Issues with tearing Using the tearing plugin

[dhananjayjha100]

I am tring to build a simualtion that involves a triangular mesh incision using a tool with haptic feedback. The problem is that the tearing is not happening as expected. The goal is that the tearing should happen at the point where the tool is trying to pierce it(like creating a hole ), but it is happening at some other point as shown in the video.

test_cutting.mp4

I am getting the force feedback as expected, but the issue is with tearing and stability. Whenever the tearing happens I also get these warnings:

[WARNING] [DiagonalMass(DiagonalMass1)] MOVED topology event not handled on  (it should not even exist!)
[WARNING] [FixedConstraint(fixedConstraint1)] MOVED topology event not handled on  (it should not even exist!)
[WARNING] [FixedConstraint(fixedConstraint4)] MOVED topology event not handled on  (it should not even exist!)
[WARNING] [FixedConstraint(fixedConstraint2)] MOVED topology event not handled on  (it should not even exist!)
[WARNING] [FixedConstraint(fixedConstraint3)] MOVED topology event not handled on  (it should not even exist!)
[WARNING] [OglModel(visu)] MOVED topology event not handled on  (it should not even exist!)
[WARNING] [DiagonalMass(DiagonalMass1)] MOVED topology event not handled on  (it should not even exist!)
[WARNING] [FixedConstraint(fixedConstraint1)] MOVED topology event not handled on  (it should not even exist!)
[WARNING] [FixedConstraint(fixedConstraint4)] MOVED topology event not handled on  (it should not even exist!)
[WARNING] [FixedConstraint(fixedConstraint2)] MOVED topology event not handled on  (it should not even exist!)
[WARNING] [FixedConstraint(fixedConstraint3)] MOVED topology event not handled on  (it should not even exist!)
[WARNING] [OglModel(visu)] MOVED topology event not handled on  (it should not even exist!)

Here is the scene file:

<?xml version="1.0" ?>
<Node name="root" dt="0.009" gravity="0 0 0" >
    <RequiredPlugin name="Geomagic"/> <!-- Needed to use components [GeomagicDriver] -->
    <RequiredPlugin name="Sofa.Component.AnimationLoop"/> <!-- Needed to use components [FreeMotionAnimationLoop] -->
    <RequiredPlugin name="Sofa.Component.Collision.Detection.Algorithm"/> <!-- Needed to use components [BVHNarrowPhase BruteForceBroadPhase CollisionPipeline] -->
    <RequiredPlugin name="Sofa.Component.Collision.Detection.Intersection"/> <!-- Needed to use components [LocalMinDistance] -->
    <RequiredPlugin name="Sofa.Component.Collision.Geometry"/> <!-- Needed to use components [LineCollisionModel PointCollisionModel SphereCollisionModel] -->
    <RequiredPlugin name="Sofa.Component.Collision.Response.Contact"/> <!-- Needed to use components [CollisionResponse] -->
    <RequiredPlugin name="Sofa.Component.Constraint.Lagrangian.Correction"/> <!-- Needed to use components [PrecomputedConstraintCorrection UncoupledConstraintCorrection] -->
    <RequiredPlugin name="Sofa.Component.Constraint.Lagrangian.Solver"/> <!-- Needed to use components [LCPConstraintSolver] -->
    <RequiredPlugin name="Sofa.Component.Constraint.Projective"/> <!-- Needed to use components [FixedConstraint] -->
    <RequiredPlugin name="Sofa.Component.Controller"/> <!-- Needed to use components [MechanicalStateController] -->
    <RequiredPlugin name="Sofa.Component.Haptics"/> <!-- Needed to use components [LCPForceFeedback] -->
    <RequiredPlugin name="Sofa.Component.IO.Mesh"/> <!-- Needed to use components [MeshGmshLoader MeshOBJLoader SphereLoader] -->
    <RequiredPlugin name="Sofa.Component.LinearSolver.Iterative"/> <!-- Needed to use components [CGLinearSolver] -->
    <RequiredPlugin name="Sofa.Component.Mapping.Linear"/> <!-- Needed to use components [BarycentricMapping] -->
    <RequiredPlugin name="Sofa.Component.Mapping.NonLinear"/> <!-- Needed to use components [RigidMapping] -->
    <RequiredPlugin name="Sofa.Component.Mass"/> <!-- Needed to use components [DiagonalMass UniformMass] -->
    <RequiredPlugin name="Sofa.Component.ODESolver.Backward"/> <!-- Needed to use components [EulerImplicitSolver] -->
    <RequiredPlugin name="Sofa.Component.SolidMechanics.FEM.Elastic"/> <!-- Needed to use components [TetrahedronFEMForceField] -->
    <RequiredPlugin name="Sofa.Component.SolidMechanics.Spring"/> <!-- Needed to use components [VectorSpringForceField] -->
    <RequiredPlugin name="Sofa.Component.StateContainer"/> <!-- Needed to use components [MechanicalObject] -->
    <RequiredPlugin name="Sofa.Component.Topology.Container.Constant"/> <!-- Needed to use components [MeshTopology] -->
    <RequiredPlugin name="Sofa.Component.Topology.Container.Grid"/> <!-- Needed to use components [RegularGridTopology] -->
    <RequiredPlugin name="Sofa.Component.Topology.Container.Dynamic"/> <!-- Needed to use components [TetrahedronSetGeometryAlgorithms TetrahedronSetTopologyContainer] -->
    <RequiredPlugin name="Sofa.Component.Topology.Mapping"/> <!-- Needed to use components [Quad2TriangleTopologicalMapping] -->
    <RequiredPlugin name="Sofa.Component.Visual"/> <!-- Needed to use components [VisualStyle] -->
    <RequiredPlugin name="Sofa.GL.Component.Rendering3D"/> <!-- Needed to use components [OglModel] -->
    <RequiredPlugin name="Sofa.Component.Engine.Select"/> <!-- Needed to use components [BoxROI] -->
    <RequiredPlugin name="Sofa.Component.LinearSolver.Direct"/> <!-- Needed to use components [SparseLDLSolver] -->
    <RequiredPlugin name="Sofa.Component.SceneUtility"/> <!-- Needed to use components [InfoComponent] -->
    <RequiredPlugin name="tearing"/>

