Hi everybody,

I built a Toyota FJ-40 in 3DS max 2009 (a 4 month modeling and texturing) and I imported it in Poser6 BUT the front wheels don't want to turn in the right way :(

As long as you rotate them on X or Y, no problem but if you want to turn both (for an animation) it's impossible ! It's giving me nightmares :((

I am unable to understand if it comes from my importation, the axis in Poser 6 or an option I forgot to turn on somewhere.

Any help welcome ;-)

Sam

Are the wheels basically teh same part in the model, or are they seperated?   If they are in the same part, then they can only have on origin, so rotate will rotate the wheels around that point.

If the Wheels are seperate then their origins may not be centered correctly, causing them to rotate oddly.

John

You're running into Gimbal Lock, a constant problem in 3d.  You can't rotate an
item on all three axes freely.

The  best solution for a car is to set up a distinct body part to carry each wheel. 
(Real cars actually have this part, called a "spindle", so it's not just a 3d trick!)
The spindle takes care of the Y-rot, and the wheel (parented to the spindle)
rotates on X. 

Look at the underside of my Renault for a simple example of suspension, spindle
and wheel.

http://www.sharecg.com/v/17504/Poser/Renault-R8

A good explanation of Gimbal Lock:
http://guerrillacg.org/home/3d-rigging/euler-rotations-explained

Attached Link: ERC Download Page

If their centers are okay, the way to make them turn together is to use ERC code.  Some code needs to be manually inserted in the Body, and the Y rotation channels of each wheel.  The code in the Body will give you a new dial, and the code in the wheels will make them react to the new dial.

This is really quite simple.  See the link for tutorials on the subject.  If that's not the problem, please explain exactly what is happening..

John

Quote - ...the front wheels don't want to turn in the right way :(

Whatever the problem is, it can be fixed. Unfortunately "don't want to turn in the right way" does not give enough information for me to understand exactly what the problem is, and "X or Y, no problem" does not help, when you don't say what x and y currently do, ie we don't know the orientation of x and y relative to the long axis of the car. Are you referring to the wheels spinning as when the car is moving, or to them turning from side to side as when the car is turning a corner? Or both? What exactly happens when you try to turn the wheels in the desired way, and how does this differ from what you want to happen? What affect does each rotation currently have on a wheel? Is this a pp2, or a cr2? Is each wheel a separate geometry group?

You can change the position of the axis of rotation, and the orientation of the axis in the Joint Editor. You should be able to overcome any gimbal lock problems by chaining the order of the rotation channels in the channel stack (as a car wheel only needs to rotate round two axes). But without more info on exactly what the problem is, it is hard to give a more detailed answer.

Hello Guys,

THanks for your explanations :) I can't answer properly right now since I am working but in a couple of hours or so I will let you know... sounds like I will work a lot :)

Working on it, will keep in touch soon :)

Well, well, well...

Spent 4 hours on it, tried, failed and tried again... went to bed at 2 in the morning...

AND IT 'S NOT WORKINGGGGGGGGGGGGG !

So, I will be more precise about my problem, sending some pictures this evening (I live in Marseille so it will be evening here)

Your posts gave me some clue, indeed :) Sounds like a gimbal problem, but where can I solve it ? 3DS max or Poser or .pp2 ? Or somewhere else...

All the best from Provence

Sam

You may need to reset the axis for the wheel , and the front whels should be seperate, the rear wheels can be a single unit if you prefer.

Post a picture when you can .

The wheel is modeled as a separate part and imported in poser then I parented it to the body of my 4wd.

In 3ds max, I set the axis as a local one the I had to change it again in poser using the display origin as shown in the 4th pic.

And that's all I can do... Should I change something before, later or in .pp2 ? It can be that difficult :(

BTW what is the joint editor ? Can it help me ^--^ ?

Thank you,

SAM

I think you'll need to change the order of the axes using Poser's Joint Editor.
Someone already mentioned checking that the axis are properly aligned, which again you can do and correct with the Joint Editor.

You'll find the Joint Editor on the Windows menu in Poser.

YEEPPEEEE YHEAAAAAAAAAAAAAAAA

Thank you so much to all of you !

IT'S WORKING !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Using the joint editor I changed the order of the axis to avoid the gimbal problem. Instead of YZX, I tried XYZ and it's working !

Thank you again ;)

Sam

Glad to see you got it working.

remember in max the z axis I think is UP and in Poser thats the Y axis. There is a setting in the exporter to obj that will fix that. 

Good to hear you have it working. Joint editor, centers and axis alignment is important for making mechanical stuff.

From what I can see of it it looks like a nice model, well done.

And thank you again :-)

Here is my 4wd, it's a FJ-40 from TOYOTA

Sam