Cannot deform object using the mouse

[chz31]

Dear all,

I loaded a tetrahedron model and a visual model of an eye with muscles attached to it. However, I could not use the shift+left mouse click to use the spring force field or the bilateral interaction constraint to deform or displace the model. Below is my setting of the model:

    #mesh loader for msh
    meshLoaderCoarse = root.addObject('MeshGmshLoader', name='meshLoaderCoarse', filename='C:/Users/chi.zhang/Desktop/orbit_SOFA/soft_tissue-models/orbit_soft_tissue_down.msh', scale=10.0)
    meshLoaderFine = root.addObject('MeshOBJLoader', name='meshLoaderFine', filename='C:/Users/chi.zhang/Desktop/orbit_SOFA/soft_tissue-models/orbit_soft_tisue_vis.obj', scale=10.0)

    # Creating the falling sphere object
    plateNode = root.addChild("plate")
    # plateNode.addObject('MechanicalObject', name="mstate", template="Rigid3", translation2=[0., 0., 0.], rotation2=[0., 0., 0.], showObjectScale=50)

   # Creating the falling plateNode object
    plateNode.addObject('EulerImplicitSolver', name='odesolver')
    # plateNode.addObject('CGLinearSolver', name='Solver', iterations=25, tolerance=1e-05, threshold=1e-05)
    plateNode.addObject('SparseLDLSolver', name='Solver')
    
    #tetrahedron topology
    plateNode.addObject('TetrahedronSetTopologyContainer', name='topo', src=meshLoaderCoarse.getLinkPath())
    plateNode.addObject('TetrahedronSetGeometryAlgorithms', template='Vec3d', name='GeomAlgo')

    plateNode.addObject('MechanicalObject', template='Vec3d', name='MechanicalModel', showObject=True)
    plateNode.addObject('TetrahedronFEMForceField', name='FEM', youngModulus=1000, poissonRatio=0.47, method='large')
    plateNode.addObject('LinearSolverConstraintCorrection') #need for gravity filed #LinearSolverConstraint
    # plateNode.addObject('UncoupledConstraintCorrection', compliance=1e-9)
    plateNode.addObject('MeshMatrixMass', massDensity=1, topology='@topo')

    collision = plateNode.addChild('Collision')
    collision.addObject('MeshTopology', src=meshLoaderFine.getLinkPath())
    collision.addObject('MechanicalObject', name='CollisionMO')
    collision.addObject('TriangleCollisionModel', name='CollisionModel')
    collision.addObject('LineCollisionModel')
    collision.addObject('PointCollisionModel')
    collision.addObject('BarycentricMapping', name='CollisionMapping', input='@../MechanicalModel', output='@CollisionMO')


    # Fine visual model for plate with tetrahedron
    fineVisualModel = plateNode.addChild('FineVisualModel')
    fineVisualModel.addObject('OglModel', name='VisualModel', src=meshLoaderFine.getLinkPath())
    fineVisualModel.addObject('BarycentricMapping', name='Mapping', input='@../MechanicalModel', output='@VisualModel')

Here are my sample tetrahedron and obj file and the full script.

I also tried to use a simpler script for the liver model from SOFA tutorial to load the eye model with 'DefaultAnimationLoop' and 'UncoupledConstraintCorrection' and 'CGLLinearSolver':. Somehow it still did not work for my case, though it worked for the liver model from SOFA tutorial.

Could it be the problem with the tetrahedron models I used?

Thank you very much!

[thundermms]

I am very new to sofa aswell, and I have been recently trying to work with lagrangian solvers. Whatever I am suggesting is purely based on what I tried and I definitely think you should wait for the talented veterans of SOFA to help you in this, but I thought I would chip in, in the meantime. I had a similar issue as yours, these are the things I made that helped the model deform. (Again I am sorry if this didn't help)

1. Make sure you have a FreeMotionAnimationLoop
2. Make sure you have a solver like GenericConstraintSolver or LCPConstraintSolver
3. A contact Manager like this DefaultContactManager FrictionContactConstraint
4. each simulated object should also have its own ConstraintCorrection. So for me this was the important part that I missed when I wrote my code line. I did not add a compliance parameter initially and adding that helped deform the module. either a compliance or a default_compliance example
   soft_body.addObject('UncoupledConstraintCorrection', name="skin_ConstraintCorrection", defaultCompliance="0.01")
5. Also a BilateralInteractionConstraint between two deformable vec3d modules

[chz31]

@thundermms Thank you very much for your response and suggestions!

I did use a FreeMotionAnimationLoop and SparseLDLSolver and a LinearSolverConstraintCorrection. I also tried CGLLinearSolver and UncoupledConstraintCorrection combo. Both sets can move the object by gravity, but they could not deform the object.

I also felt a bit weird that I tried CGLLinearSolver and simply the DefaultAnimationLoop following the long youtube tutorial, which could deform the liver model from sofa/mesh/ folder. However, when I switched the liver model with my obj and msh, everything just stopped working. The model could not even been moved by constant force.

[chz31]

@thundermms Actually, I could deform the object while allowed it to move with gravity now by using SparseLDLSolver and a LinearSolverConstraintCorrection. It was because I scaled the coarse tetrahedron model and the fine visual model to 10 times to make it better visible

    meshLoaderCoarse = root.addObject('MeshGmshLoader', name='meshLoaderCoarse', filename='C:/Users/chi.zhang/Desktop/orbit_SOFA/soft_tissue-models/orbit_soft_tissue_down.msh', scale=10.0)
    meshLoaderFine = root.addObject('MeshOBJLoader', name='meshLoaderFine', filename='C:/Users/chi.zhang/Desktop/orbit_SOFA/soft_tissue-models/orbit_soft_tisue_vis.obj', scale=10.0)

After I adjusted scale = 1.0, the object became deformable. Thanks again!