    <VisualStyle displayFlags=""/>
    
    <FreeMotionAnimationLoop/>
    <GenericConstraintSolver resolutionMethod="UnbuildGaussSeidel"   tolerance="1e-8" maxIt="500"/>
    <CollisionPipeline depth="6" verbose="0" draw="0"/>
    <BruteForceBroadPhase/>
    <BVHNarrowPhase/>
    <LocalMinDistance name="Proximity" alarmDistance="0.5" contactDistance="0.1" angleCone="0.0"/>
    <DefaultContactManager name="Response" response="FrictionContactConstraint"/>
    <LCPConstraintSolver tolerance="0.001" maxIt="1000"/>
    <GeomagicDriver name="GeomagicDevice" deviceName="Default Device" scale="1" drawDeviceFrame="1" positionBase="0 0 0" drawDevice="0" orientationBase="0 0.707 0 -0.707"  />
    <DefaultVisualManagerLoop />
	<RegularGridTopology name="grid" n="1 20 20" min="0 0 0" max="0 10 10" />

    <Node name="TriangularFEMForceField">
        <EulerImplicitSolver name="cg_odesolver" printLog="false"  rayleighStiffness="0.1" rayleighMass="0.1" />
        <!-- <CGLinearSolver iterations="25" name="linear solver" tolerance="1.0e-10" threshold="1.0e-12" /> -->
        <SparseLDLSolver template="CompressedRowSparseMatrixMat3x3d" name="Torus1_SparseLDLSolver" printLog="false" />
        
        <MechanicalObject name="tissue_dofs" src="@../grid"/>
        
        <TriangleSetTopologyContainer name="Triangle_topo" src="@../grid"/>
        <TriangleSetTopologyModifier name="Modifier" />
        <TriangleSetGeometryAlgorithms name="GeomAlgo" template="Vec3d" />
        
        <DiagonalMass massDensity="1.0" />
        
        <BoxROI template="Vec3d" name="box_roi1X" box="-0.1 -0.1 -0.1 0.1 10.1 0.1"/>
        <FixedConstraint template="Vec3d" name="fixedConstraint1" indices="@box_roi1X.indices"/>

        <BoxROI template="Vec3d" name="box_roi2X" box="-0.1 -0.1 9.9 0.1 10.1 10.1"/>
        <FixedConstraint template="Vec3d" name="fixedConstraint2" indices="@box_roi2X.indices"/>
        
