View Full Version : expressions: how to have tire rotate automatically?

02 February 2003, 05:16 PM
Hey guys. I'm wondering if anyone knows of a tutorial showing how to set up a wheel with expressions to rotate automatically as the object is moved. Basically I want the wheels of a car to spin correctly (automatically) when I move the car itself.


Lightwave 7.5 (mac)

02 February 2003, 06:04 PM

for lw tutorials

02 February 2003, 06:20 PM
I dont think I've seen any plugs/expressions that can rotate a wheel dependant on both x and z position changes

at least not for a PC :)

btw delta,check your mail

02 February 2003, 06:37 PM
If I remember correctly, I think both the Polk Collection from Worley
and Prem's Relativity will handle this kind of thing...

02 February 2003, 06:45 PM
there you go... :)
as soon as you say "there isnt any..." somebody will come in & save the day

it's only a matter of your way of asking

02 February 2003, 07:25 PM
LNT: Hm... i got a messege from proton, how did you know that? i thought you sent me something. heh

Rabid pitbull
02 February 2003, 07:29 PM
Originally posted by UserDelta
LNT: Hm... i got a messege from proton, how did you know that? i thought you sent me something. heh

ok UD keep the info to yourself, and dont start and RUMORS!!

:scream: :D :rolleyes:

02 February 2003, 07:31 PM
hehe sorry, i was confused for a bit. was weird.

02 February 2003, 07:37 PM
just had to do it several days ago and i found a nice tutorial in one of the lw book (i think it was LW applied)..
they use there the cyclist plugin that comes with LW (first time i really understood whats it for)
first you make a 10 frame animation for your wheel of 360 degrees
then you give your wheel the cyclist motion modifier ,uncheck the unnecessary channels (leaving only the channel that rotate your wheel)
cycles frames - from 0 to 10 (thats your animation to be repeated)
cycle controller - here you choose your master mover object
choose path length
controller range - from 0 to your wheel diameter (its the radius*pi)
end behavior - set to repeat
thats it - no commercial plugins or expressions and you are not limited to one axis and can even do with it things like walk cycles
hope this helps

Rumpus King
02 February 2003, 07:53 PM
Worley wrote Wheelie (part of the Polk collection) specifically for this. You're good to go using Cyclist though. I've noticed that some of the Polk plugins have trouble when you wanna load from scene.

02 February 2003, 08:02 PM
Thanks guys. Cyclist worked great. Thanks everyone for your help.

02 February 2003, 08:20 PM
no delta,
I PM'd you thru Incision :)

02 February 2003, 12:29 AM
I also have a free rig on my site showing a simple way to get tires to deform while they rotate.

02 February 2003, 03:55 AM
Here's the expression for rotating a wheel based on another objects x and z position:

360*vmag( Null.pos(Time)- Null.pos(0))/1.0

Null = object you want it to follow
1.0 = radius of wheel

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