How to do tire collision for driving in UE4.18?

Me and an ‘associate’ are working together to start the beginnings of a vehicle game. However we are running into a few issues with the modeling side, and more specifically the collisions for the vehicle.

At the moment our main issue is the fact that the vehicle never moves. Either the tires are slightly off the ground, or colliding through the floor about halfway, no matter how I set the collisions in PhAT. The animation for the wheels rolling works correctly, as well as the steering.

Our main sources of reference have been:

Vehicle Art: https://docs.unrealengine.com/latest...ntentCreation/
Vehicle User Guide: https://docs.unrealengine.com/latest...icleUserGuide/

We have followed the contents very strictly so are unsure why we are still having issues. Looked around on the forums too but all the solutions we have tried have been to no avail.

I have attached a screenshot of our model and the PhAT setup. The PhAT setup is the thing that I am most unsure of, so is perhaps where the issue is lying.

Thank you for reading and hope someone can give some feedback.

Hey,

The first thing to note is that your vehicle’s box collision seems too big! Make sure it is the size of your vehicle’s body only (excluding the wheels) to prevent it from touching the ground. Take a look at VehicleGame project provided by Epic for an idea on how to set up collision.

Usually, most issues with a vehicle such as sinking wheels or vehicle not moving even though tires rotate are caused by the improper rigging of the vehicle. I’m not familiar with Blender’s interface but it looks like your wheels’ pivots are facing opposing direction! Make sure that the root bone’s pivot and all other bones’ pivots are having their “x” axis facing toward the front of the vehicle as in the picture below:

Image source: Rigging a Car for Unreal - World Creation - Unreal Engine Forums

Lastly, make sure that in your vehicle’s blueprint, under the vehicle setup category > wheels setup, you have added wheels blueprints with their corresponding bone name.

Hope this helps.

Thank you for the reply.

We have updated the PhAT collision model so it now looks like this:

While not perfect still, it is a much better approximation of the vehicle. Been careful to make sure that all of the bottom of the vehicle is accounted for within the box.

We have also updated the model itself ensuring that the root bone is at 0,0,0 and that all pivots are facing towards x+:

Unfortunately the issue of the tires colliding through the floor still persists. Wheel setup within the vehicle blueprint is already in place, with the bone names matching the skeleton. Front wheel bones with the front tires, and rear wheel bones with the rear tires.

hmm… that’s strange. I just checked the vehicles in my own project and to my surprise, and in contrary of what the official Epic tutorial says in here (step 5), my physics types are all set to default! Try changing it to default for each one of your collision components. Also, make sure that all Angular limits are set to “free” and the Angular Motor to SLERP for each one of your bones.

That’s all I can think of. Hope this resolves your issue.

P.S. Let me know what the issue was whenever you manage to fix it. I would love to know all these common problems with vehicle setup in UE4. Thanks :slight_smile: