View Full Version : Rigging a Tracked Vehicle
01 January 2006, 06:22 AM
I'm about to embark on rigging a realistic tank. The idea being it can bounce and hopefully i can find a way for the tread to react to the surface it is on.
I was wondering if anyone had any tidbits to get me started. I assume it's going to be like having a car with 16 wheels and no steering. I haven't found any tutorials on tracked vehicles, just some little snippets.
02 February 2006, 08:19 PM
Oh, cool, I'm making one of those track equipped vehicles too.. What I did was to build one link of the track and put the pivot in the center of it. Then I created a track curve from three NURBS circles, one for each of my main wheels (it's a wheel setup similar to a bulldozer). I snap created CV curves between then, trimmed, joined and so on. Then I rebuilt the whole curve with about 64 CVs I think.. The next step is the funniest. I found a great script which automates the boring process of creating your own motion paths with expressions. I once did this by hand on 122 chain links in a motor, and I swear that I will never do that again. :)
lHere is the script. (http://www.highend3d.com/maya/downloads/mel_scripts/animation/3413.html)
The script brings up a small window where you enter the names of the link, track and aim object. The aim object is supposed to sit in the center of the track to align them.
After that you just have to rig so that your wheels turn with the track and on. To make the tracks bounce and deform you just apply your favourite deformer to the track curve, like a lattice with clusters for the wheels or something similar.
02 February 2006, 09:47 PM
Thanks for the tip off about the script. Looks good. Seems to have the same features as Radiant Squares tread script. Your one has more control when creating it.
You got me thinking, I was searching about highend3d before, and didn't find much. I think i mush have been searching for tank, or track, or misspelled tread as thread. Anyway. i found another script. This one looks great.
Does the drive wheels, and even the differential when turning! Thats going to help alot :beer:
Next step is the suspension animation.
02 February 2006, 11:26 AM
Cool. I think Ive acctauly downloaded that script some time ago, but I never used it for some reason. Thanks for the tip though, cool with the diffrentioal turning stuff.
Good luck with your project,
02 February 2006, 09:29 PM
thanks, lets trade pics when we're done.
Are you having problems with your undo after using this script? It seems my undo queue turned itself off once (could have me doing something wrong). Then if you play and stop animation, my undos doesn't do what I'd think, and it just takes away a tread object per undo. Weird.
02 February 2006, 09:55 AM
Yeah, sure trading pics would be very nice. I might as well set up a wip thread, maybe...
Hmm, I have some issues with my undo. Not that it turns itself off, it just seems like the script executes a lot of commands, which are a pain to undo by hand. If I want to test the track or something I execute the script, do the um testing, and then delete the whole track group. That way the expressions are also deleted. Now when I'm working with the internals of the track I just have the curve and one link left, saves some polys for the viewport too..
02 February 2006, 02:46 AM
ya. I've also had problems making the track itself, it'll make some of the tread flipped 180 from the track curve.
As for testing animation, the script seems to come with some test animation section. I guess we're supposed to use that.
01 January 2007, 10:57 AM
Your last comment, how you had problems with the tread flipping 180, Im having that problem now.. where the bottom tread will be at 0 and once it goes round to the top, it flips to 180.
I was wondering what you done to overcome this?
01 January 2007, 08:07 AM
You can also try this script. It will create series of joints on a motion path from a curve object:
To execute, select a curve and run the script. A window and an interactive slider for creating a number of joints will appear. The second option creates a group of motion pathed joints on a curve. There is an option to control the World Up Type of the up vector of the motion paths, which I think is the problem with you flipping track pieces (you have to deterine how your motion path gets it's up vector, usually you indicate a world up object and a world up type). To get the correct world up type, you can display the axis of the joints to see if they still flip. On the motion path joints option, choose acquire retract attribute and cyle attribute, these will appear on your control curve. You'll use the cycle attribute to roll the track.
After creating the joints, you can then point and orient constraint track segments to each joint to get a caterpillar track rig.
01 January 2007, 08:07 AM
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