Animating Wheels

[DangerousCliff]

roller (http://www.habware.at/max6/Roller6.zip) might be helpful.

can find it and other useful plugins at www.maxplugins.de

[Kinneas]

Thanks alot. That plugin helped greatly.:thumbsup:

[Tafh]

You don't need a plugin for this:

-select the object you want to rotate
-hit rotate
-tools -> transform type-in now make sure you type in the "offset:world" how much degrees rotation you want, for instance 3600 if you want it to rotate 10 times :)

[LoneRobot]

-select the object you want to rotate
-hit rotate
-tools -> transform type-in now make sure you type in the "offset:world" how much degrees rotation you want, for instance 3600 if you want it to rotate 10 times :)



er.. no that's not the way to calculate a rotation of a wheel. a wheel will travel at different speeds acording to its radius and the distance it's travelled. So you cant just rotate it 10 times. I'd use cliff's suggestion - it does all that deg to rad math for you. much better. :)

[Headless]

Reactor has a car wheel constraint built in. Check the Max User Reference for more info.

[Maniac618]

aaaaaaaaaaaaaaaaaaaargh, im trying to rotate some car wheels in an animation, im not too bothered about the wheels matching the car speed as i have some camera angles to hide that problem, i cant use extra plugins for this and im having difficulty actually getting it to work.

Im doing the following:

set key
key frame 0

moving to frame 148

rotating the wheels with rotate and set key on
key frame 148

the wheel doesnt rotate when i play it.

help.

[Maniac618]

pleeeeeeeeeeeeeease help.

[desmondying]

strange..

What you're doing seems to be correct.

Have you checked the curve editor? (use out of range types if needed)
or like Kinneas mentioned, to use helpers / dummies to rotate the wheels?

I did wheel rotation with helpers way back in version 5 and all i did was use rotate and set keys, so i'm not entirely sure what went wrong.

[timothyjpalmer]

Really don't see how you can have a problem. How many rotations are you trying to do? Have you tried autokey?

[joconnell]

Okay one thing that maye be causing a problem is if you are using a tcb rotation controller on your object - they use a "shortest way around" rule which pretty much means if you rotate something from 0 degrees to 359 degrees, what the rotation controller will do is find the shortest way to go from one rotation to the next which is to rotate your object -1 degrees over the length of the animation. One way to solve this is to add more keyframes between the first two to lead the rotation controller in the right direction so set one at 0 degrees, 120 degrees, 240 degrees and finally 360 degrees.

The alternative would be to change your rotation controller to euler xyz and then you can use your function curves to control the direction of the wheel - euler xyz controllers have their own problems like gimbal lock and axis flipping but for soemthing simple like a wheel this hopefulyl wont be a problem. Check the max help about assigning animation controllers to point you in the right direction.

[Maniac618]

Thanks for the help guys, but I'm still lost. I tried euler xyz and got even more stumped.

[andrewjohn81]

go to the curve editor

select the second key and note that it says value of rotation at the bottom.

If it indeed did shortest way around (that's my guess too) then you can simply type in the number that it showed you in the viewport.

OR, you can just drag the key up or down, depending on which way it's rotating, and that will rotate the wheel further in either direction.

If you do it in the curve editor I don't see any way that the wheel can go the wrong way.

[Maniac618]

I just tried the curve editor but it only lets me move the whole editable mesh and not the element of the wheels i want to rotate. I think this is the problem...

the wheels are part of the editable mesh which is the whole car. They are individual elements within it however and i can select them seperately from the rest of the car.

However i think it has something to do with that. If i detach them however they would then not be moving with the car.

Grrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr :(

[timothyjpalmer]

bind the wheels to the car or a dummy ;)

[Maniac618]

Hmm the wheels are now rotating, but they are getting smaller as well and earlier than I want them to move anyway....

Could someone briefly list the exact method of timelining rotation i want. All i know is i want the wheels to start rotating at 125 and end at 248.

What would be the exact step by step for this using the keys, I've read stuff but its doing my head in.

[Maniac618]

:( It can't be this hard.

Edit: Done it, but craply.

[eodeo]

I had a similar problem just a week ago. I had a character that needed to push a catapult that had big front and small back wheels. On top of that, all wheels had small spikes all over, to help it grip to the ground. What I ended up doing is rigging the toycar to catapult and linking a box to biped's hands and making the box unyielding.



I had to tweak it a lot, but after about two hours of testing I got a near perfect sim. Then I just hand keyed the bad parts and the result was amazing.(if I can say that about something self made :p)

---
EoDEo

It is pointless to be foolish at this time

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