Unity 5 - Wheelcollider wrong rotation

Hello Unity.

Some time ago I posted a question about the unity 5 wheel colliders sinking into the ground.
I concluded that it must've been the rotation of the wheel collider that just looked outright wrong. I got my theory confirmed when I saw this posted on twitter: https://pbs.twimg.com/media/CAx-5OkWwAA0I18.jpg:large

You can see how my colliders looked when I asked the question back then:
http://forum.unity3d.com/threads/unity-5-wheelcolliders-sinks-into-the-ground.339463/#post-2204318

Here's mine now, after some deleting, editing and adding again:


What is seriously going on? Now it's rotated on a really special angle. I swear, I did not do anything that could've made it rotate on that angle.

The more I mess about with these colliders, the more problems I get.

-Thanks.

 

Hi Mads232, For starting I use this Unity free tools included with Unity 5

https://www.assetstore.unity3d.com/en/#!/content/21064
I use the car as starting game object.
It is not the answer you are looking for but can takes out of the problem fast.

 

I saw a comment that a wheel colliders up is based on rigidbody up.

Them some odd angles you got though. Are they the scene view? (As in not playing)

 

WheelColliders always point in the "forward" and "down" direction as the rigidbody they're attached to. The steerAngle value is relative to the rigidbody's forward direction.

 

Thank you for your suggestions and answers.

JamesLeeNZ yes this is in scene view. I do have some weird rotations from blender but as it is of now, the parent object's rotation is 0,0,0.

 

Wait, maybe there's still some rotation issues that may make Unity think that the rigidbody's up is not my forklift's up? I'll check that out later

 

Also, can center of mass do such a thing?

 

Are all your rotations 0,0,0 when not in play? You mention your parent, what about the rest? Ideally you will have 0 rotations for everything, including children. Ensuring that will make your life hella easier. Also make sure your pivots are centered, mainly for the wheels.

I dont believe COM will cause your particular issue.

 

Thank you for your reply. Not all things are 0,0,0. For example the forks are rotated 270. It's been a pain in the *** to get it as it is now. The wheelcolliders are attached to a new gameObject which is placed at the wheel's center

 

its more of a pain in the ass to work with non uniform angles imo. I know its easy to reset the pivots in 3dsmax. I assume it aint too difficult in blender. I would recommend the first thing you do is sort that out.

 

You're god damn right. The thing is, Blender's Y and Z axises are switched. I'll try but it might take a while before I'm able to, so I'm still open for suggestions.

 

Its the same in 3ds max. If you reset the pivot, the default imported fxb will have a rotation of 90,0,0. The thing is, you can usually select all objects, reset, rotate, done. Its not hard once you figure it out.

Why might it take a while before youre able to? youll probably save yourself a massive headache if you can.

Incidentally, you can actually edit fxb files in Visual studio (surprisingly). Might have to be 2013 for it to work. I havnt tried resetting pivots using it, but I think you probably can (tbh I was just surprised when it opened)

 

I know what I have to do, no worries. It's just that I'm busy this week so it might take a while before I'm able to.

 

heh all good. I end up resetting pivots a lot in models, so at some point teach yourself how to do it quickly, because its something you're probably gonna end up doing a lot

 

You might try this this Blender To Unity importer.

I've been told that a recent version of Blender has a new experimental option at the FBX exporter that resets some transforms before exporting. I haven't tried, so I can't tell for sure if/how that would work.

 

Thank you for your reply! So does your script also have the ability to fix the rotation with .blend files? I really wanna be able to use the blend files, which I just find very useful.

I think my solution will be to rotate the entire thing 90 degrees.

 

My script fixes the rotations so when you set 0 degrees in Blender, it results in 0 degrees in Unity. Other angles are translated properly so the model in Unity looks exactly as it was designed in Blender.

 

Yes I am aware of that, but does this is only work when I export it as fbx or can I use the .blend file? I don't export to fbx

 

So I tried turning the forklift -90 degrees in blender, which it did not like:



Although by dragging in just the prefab I got the result I wanted. I'm going to try and copy all of the scripts, colliders and everything over to the new one I just created. Then I'll see what the result will be.

 

Now, this looks promising! The wheel colliders looks like they should now.

 

But, now my child object's position (wheel mesh, steering wheel etc) is set to 0,0,0! What the heck is going on here?!

I need those to position the wheel collider!

 

You should be able to change the pivot without changing the rotation of your meshes.

Make sure you delete prebab and re-create after re-importing updated model

 

Well now when I import it, it's automatically rotated -90, but when I remove that, it's as it should be. (0,0,0 rotation) Why does it rotate to -90 itself?

And the position is still 0,0,0

 

So the wheel colliders looks like they should in the scene view, although it just jumps all over the place and through the floor in play mode. I of course expect this to be the settings, so I'm going to figure that out. Got anything on the child position thing?

 

This is what the wheels does when in play mode:

 

Update: I commented out my "visualize wheelmesh" code, and now it looks fine.

 

I still need to fix the position thing though. It messes up the whole thing. Please. Anyone?

 

did you delete it from scene and re-add?

 

Yes

 

are you using GetWorldPose to move your wheel meshes?

 

Yes

 

I think it's the position thing that is messing it up. I've never had this position thing happen

 

where are the colliders? Are the wheels positions matching the colliders position?

 

The above (post #25) only happens when I add the "visualize mesh" thing. (GetWorldPose)


The colliders are just where they should be

 

hmmm.. that' quite strange. tbh, there's not much more I can suggest.

if you want, send me the forklift model and ill import it tonight and fix it up as required.

 

I could, although I would really want to see what you're going to try. For my own learning purposes. I can send the file, but I would appreciate if you told me how you fixed it afterwards Do you have skype or something? PM me with a username.

 

np, pm sent.

 

if you want any handle on wheel collider then attatch rigidbody to that gameobject on which you are applying wheelCollider

 

That is the reason i dont use 3d max or blender, i use Cinema 4D Rxx is better, i set axis to 0,0,0 and stay that way in Unity.

 

Maybe for others that worked but for me it didin't. What did work tho is going to export and than to transform and switching between the forward rotations. For me Y Forward worked!!!

I know that I have been looking for almost 2 days for the solution so I hope this helped you and please share this sothat others don't have to search so long!!! Cheers!

 

An even easier solution is this Blender To Unity FBX exporter:
https://github.com/EdyJ/blender-to-unity-fbx-exporter

 

For anyone with the same issue, this video solved it for me:

Basically: The Local axis in Blender should match Unity axis (i.e. blue facing forward and green facing up). So you have to open edit mode in blender, rotate the object, go back to object mode, then export.