All of the credits go to JC#21, which made this tutorial in french at motonline-france.com. All images are available at full size by clicking it
Part I - Pivot positionning- Select your chain object
- Go to "Hierarchy"
- Affect to pivot only
- Move the pivot at (0,0,0)
- Be sure to have the axis in the correct directions
Part II - Gearbox output- Create an object (a sphere is perfect for that)
- Move it to the middle of the gearbox side of the chain using the left view
- The values we'll be using in the gfx.cfg appear at the bottom of 3ds Max
Part III - GFX file- Open your gfx.cfg
- Go to the chain section
chain
{
name = chain
pos
{
x = -63.175
y = 0
z = -10.107
}
engine
{
x = 0.0
y = 0.0
z = 0.00
}
texture = chain
axis = v-
ratio = 0.016666
}
- The values in the "pos" section are the one which need to be changed. (values from 3ds Max)
Note : GP-Bikes and 3ds Max are not using the same axis. Check the previous picture to see how to choose the values.
Here's the corespondences between both :
GPbikes 3ds Max X = -Y Y = X Z = -Z |
Part IV - AdjustmentsWith what we've done here, you should already be able to see a rotating chain ingame. The thing is that it's probably not well positionned. We'll see how to put it in the correct position.
Ingame screenshot :

In 3ds Max :

We can see that we need to rotate a bit the chain.
- Rotate de chain arround its axis on the rear wheel.
- Move the sphere we've created before at the correct position compared to the ingame screenshot.
- Update the values in the gfx.cfg.

Part V - ResultsNow we've got a beauriful ingame chain, which rotate perfectly!
Part VI - Possible bugsIf the chain doesn't rotate in the correct direction, it should come from the unwrapping. Just edit the UVW unwrap, by mirroring it. It should works!