Video: Dynamica Rope Test

[mBakr]

Here is a first test of falling rope sim'd with Dynamica. 1000 rigid body spheres are connected in a chain-like series with 6Dof constraints.

http://vimeo.com/18769422

[RBD]

Very nice.
I tried that a while ago, but when I textured the "rope" I couldn't get it to roll around correctly... surface would get all twisted. May I ask how your "rope" surface is connected to the sphere's rotation? ...Hmmm, I guess you simply put limits on the 6dof rotations? (seems pretty obvious to me now )

[RBD]

BTW, mBakr, if you're curious I tried it using capsule primitives instead and it works very well, see in this video (not the first test anims, more near the middle, also real-time demo near the end):
http://www.youtube.com/watch?v=i1YIafaqF7A

p.s.: I also remembered that when I tried with Dynamica, at that time there was only the ball constraint, which explains the twisting. (don't have access to Maya anymore, which is why I'm using Blender now.)

[Erwin Coumans]

Beautiful videos, both the Maya and Blender one.

Do you guys mind sharing the (zipped) Maya and Blender file?
Thanks!
Erwin

[mBakr]

RBD!

nice capsule tests. I started with both Blender and Maya in 1998. I haven't spent much time with Blender in the past couple years, but I miss the speedy workflows and python API.

To answer your question about the rope, I added a Paint Effect stroke to the curve that is controlled by the spheres - pfx strokes are easier to "disentangle" than the standard extrudes in Maya...

btw, you can get a free student license for Maya if you have a student email address...

[goldleaf]

Great tests! Are there scenes available? RBD, are you planning to release your python tools?

Thanks for sharing!

[mBakr]

Attached is a maya scene file containing a dynamica rope demo. The scene was built in Maya 2011, but should be compatible with older versions (check 'ignore version' when opening the file). Ensure that the Dynamica plugin is loaded, then open the scene and press play. the stiffness of the rope can be adjusted by changing the upper angle limits on the 6dof constraints (in the dConsraints group - select them all and change the values in the channel box to modify all constraints) - lower values == stiffer rope.

I am planning to build the rope creation tools into Dynamica for a later release, but a preview script is attached. You will need the latest Dynamica constraint tools to generate the constraint chain between the rigid bodies. Find the tools here:
http://bulletphysics.org/Bullet/phpBB3/ ... =12&t=6134

have fun.