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Dear all,
Is there a way to break individual spring in meshSpring force field? I want to break it and remesh the model when the stress inside the spring is more then a specific value.
Thanks in advance.Hi Alison,
This is a very challenging project that you have here! Simulating deformable object is ok, with dynamic breaking of springs ok, but then do dynamic remeshing from the computation of the stress. It starts growing in term of complexity!
About how to break individual springs, you would need to create a component inheriting from meshSpringFF where you implement a function “removeSpring” doing the opposite than addSpring function (line 50 in meshSpringForceField.inl). You could then call this function when a specific event occurs.
We are currently working on dynamic remeshing based on VM stress as well. But this is really a on-going work. But I am no expert on the remeshing subject. @hpbui may be able to help ?
Cheers,
Hugo
Dear Alison,
If the topology of springs is within a ” topology container” like EdgeSetTopologyContainer for example, in order to break springs when their stress/strain exceed a threshold, you can simply use the removeEdges from EdgeSetTopologyModifier. Just after removal of the edge from your topology, you should propagate the change of the topology (by calling propagateTopologicalChanges() ) so that this change is taken into account in your force fields.
Hope these help.
Cheers,
PhuocDear Alison,
Dynamic topological change involves most parts of simulation. I am not an expert, here is what I think:
(1) First check if your forcefield support dynamic topological change. Is there a function “handleTopologicalChange” ? If not, you need to implement it.
(2) Need to call functions (e.g. removeTriangles, addTriangles…) in Modifier (e.g. TriangleSetTopologyModifier). These functions will call all handleTopologicalChange going down your scene graph. It will also change the mechanical state of your MechanicalObject.
(3) Some components did not handleTopologicalChange well by now, you need to check or modify them. For examples, adding points in OglModel troubles me a lot.regards,
Weng BinDear Jenny,
Did you read the comments of both Phuoc & Weng, just above.
I think they might be very useful to implement what you want.In case, you face any other problem, do no hesitate to describe it more specifically here (if the topics corresponds) or in a new topic!
Cheers,
Hugo
Dear Jenny,
We are letting this thread open for you, so that you can post any future question.
If you have any other question (unrelated to this topic), do not hesitate to create a new thread.
Best regards,Hugo
Dear Hugo and Jenny,
I’ve read the comments and found it kind of difficult for me to implement now, so I haven’t tried it either.
Thanks for your help! I will tell you as long as I solve it.Dear Alison & Jenny,
For topological changes, there is relatively easy way of dealing with it in SOFA. All you need is:
- a topology with a Container (e.g. EdgeSetTopologyContainer if you work with edges),
- and a topological modifier (e.g. EdgeSetTopologyModifier with edges).
Thus, you will be able to call the functions of the modifier to change the topology as you want.
There is unfortunately few examples in the public version of SOFA. In the code of the component VectorSpringForceField.inl (in modules/SofaDeformable/ at line 273) you have an example of edge removal. And the scene examples/Demos/TriangleSurfaceCutting.scn is a good example of topological changes (with right click and wheel click).
Hope this helps.
Best regards,Hugo
Dear @ywanling Alison,
It has been a long time.
Did you make it?
This thread is pretty old, I was wondering about closing it. Let us know about your progress.
Best,Hugo
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