[Robert Cronk]

By the way, I tried just attaching each ball to two very rigid and damped springs which acted as strings and just applied gravity and poof – it worked perfectly! I can even drag the frame that the strings/springs are attached to and the balls move as they would in reality. The springs are invisible though, so I did have to use xpresso to set the two endpoints of a spline (used in a sweep nurbs with a tiny circle to make it look like a thin string) to the ball and to the connection point on the frame so that there would be a visible string, but that’s all eye candy.

So, I got the physics to work and it’s just gravity and two springs per ball (and collisions set to be pretty accurate) and nothing else required! And this is in C4D 9.1! It’s very realistic looking too! Once I get it all pretty, perhaps I’ll upload the scene here, if possible. How do I upload a scene file?

[Robert Cronk]

There’s a sample scene that comes with the dynamics module that is a newton’s cradle that I believe just uses gravity, constraints, and collisions to make it. It’s not perfect though. If you move the frame, for example, it breaks the model. I’d like to see a “real” version of newton’s cradle that would allow me to move the frame and the balls and strings would swing appropriately. Anyone have skills attaching a string to a frame of some sort and then a ball to the other end (or two strings, like the cradle) and then make it so you can move the frame and the ball and string will move like they would in reality? I have tried to use xpresso and combine it with dynamics, but I just can’t figure it all out yet. I wanted to attach the strings to the frame and the ball using xpresso and then forcing the strings to stay a certain length (?) and then apply gravity and collisions or something. I also thought of using super rigid springs to keep the ball connected to the frame through those springs and then the strings would just be connected through xpresso but don’t really have any dynamics applied. That might be real enough, but to make it completely real, the strings should act like string. I think the real problem I’m having is just figuring out how to attach things together in combination with dynamics. If I could do that correctly, I think it should just be as simple as gravity and collisions with nothing special – just like reality. 🙂 Any ideas?