Garry's Mod Wiki


  Vector, Vector, number util.IntersectRayWithOBB( Vector rayStart, Vector rayDelta, Vector boxOrigin, Angle boxAngles, Vector boxMins, Vector boxMaxs )


Performs a Ray-OBB (Orientated Bounding Box) intersection and returns position, normal and the fraction if there was an intersection.


1 Vector rayStart
Origin or start position of the ray.
2 Vector rayDelta
The ray vector itself, the ray end point relative to the start point. Can be implemented as direction * distance

Note that in this implementation, the ray is not infinite - it's only a segment.

3 Vector boxOrigin
The center of the box.
4 Angle boxAngles
The angle of the box.
5 Vector boxMins
The min position of the box.
6 Vector boxMaxs
The max position of the box.


1 Vector
Hit position, nil if not hit.
2 Vector
Normal/direction vector, nil if not hit.
3 number
Fraction of trace used, nil if not hit.


Simple example showing example usage of the function with visualization. Enter developer 1 into the in-game console, and look at any entity. Will display a red box if there is no intersection, a green one if there is an intersection.

Please note that while the example uses an entity to generate a box, it is not necessary. The whole point is to perform intersection checks against non physical objects, for example an in-world user interface screen, or testing if a player (or an NPC) is looking at a certain part of a map.

-- Store entity we look at local ent = NULL -- Do this every frame hook.Add( "Think", "Think_IntersectRayWithOBBExample", function() -- Store player object local ply = Entity( 1 ) -- If player looked at some valid entity, swtich our entity to that local trEnt = ply:GetEyeTrace().Entity if ( IsValid( trEnt ) ) then ent = trEnt end -- No entity? do nothing if ( !IsValid( ent ) ) then return end -- Perform a ray intersection against the entity's OBB from the player's eyes local hitPos, hitNormal, frac = util.IntersectRayWithOBB( ply:GetShootPos(), ply:GetAimVector() * 500, ent:GetPos() + ent:OBBCenter(), ent:GetAngles(), ent:OBBMins(), ent:OBBMaxs() ) -- print( "res: ", hitPos, hitNormal, frac ) -- For debugging -- Draw the OBB visualization, requires developer 1 in console. debugoverlay.BoxAngles( ent:OBBCenter() + ent:GetPos(), ent:OBBMins(), ent:OBBMaxs(), ent:GetAngles(), 0.01, hitPos != nil and Color(0,255,0) or Color( 255,0, 0) ) end )