Here is a gmax tutorial I wrote back in 2002 that may be of help.
The "c_wheel" animation is used to provide more realism in your steering. It gives greater steering angles (is not dependant on the rudder deflection angle), and only turns when the aircraft is moving. Use of the c_wheel tag is required for castoring.
Once you have a tail or nose gear created and ready for steering animation (suspension animation should be done first), there are just a few basic steps to follow to make it work in flight sim.
Generally, the overview of the procedure (in gmax) is this:
1. Animate the nose gear in GMAX
2. Export to FS
3. Change the aircraft.cfg nose gear contact point.0 parameter 7 to enter steering angle. (This is the angle of deflection in one direction, or set a castoring gear.)
4. Test in FS
ANIMATE IN GMAX
1. Create any low poly basic stucture for the c_wheel tag at the top of your steerable parts hierarchy. All you need here really is the pivot. A small cube or triangle is fine. You may hide it inside the tail/nose gear if you wish. This object becomes the parent of the steerable parts.
2. Now, link the uppermost steerable object to the c_wheel object. All lower parts can be linked to it as well or you can group or link to the uppermost object.
Example hierarchy:
c_wheel (parent of steerable objects-can be below any non-steerable objects as well)
..c_gear_top (extension/retraction animation is on this part)
..c_gear_bottom (suspension animation is on this part)
....c_gear_axle
......c_tire_still
......c_tire_blurred
3. Set the Pivot on c_wheel using LOCAL Coordinate (See attached picture for details.) It's a good idea right here to go to Hierarchy mode and ensure that your nose gear is aligned with the World and grid before proceeding. Once that is correct, align the pivot with the object.
4. Now for the animation. The most important thing to remember here is that once you see animation working in GMAX, it will work in Flight Sim, assuming you have changed the contact point to add steering angle. ;-)
Select the c_wheel object and click on the Motion icon (animation mode)
a. Move the timeframe slider at bottom to the right and create a Rotation key at 100, 150 and 200.
b. Return the slider to 100 and click the Animate button.
c. Move the slider to key position 150, then rotate the Pivot in LOCAL Coordinate mode to RIGHT to 180 degrees.
d. Now, move the slider to keyframe 200, then rotate the Pivot further right to 360/0 degrees
e. Click the Animate button to end the process.
f. Pull the slider back to 100 to see the animation in action
5. Save your work; select all your objects, export to FS and test it.
NOTE that the process may be a bit different in FSDS.
CONTACT POINTS
In the aircraft.cfg Contact Point section, change the 7th parameter of the tail/nose gear (typically) point.0=1
The Steering Angle is the extent of the deflection in one direction. That is if you use 60 degrees, you will have a total of 120 degree movement from totally right turn to totally left turn. The more angle you use, the sharper the turns, however, the greater numbers will also make your steering more sensitive or feel like oversteer of your movements. 60 degrees seems about as high as I can tolerate in that regard. Use 180 degrees for castoring.
Example contact point here for the attached gmax file of my nosegear:
point.0=1, 21.6, 0.0, -5.4, 3200, 0, 1.4, 180, 0.7, 1.8 0.70, 3, 3, 0, 160, 230
TEST
1. To test, export to FS.
2. Associate it with some model file, change the contact point parameters as necessary and watch it in action.
Hope this little tutorial helps you in some way.
(Note that you can use more keys or less in the animation sequence. This one is simply what I chose.)
Kind Regards
Milton Shupe
