Collision Confusion - Unexpected results

[zazoopdi]

Godot Version

v4.1.3.stable.official [f06b6836a]

Question

Hi, and thanks for taking the time to look at my question

After setting up a CharacterBody3D and restricting movement to a 2D grid, I’m trying to create walls for my level. After trying to use GridMap and getting intermittent success, I tried to simplify things down to simple meshes with collision shapes.

However, I’m still getting intermittent and unexpected results - I believe the root of the issue is my misunderstanding/misapplication of move_and_collide()

My desired outcome is something like;

if move_to(new_position) would cause_collision:
      don't_move
else
     move_to(new_pos)

The actual code I’m using is:

func move(new_pos, old_pos): #eased movement
	var collision = move_and_collide(new_pos)
	if collision:
		position = old_pos
		print("Can't go that way")
	else:
		var tween = create_tween()
		tween.tween_property($".", "position", new_pos, move_speed)

The below image are the results I’m getting, with Red = Undesired and Green = Desired - from left to right:

• Door_Closed (with CollisionShape3D) - allows passage
• Open space - allows passage
• Door_Open (no CollisionShape) bars passage
• Wall (with CollisionShape3D - bars passage
• Trying to move in front of last wall - bars passage
• Last wall (identical to other wall, rotated.y 90̊°) bars passage from front, but not from back

All meshes are instanced, and the Door_Closed has the same Shape+Collision nodes copied from the Wall, but give different results!

I’ve also tried deleting the floor, thinking it might be interfering, and changing the sizes of both the Character Collision box and the Walls to no effect

Any guidance or tips greatly appreciated - I’m sure there’s much easier ways to try and achieve my desired outcome, but as a noob I’m struggling.

Cheers!

[J.L]

move_and_collide takes the displacement as an argument, not the destination position. So for your case, the displacement would be new_pos - old_pos.

If it’s touching the floor, then the floor would interfere. You could avoid this by making it so the floor and player can’t collide (different collision layers). Raycasting is another detection option.

[zazoopdi]

Thank you so much <3

I knew I was fundamentally misunderstanding something - this works perfectly as expected now.