# Wrecking Ball Constraint Question

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Hi!

I've setup a simple scene with a wrecking ball with a chain hitting a brick wall. I've two constraints network a hard constraint that takes cares of most things and then a glue network that keeps the ball together (it's made up from two pieces). The brick just sits on each other and contains no constraints.

Everything seems to work fine from the exception that the hard constraints starts to stretch (ie the chain starts to stretch) when the mass of the ball becomes too high.

The only way I found to get around this is to increase the density of the chain to 10 times the ball. But it just doesn't look alright.

Is there another constraint I should use instead of the hard constraint or is there a way I can increase the strength of the hard constraint without increasing the mass of the chain?

Thanks!

/ John

WreckingBall_Constraints_V01_01.hipnc

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When working with large forces and stiff constraints, just increasing the stepping tends to make things behave better.

Increasing the bullet substeps and constraint substeps from 10 to 20 on the solver, but reducing the chain density from 10000 to 1000 seems to work quite fine.

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That did work fine, big thanks as always eetu!

Are there any constraint better suited for a task like that (stiff chain) than the hard constraint?

And if I understand correctly there are no way to specifically increase the strength of the hard constraint because it always tries to hold everything in the correct position?

When I increased the density of my chain the hard constraint did a better job holding the chain and the ball together, there are no way to cheat this without having a denser chain than ball? On the other hand it does work a lot better now with more substeps and constraints iterations.

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Are there any constraint better suited for a task like that (stiff chain) than the hard constraint?

And if I understand correctly there are no way to specifically increase the strength of the hard constraint because it always tries to hold everything in the correct position?

Yes, increasing iterations/substeps results in a much stiff/stable constraints.

You can also use combination of glue/hard constraints holding the same pieces to make pieces behave less springy.

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Ok! Thanks for that tip

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