinates) to cartesian corodinates (x,y). You just HAVE a position and a direction and that’s all Raycast needs.

Side note: The various Raycast functions are HORRIBLY overloaded, so it’s always best to supply the names of the arguments for all arguments, just to keep you from inadvertently crossing wires, like crossing up origin and direction for instance. Look up named arguments for how to do that. The little bit of extra typing for horribly overloaded calls like that is well worth it, IMNSHO.

ALSO, there are three broad types of raycasting in Unity:

Raycasting, colliders, planes, Plane, etc:

Keeping a plain/terrain within the view frustrum

You can get rays from the camera at a given spot, so one approach is to cast rays from the camera corners and make sure they hit your terrain, or hit your terrain bounding box. To ignore screen pixel dimensions and just get the corner rays, this is the API you want: The nice part is that it doesn’t matter how your camera is set, how your field of view is set, etc., It just works. You can use this to raycast and hit physics on your ground using: asks “did I hit any collider in the scene?…