-
If anyone can help me animate this, I’ll love you forever
Like the title says, I want to animate this, with full dynamics and collision…the works. This took me the better part of a few hours to figure everything out. The frame is made from a spline, the points of which I had to place manually so the curves would be right. The strings are splines with Spline Dynamics hair tags applied, and the balls are attached using XPresso, they move with the string (you’d think it’d be the other way around, but I couldn’t make it work). What I want to be able to do is have the starting ball fall, thus making the other end ball go up. This is basic physics, it’s kinetic energy transferring through the balls til it can’t anymore, making the end ball go up. Am I right in assuming that it would be as simple as just applying rigib body dynamics to each ball, setting collisions, and letting it go? That seems to simple, I just know that there will be XPresso involved. Anyways, can someone point me in the right direction please, I really would like to actually finish this one project.
Thank you.
-
5 Replies
-
Bump, sorry for the double post, but I’d really like to try getting this to work without borking it up trying rigid body dynamics and having it not work. I’d rather start with a good knowledge of what I’ll need to do, then figure it out from there, then try to blindly throw it together. I’m sure I did this completely wrong, it seems like I have a LOT of objects in the OM. I have a group with 5 sweep nurbs with a .25m radius circle along the splines to make the strings. I have the 5 balls in a group, I have the frame for the thing, the floor, the 2 lights (they weren’t on in the picture in the first post), the targets for those lights, and the null object where I put all the XPresso for the “strings”. It seems like too much.
Anyways, I’d love to animate this nd make it dynamic, swinging back and forth, but I just don’t know how, please help, someone.
-
This is sort of right. It’s a fake of the physics using the y position of a null following a circle spline mapped to the rotation of the end swings.
It does not decay but that could be done by reducing the diameter of the circle spline over time or by substituting the circle for a helix spline that reduces diameter from start to end.
-
Could I not just use the real physics in the Rigid Body Dynamics? Would that work? I don’t know if C4D is advanced enough to transfer the energy like a real Newton’s Cradle works, though. If it does, then I could potentially do this, right? Will something move something else that it hits? Like if I had a ball laying on the ground, and I dropped another ball on top of it, would the ball on the ground move?
-
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?
-
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?
Reply to this Discussion! Login or Sign Up