PDA

View Full Version : making a controllable sphere (or ball) roll over terrain



dsol
04-14-2015, 09:48 AM
Hi, I'm trying to animate a "marble madness" type scene, with a ball character rolling over a simple terrain (keyframed X and Z position). I'm trying to work out if there's a way of making it look like it's rolling correctly. I can make it stick to the surface using the raycasting node, but I've no idea how to make it rotate to reflect the direction and velocity of its movement. I know some people have used expressions to make car tyres roll based on movement, but this seems way more complicated as you need to rotate on all axis.

I'd be eternally grateful if anyone's got any ideas about how to do this - it's driving me nuts!

souzou
04-14-2015, 03:54 PM
I had an idea for this, using bullet dynamics with a constraint. So you have your ball object and ground as rigid bodies, and then constrain the ball to a null which is keyframed with your animation. I hadn't used constraints in 2015 yet so this was *really* quickly hacked together but it works after a fashion. Looks a bit dodgy if you have sudden sideways movements but might work for you.

127864

Quick example:

http://www.souzou.co.uk/video/ball_example.mp4

Danner
04-15-2015, 05:39 AM
http://forums.newtek.com/showthread.php?134505-How-the-heck-do-I-roll-a-marble-around-on-a-floor
Some ideas there might help.

jeric_synergy
04-15-2015, 07:57 AM
Dang it, now I'm craving Marble Madness.