# 3D Raycasts don't always detect Collisions at high distances

`4.3 `

### Question

Hi :),
I’m making a turn-based strategy game and using the following code to update the variable ‘map_hit’ (the position on the map that the mouse is pointing at), using raycasts:

``````var origin = \$Camera3D.project_ray_origin(mouse_pos)
var target = origin + \$Camera3D.project_ray_normal(mouse_pos) * 1000
var space_state = get_world_3d().direct_space_state
var query = PhysicsRayQueryParameters3D.create(origin, target, 2)

var raycast = space_state.intersect_ray(query)
if raycast.size() > 0:
var hit_raw = raycast.position
var hit = Vector3(round(hit_raw.x), hit_raw.y, round(hit_raw.z))
map_hit = Vector3i(hit)
var map_array = Map.all_spaces[Vector2(round(hit_raw.x), round(hit_raw.z))]
var min_distance = 1000
for layer in range(map_array.size()):
if abs(map_array[layer] - hit.y) >= min_distance:
continue
map_hit.y = layer
min_distance = abs(map_array[layer] - hit.y)
else:
print("no collision")
#set map_hit to an arbitrary value where y is below 0
map_hit = Vector3i(0, -1, 0)

``````

But when the camera gets far away from the map, the raycast becomes really inconsistent and doesn’t always detect collisions.
(I would upload a video to make it clearer, but it says new users can’t upload attachments…)
All maps are assigned a HeightMapShape3D when loaded and I’ve already checked that it’s set up correctly (including the collision layers).

Does anyone know what could be the problem?

How far away are we talking about? For huge worlds, you may need to look into large world coordinates. Alternatively, try performing several consecutive raycasts over a smaller distance each (e.g. limit each raycast’s length to 100 units).

Originally, the inconsistencies started at a distance of around 30 to 40 units, but casting multiple rays like you suggested (with a length of 20) seems to have fixed it. Thanks!