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Constraint FEM


oslo

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there is a bug with the FEM solver and the spring constraint relationship node in h14 (in h13 this node worked well) but you could use the cloth attach constraint .but with the cloth attach constraint doesnt have rest length asttribute so its not a true replacement for the spring relationship node . Hopefully this bug will be fixed on H15  .  

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I've used soft body constraints in H13, SBD set to soft. I'll generate a selection volume for my tet meshes and use that to generate a softbody point constraint group. 

 

In Dops on the SBD constraint node you can a pointlist function to extract the group's contents into the node. eg. 'pointlist("../../group1","groupName")`

 

I'm using a static tet mesh which is being deformed by a point lattice operation as the simulation input. That way I get a animated "rest state" for my FEM that is stable. Make sure you are importing the rest and target geometry so that FEM knows its dealing with an animated tetmesh, then you'll get something that SBD constraint will work with. After that it's playing with the values, number of nets, etc to get something that works nicely.

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I've used soft body constraints in H13, SBD set to soft. I'll generate a selection volume for my tet meshes and use that to generate a softbody point constraint group. 

 

In Dops on the SBD constraint node you can a pointlist function to extract the group's contents into the node. eg. 'pointlist("../../group1","groupName")`

 

I'm using a static tet mesh which is being deformed by a point lattice operation as the simulation input. That way I get a animated "rest state" for my FEM that is stable. Make sure you are importing the rest and target geometry so that FEM knows its dealing with an animated tetmesh, then you'll get something that SBD constraint will work with. After that it's playing with the values, number of nets, etc to get something that works nicely.

the sbd constraint worked fine on houdini 13 but in houdini 14 the sbd constraint only works on "hard mode" 

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  • 1 year later...

@mattfx: the sbd constraint worked fine on houdini 13 but in houdini 14 the sbd constraint only works on "hard mode" 

 

I am still seeing this behaviour in 16. Dos the soft constraint method need something else to make it work. As dialling up the strength to 100000000+ does nothing. Constraints go red and are ineffectual.

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