Raycast against terrain3D at -x yields no/error results?

[andreasng]

I admit i'm not a coder, in any shape or form, but i have this raycast here(which "works", but not...):

func raycast_to_world(start_position: Vector3) -> Vector3:
	var ray_params = PhysicsRayQueryParameters3D.new()
	ray_params.from = start_position + Vector3(.0, rayHeight, .0)
	ray_params.to = start_position + Vector3(.0, -rayHeight, .0)
	ray_params.hit_back_faces = true #-----------tried this doesnt make a difference
	ray_params.hit_from_inside = true #----------tried this doesnt make a difference
	ray_params.collide_with_areas = false
	ray_params.collide_with_bodies = true
	ray_params.collision_mask = 0b00000000_00000000_00001000_00000000 #12 - my terrain mask id

	var space_state = get_world_3d().direct_space_state
	var result = space_state.intersect_ray(ray_params)
	
	#print(result) #<--------------------this will crash the game if raycasting against negative x

	if result:
		return result.position
	else:
		print("raycast failed!")

And if I raycast at ie. position 4,-2,-8 its fine. also at .2,17,500....
But if i get into the negative x positions it yields nothing.

Does this make sense because the code is rubbish, or is it a temporary bug in the system?

[TokisanGames]

print(result)

This shouldn't crash ever, no matter the value. If so, that's a godot bug and nothing to do with Terrain3D.

Is collision enabled?

Do you have regions defined where you are raycasting?

Did you read this?
https://terrain3d.readthedocs.io/en/stable/docs/collision.html

Vertical raycasting can be entirely replaced with get_height(). Non-vertical can be replaced with get_intersection() though see #511 and #511 (comment)

[andreasng]

yes i am as confused as ever. I run around on the entire terrain just fine. but this is just puzzling.
get height is for terrain? I'll try that (and probably want it instead!)

[andreasng]

oh....
"This function works fine if called only once per frame, such as for a mouse pointer detecting terrain position. More than once per frame will produce conflicts."
i planned on doing this ... alot...

[andreasng]

Query Many Heights is for me then

[TokisanGames]

I run around on the entire terrain just fine.

If you're using this for a player you should use physics move_and_slide, just like in our demo.

If you want to do a vertical raycast, you should use get_height instead.

Raycasts do work fine when properly setup in code, within regions, with collision.

[andreasng]

ALRIGHT!!!!1

after extensive testing i have now found a very very idiotic solution to this. And i will retain that either godot or terrain3d has a flaw in how raycasting collides with it. Let me explain:

This will fail. and crash if you query result.collider.name forexample

func raycast_to_world(start_position: Vector3) -> Vector3:
	print("raycast origin: ", start_position)
	var ray_params = PhysicsRayQueryParameters3D.new()
	ray_params.from = start_position + Vector3(0.0, rayHeight, 0.0)
	ray_params.to = start_position - Vector3(0.0, rayHeight, 0.0)
	ray_params.collide_with_bodies = true
	ray_params.collision_mask = 0b00000000_00000000_00001000_00000000 #12 - terrain
	var result = get_world_3d().direct_space_state.intersect_ray(ray_params)
	print(result)

BUT... i work with unreal daily at work, and i came to think about a thing unreal had where rays that were clean traces (ie not a sphere trace or a box trace, but just a laser pointer trace) would .... "seep".... through ......................"cracks" in ALL collision.

So as a hail mary i modified this little tiny tiny thing:

func raycast_to_world(start_position: Vector3) -> Vector3:
	print("raycast origin: ", start_position)
	var ray_params = PhysicsRayQueryParameters3D.new()
	ray_params.from = start_position + Vector3(0.1, rayHeight, 0.1)
	ray_params.to = start_position - Vector3(0.1, rayHeight, 0.1)
	ray_params.collide_with_bodies = true
	ray_params.collision_mask = 0b00000000_00000000_00001000_00000000 #12 - terrain
	var result = get_world_3d().direct_space_state.intersect_ray(ray_params)
	print(result)

Can you spot the difference?

yes. The ray is not straight, and i might, for good measure, "flicker" it as well.

Toki, i hope you will have a look at this and see if it is a major flaw in godot, or a little easy fix in t3d.

peace! 😆 🚀