Car wheel animation

Do doubt this question has been asked a million times before…

I’m doing a car animation and I need to have the wheels turn in preportion to the speed that they (or some other child object, since the whole car is parented to a main mesh) move.

Does the answer lie in drivers? If so, how do I use drivers?

This whole subject is confusing. Thanks in advance.

Howdy,

There was a thread on a rolling ball here http://blenderartists.org/forum/showthread.php?t=186654

Since then, I’ve found a way write a script that gets run on a pseudo frame change event http://blenderartists.org/forum/showthread.php?t=203982&p=1752470&highlight=#post1752470

Putting the two together one could write a driver to calculate the rotation using the fcurves to calculate the distance travelled from the frame before. That way you can key in location and calculate the speed each frame by passing the framenumber and the name of the wheel via the driver.

This may be more than you are looking for. :slight_smile:

Enjoy!

The car autodrive system relies on the wheel-rotation script that in 2.4x is fired by the onframechange event, which is no longer available in 2.5x. Which version are we looking at?

I’m using 2.55
I know that you don’t have to use a script - I’m looking for that solution, so don’t tell me about any scripts or anything, I know there is an IPO driver solution, I just don’t know how to do it

This is one of Roubal’s very early non-script versions. (Same guy who later did the Jeep with tracks in the sand)

I hope all the functionality is in Blender 2.5. It should be, as I don’t think he is using anything out of the ordinary.

I actually have that one… my problem is the one part about adding a driver to make the wheels turn in preportion to the speed

in 2.5, You can setup a constraint system that rotates the wheel that is proportional to the movement of the car, like this: http://mikepan.com/files/BMW3v2.blend

Thanks you mpan3!! man its so simple…

fantastic modeling, ,lighting and compositing!

Hi Mike,

Thanks for this. Would it be possible to use your method for both the X and the Y axis (world/global space)? I notice that, at the moment your setup only works for the global X-axis.

I tried adding another axis, but I did not succeed…

Same here… that method only works when traveling in a straight line

If you “drive” your car along a path using a curve modifier or follow path where the travel on the curve is mapped to a particular direction then the method works fine.

Rather than use the straight out constraint i have used a driver, which for all extents and purposes does the same thing … but allows me to fiddle with “overspin” for burnouts or “underspin” for braking.

Cheers for the method Mike.

@batFINGER See that’s what I would like, but I just do not know how to use drivers in 2.5

Here is a sample of using the location to rotation transform using drivers. I stripped this out of another file so some of the objects in there aren’t required. This method has been very useful to me as i had been keying in a velocity.

Merry Xmas.