Pulling Hair Out

Development Programming & Scripting Blueprint
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Hello all, long time lurker, just created my account recently and i guess this would be my first post.

So i am working on a car game, and i have been running into troubles, and i think it might be due to my car blueprint or something

EDIT4: I have fixed it. my wheels and tires needed a skeleton, made the skelmeshs with just a single root bone. and boom everything works, fully socket-able tires and rims! yay.

EDIT3: IT HAS to be something to do with the WheelBack/WheelFront blueprints…
if i make the radius 30 the car flops on the ground, i can “drive” in the fact that the wheels and rims rotate, i can turn, it all looks GREAT. but the car don’t actually move, it just sits on the body (i have gone as far as removing collision from the rims and tires for testing).

if i set the radius to 40. the vehicle just fly’s off into space…

EDIT2: I have narrowed it down to rotating my object in maya to +X before export, then after import, i start the car just flops down.
this is due to my “wheel” blueprints, if i set the radius 1 below the size of my wheels nothing happens, if i set it to the same size or 1 unit bigger,
the car instantly flys off into space after spawning… ffs, im so close, yet so far away… anyone… please…

EDIT: ive managed to make it able to spawn me again. i had to set Z up in Maya… and Z-Up in FBX.

NOW im able to attach the wheels and they seem to work, however when i go to start driving… i fly! (you can see the wheels rotating on +X, car is facing +Y…)

and if i rotate my car on import, the collision makes me fly away instantly. so its attempt to drive the wrong way or bounce off the map… :frowning:

Here is what I’m trying to achieve, I’m trying to make it so i have a car mesh, with bones for hubs, then i have a mesh for wheels, and a mesh for tires,

I’m placing the rims and tires onto the main car mesh sockets (I want to be able to interchange rims and tire tread at will)

so in the world the car looks normal, i have the mesh, wheels, and rims, all is good.

I hit play, and my vehicle is… gone… like physx to the max out of the park flipping at mach 20+.

so i figure perhaps its my collisions / model / physics setup.

so i open Maya, i make a box with the core components, root, and four wheel locations. (root is 0,0,0).

i open the physics mesh editor delete all collisions, make just one box around the body simple box.

So here i am, i can’t even get the car to spawn into the world via blueprint, and i haven’t even started to tackle making the vehicle drive-able with wheels / tires socketed on 0_0

… I’m going to make more coffee. someone. please help.

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First thing that comes to mind, are the tires/wheels also imported as Z-Up? Both need to be X-Axis positive (front of car pointing positive X) and Z-Up.

Although your vehicle’s root is at 0,0,0, the crazy physics seems to occur when the root bone (and wheel bones) have a rotation value that is not 0.0,0.0,0.0.

In 3dsMax the bone rotations are by default -90.0 on the Z axis, which is a problem when imported to UE4. For Maya however you will need to rotate each bone so that Z-up = 0,0,0 which should be -90x, 0y, 0z in Maya.

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Thank you for the reply.

**EDIT: IT HAS to be something to do with the WheelBack/WheelFront blueprints…
if i make the radius 30 the car flops on the ground, i can “drive” in the fact that the wheels and rims rotate, i can turn, it all looks GREAT. but the car don’t actually move, it just sits on the body (i have gone as far as removing collision from the rims and tires for testing).

if i set the radius to 40. the vehicle just fly’s off into space…**

So the rims and tires have no bones, just mesh attached to the socket of the wheel are they required to have a bone? they seem to attach and work normal.

The first few times i tried importing the car with Maya +y then, then importing with -90x the physics was horrrrible, then when i tried modeling up the basic car, flipping it so it was +X, then zeroing everything out, it imported and the physics was perfect!

however when the “frontwheel” or “backwheel” blueprints have a radius that is large enough to “lift” the car off the ground per say, that’s when the physics go just bonkers.

Should i be modeling it in Maya with +Y, Z up, then importing with -90 on the x axis?

I seem to have the best results when i face the car +X then zero everything out.