falling chain of rigid links

Hello!
I based on examples and created a small piece of the falling chain.
I encountered such a problem:
There is a chain consisting of four rigid links that fall on a rigid plane.
The second and third link, for some reason, suddenly merge. And this should not be, they must be repulsed.
I will be glad to any help and advice.
Thank you in advance!

Attachments:

falling chain.gh, 75 KB

Replies to This Discussion

Permalink Reply by Daniel Piker on November 30, 2017 at 8:42am

Hi,

I managed to improve the performance of the definition a little.

You don't need to input all the vertices of the mesh into the rigid body component unless you are using them for something else - so removing these speeds things up a bit.

Also shown is a simpler way of setting the collisions using the cross-reference component.

I tweaked the weightings a bit to try and improve the collision handling, but it is still a bit twitchy.

Collisions between complex concave geometry like this is tricky.

An alternative approach I think might work better here is to make use of the pipe-like geometry and use the line-line collisions instead. I'll make an example of this...

Attachments:

fallingchain2.gh, 74 KB

Permalink Reply by Daniel Piker on November 30, 2017 at 8:49am

Okay, here it is with just collision between line segments. It does seem to work much better than treating them as meshes.

Attachments:

FallingChainCollisions.gh, 24 KB

Permalink Reply by Alex Ts on November 30, 2017 at 12:05pm

Thank you, Daniel, for your prompt response to correct my difficulties!
The first option suits me better, for me it is important to determine the collision of figures with complex geometry that I get after retopology, chain links is a simplified version for example.
I need to use a grid, degrading the performance of the definition.
Thanks for the second version of the definition, using this, I updated MeshTools and found out about Weaverbird!

Excellent work, thank you!

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