Enable physics only on a part of a Skeletal Mesh

Development World Creation
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1

Hello !

I was wondering if it’s possible to enable physics only on a part of a Skeletal mesh. I do think it’s possible but I’m not sure how. My goal is to have a car that keep his wheels to the ground using raytracing (I don’t want the car to jump, etc), and animate the rest of the vehicule localy with physics (since the “logical actor” is replicated correctly, I can simulate physics localy without trouble, this is an RTS, so that should do the trick, that will save a lot of bandwidth).

127276-carturn.jpg
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This image from AoA represents exactly what I’m looking for. Even under a huge speed + rotation, the car keeps its wheels on the ground, but the rest of the car is simulated for more realism (even tho here it’s unrealistic because too extreme). This game doesn’t use UE4, but I guess the process is the same. They probably have one skeletal mesh and the wheels are part of it, but do not respond to physics.

Thanks !

2

You can use the node “Set All Bodies Below Simulate Physics” and set the bone name to start at, from that point to the end of the chain will be simulating physics. In this example using the ThirdPersonCharacter the entire right leg is simulating physics while the rest of the body is not:

127496-setbelowsimphysics.png

3

Hello ! Thanks for the answer. I saw that node already but I’m not sure how to use it in the case of car, because the situation is reversed. With this node, I would have my wheels simulating and not the middle, and I want the exact opposite, I want the wheels not to simulate and the middle to use physics.

4

Hmm…the only thing I can think of then is if you edit the skeleton hierarchy to better utilize that node, so that the wheels are higher in the chain and the body lower, but that may be more of a pain if you have animations etc already.