Godot 4: Character to Rigid Body Interaction

Key Takeaways

welcome to another Godot recipes video this time around we're going to talk about how to use a character body to interact with a rigid body one of the most common physics related questions that comes up in Godot is when you have a character body like my little green Cube here and these red squares are rigid bodies and if all you do is add your character body and your rigid bodies and you're trying to push them you'll see nothing happens you can't push them and it doesn't matter what you set their Mass to they won't move this is the default Behavior the rigid bodies which are controlled by the physics engine are not detecting any collision with the character body which is being moved in code to solve this we have two options in the project settings I've created three physics layers one for the world one for the player and one for items such as the Box and then I've placed each object in those layers so the player node is in Layer Two and the box is in layer three and that's the default Behavior if we ran it right now nothing will have changed but let's go into the player mask and remove three so now when the player moves it will not detect collisions with the rigid bodies so it's just going to plow right through them but the rigid body is going to still try and separate because the rigid body can see layer 2 which the player is on so it's going to want to keep its Collision box separated so let's try that and see what that looks like so now you can see I'm pushing them however there are some problems if I keep pushing against it I it will clip through the wall and you are not able to jump on top of them because you'll push them right through the ground Collision those of you who are familiar with good O3 will recognize this as the default Behavior which was called infinite inertia in that version of movement slide and so for some games this will be this will be just fine you can shove the boxes they fall over and you're not concerned with wall glitches and such but if you want something a little more robust where things do not glitch out when you push into the box then we need to try option number two okay for this option we're going to put the mask back so we're back to the way we started the character body won't push the rigid body and this time we're going to add some code into our player so when the character body hits a rigid body it's going to apply an Impulse or a push to the rigid body so in our player code we're going to add a variable here to control how strong that force is and then in our physics process after a move and slide we're going to get the slide Collision and if the thing we collided with was a rigid body then we're going to apply an Impulse in the opposite direction from the Collision normal which will mean into the rigid body using that push Force so now when we run we'll see we can push but now if I push against the wall I can't push it through the wall and if I jump on top of it I also can't glitch it through the ground but I can push them and they'll slide up hills and so on now how strongly you want to set that push force is going to depend on a few factors how fast your character moves how massive the boxes are as you can see here the boxes I've given them a mass of one if the boxes have a really high mass you're going to need a stronger push Force and so it's something you're going to have to adjust based on your particular game this will work just as well in 3D as it does in the 2D example here and some other things you might want to try for your game if you're experimenting with this is to perhaps move use the velocity of your player as a factor in the push Force you can scale it up or down based on how fast your character is moving things like that you can find this in many other good old recipes tutorials examples and tips at good or recipes.com don't forget to like And subscribe on YouTube to get the latest video tutorials and if you'd like to help support these efforts please consider clicking the patreon link thanks