Hi Cork City Gamelan,
If you like to have it all the time the same, use the cache and store the simulation.
Thanks a lot for the scene file. Always so much clearer to comment on.
Think of these calculations as a complex formula. Weight, Gravity, Torque, friction, bounce, inertia, etc
Each time there is a result, it describe one frame. From this frame the next calculation is done.
To do this in an manageable amount of time, things are as precise as needed. Let’s say for argument sake, the precision is 99.99%, (I assume it is lower). So the next time the frame has to work with a 99.99% times 99.99% precision.
This would equal 99.98001% or 99.98%. The precision is lowered with each frame. After your set up with 500 frames this little “error” will show.
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Not even to mention the Noise Collision Parameter, to keep things manageable—time wise, but it is certainly the most obvious factor here, besides my little excursion and build up values.
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A scientific correct simulation would perhaps plot a verification from the start parameters, to eliminate rounding errors and concatenate the parameters and situation based relations as far as possible to gain a high precision.
Well, that is not the scope here. The target is a rendering, not a game to play cars, even that is a lot of fun, I admit ;o)
I guess to have nearly 100% repeatable precision would take days on a single workstation, if at all possible on this kind of equipment.
Let’s have a look at your scene, the Friction and Bounce parameter look like to be set up with a 5% increment. This means this is your initial precision in a set up, to start with, the kind of expectation of precision shines here through, doesn’t it, not a proof that the rest could be sloppy, not my point here. I don’t blame here, it is just a simulation for visual representations and not a scientific based result, of a “super computer” repeatable at any place of the world.
So, my suggestion, if you like something keep the cache as is and save the scene. Bake perhaps the movement if that is critical. After baking, perhaps just with a Tracer and a Raid object, you can fine tune the expression, and that lands exactly in the filed of Cinema 4D, to create expressive images as an visual artist.
ENJOY