How do I make it so that if I spin the dial for the x position, for example, the ball automatically rotates about the y axis and rotates by the correct amount (rotation = distance_travelled/Radius)?  Does this involve writing a script or something?   It would certainly help me animate things easier.

You need to describe what you're talking about with a little more detail. It's easy to just spin a ball with the Y Rotate dial. If you want the ball to "Orbit" something, You'll need to move the ball's "Point of Origin" out away from the body of the sphere using the joint editor and again, spin the Y rotate dial.

You need simple version of ERC (Enhanced Remote Control). Just wait for someone who knows for sure how to make it - I could do some mistakes while explaining since I haven't done this for a long time.

=================

        rotateX xRotate
            {
            name xrot
            initValue 0
            hidden 0
            forceLimits 0
            min -100000
            max 100000
            trackingScale 1
            keys
                {
                static  0
                k  0  0
                }
            interpStyleLocked 0
            }

====================

You'd add the ERC so the paragraph now looks like this:

======================

        rotateX xRotate
            {
            name xrot
            initValue 0
            hidden 0
            forceLimits 0
            min -100000
            max 100000
            trackingScale 1
            keys
                {
                static  0
                k  0  0
                }

            interpStyleLocked 0
            valueOpDeltaAdd
                NO_FIG
                Ball
                xRot
            deltaAddDelta 1.000000
            }

=====================

The NO_FIG is important; the next line (ball) doesn't really matter but has to be there. And the attached file is a script that will give you the correct number to use in deltaAddDelta instead of the 1.000000 in the above text. 

Select the prop, run the script.  It will calculate the prop's diameter and tell you the number for deltaAddDelta.  (I use this all the time when making car models, for the "drive forward" dial.)  The script also works for a body part, as in a wheel.

Download the attached Diameterfinder.py.txt and take off the .txt extension before using.

Thanks ockham!  I'll give it a try.

Almost what ockham said. It's a bit ambiguous what you mean by "x position", but I take this to mean xTranslation.

You put the code in the channel that is to be controlled, and the code "points" to the channel that is to do the controlling. Let's take the Poser ball prop as an example. To have yrot react to xtran, you would use this code in the yrot channel:

           rotateY <span style="color:#ff0000;">yrot
</span>                 {
                        name GetStringRes(1028,10)
                        initValue 0
                        hidden 0
                        forceLimits 0
                        min -100000
                        max 100000
                        trackingScale 1
                        keys
                                {
                                static  0
                                k  0  0
                                }
<span style="color:#00ff00;">                  interpStyleLocked 0
                        valueOpDeltaAdd
                                _NO_FIG_
                                ball_1
                                <span style="color:#ff0000;">xtran
</span>                         deltaAddDelta 360.000000
</span>                 } 

This stuff is called ERC, and the code block which does it is called "slaving code". The deltaAddDelta line determines the strength of the slaving. In the above example "deltaAddDelta 360.000000" means that the prop will do one full rotation for every poser unit travelled. To increase the rate of spin, increase the deltaAddDelta value.

The new !"£$%^& Reply box puts double line spacing in my code. It should be single spaced. :cursing:

Quote - ...and rotates by the correct amount (rotation = distance_travelled/Radius)?

I don't know the formula to work this out, but I would like to. I think it would involve Pi. I hope it involves apple Pi, because that is my favourite kind, I never was much good at math, but I'm good at eating.  :blink:

I think that you can create figure (ball) with one bone. Then load any prop and "point at". Then you can treat prop as a pivot.

For a Poser ball prop, scaled at 100% the correct deltaAddDelta ratio seems to be:

deltaAddDelta 1130.973354

At this value the ball seems to stay in contact with the ground without skidding.

like the above? at x=0, zrot=0 . at x=pi*d, zrot=-360.

Quote - > Quote - ...and rotates by the correct amount (rotation = distance_travelled/Radius)?

I don't know the formula to work this out, but I would like to. I think it would involve Pi. I hope it involves apple Pi, because that is my favourite kind, I never was much good at math, but I'm good at eating.  :blink:

Lol.  Let's say if the ball rotates 360 degrees, then the distance travelled is the circumference of the ball. 

circumference = 2piRadius

The 2pi is the rotation in radians.  So 2pi radians=360 degrees.

So solving for the rotation, you get 2*pi = circumference / Radius

Quote -  like the above? at x=0, zrot=0 . at x=pi*d, zrot=-360.

Yes, exactly.  Here is a simple wheel and axle figure I made to try out the codes with.  It worked! . . .  Well, sort of.   It only works correctly when moving toward the positive x and y directions.   Once you unzip to your Runtime directory, the figure can be found in the Acrionx->WheelAxle folder.

I have this in the .cr2 file for the wheel's rotation: rotateZ zrot { name zrot initValue 0 hidden 0 forceLimits 0 min -360000 max 360000 trackingScale 1 keys { static 0 k 0 0 } interpStyleLocked 0 valueOpDeltaAdd Figure 1 Axle:1 xtran deltaAddDelta -360.000000 } rotateZ zrot { name zrot initValue 0 hidden 0 forceLimits 0 min -360000 max 360000 trackingScale 1 keys { static 0 k 0 0 } interpStyleLocked 0 valueOpDeltaAdd Figure 1 Axle:1 ztran deltaAddDelta 360.000000 }

the text as abv.