        <BoxROI template="Vec3d" name="box_roi1Z" box="-0.1 -0.1 -0.1 0.1 0.1 10.1"/>
        <FixedConstraint template="Vec3d" name="fixedConstraint3" indices="@box_roi1Z.indices"/>
        
        <BoxROI template="Vec3d" name="box_roi2Z" box="-0.1 9.9 -0.1 0.1 10.1 10.1"/>
        <FixedConstraint template="Vec3d" name="fixedConstraint4" indices="@box_roi2Z.indices"/>

        <!-- <TriangularFEMForceField name="FEM" youngModulus="600" poissonRatio="0.3" method="large" computePrincipalStress="1"/>
        <TriangularBendingSprings name="FEM-Bend" stiffness="300" /> -->
      
        <TriangularFEMForceFieldOptim name="FEM" youngModulus="700" poissonRatio="0.35" method="large"/>
        <FastTriangularBendingSprings template="Vec3d" name="FEM-Bend"/>

        <TearingEngine name="TearingEngine" input_position="@tissue_dofs.position" stressThreshold="7.0" 
            step="3" nbFractureMax="30" showFracturePath="1" fractureMaxLength="5.0" showTearableTriangle="1"/>
            
        <TriangleCollisionModel  bothSide="1"/>
        <LineCollisionModel  bothSide="1"/>
        <PointCollisionModel  bothSide="1"/>
        <!-- <UncoupledConstraintCorrection/>  -->
        <LinearSolverConstraintCorrection/>
        <Node name="Visu">
            <OglModel name="visu" color="red" />
            <IdentityMapping name="mapping" input="@.." output="@." />
        </Node>
    </Node>

    <!-- ADDED: the Mechanical state Controller gathers events from the Omni driver and populates the Mechanical state -->
    <Node name="Omni">
        <MechanicalObject template="Rigid3" name="DOFs" position="@GeomagicDevice.positionDevice"/>
    </Node>
	
	<Node name="Instrument" >
        <EulerImplicitSolver rayleighMass="0.01" rayleighStiffness="0.1" />
		<SparseLDLSolver template="CompressedRowSparseMatrixMat3x3d"/>
        <!-- <CGLinearSolver iterations="25" tolerance="1e-5" threshold="1e-5"/> -->
        
		<MechanicalObject name="instrumentState" template="Rigid3" tags="GeomagicDevice" />
		<UniformMass name="mass" totalMass="10" />
		
		<RestShapeSpringsForceField stiffness='1000000' angularStiffness='1000000' external_rest_shape='@../Omni/DOFs' points='0' external_points='0'/>
        <LCPForceFeedback name="LCPFF1" activate="true" forceCoef="0.01"/> 
        <!-- <UncoupledConstraintCorrection compliance="0.001   0.00003 0 0   0.00003 0   0.00003" /> -->
        <LinearSolverConstraintCorrection/>
		
		<Node name="VisuTool" >
            <MeshOBJLoader name="meshLoader_1" filename="Demos/Dentistry/data/mesh/dental_instrument.obj" handleSeams="1" />
            <OglModel name="InstrumentVisualModel" src="@meshLoader_1" color="1.0 0.2 0.2 1.0"  ry="180" rz="-90" dz="3.5" dx="-1.0"/>
            <RigidMapping name="MM->VM mapping" input="@instrumentState" output="@InstrumentVisualModel" />
        </Node>
		
        <Node name="CollisionModel" >
            <MeshOBJLoader filename="Demos/Dentistry/data/mesh/dental_instrument.obj"  name="loader"/>
            <MeshTopology src="@loader" name="InstrumentCollisionModel" />
            <MechanicalObject src="@loader" name="instrumentCollisionState"  ry="180" rz="-90" dz="3.5" dx="-1.0" />
            <LineCollisionModel />			
            <PointCollisionModel />
            <RigidMapping name="MM->CM mapping" input="@instrumentState" output="@instrumentCollisionState" />		
        </Node>
    </Node> 
    
</Node>

Please help me in this problem.
Thanks.

[hugtalbot]

Hi @dhananjayjha100

Thanks for your question. The Tearing plugin is developed by the InfinyTech3D company offering custom development and services around SOFA. I do not know very well this part of the code.

It seems to me that your simulation is pretty slow while the haptic moves at high rates. I guess this can already be a source of instability at the collision detection level. Maybe @epernod could tell more about it.

Could you tell us more about your simulation background and objectives ?
Cutting and tearing are complex topics. Do not hesitate to get in touch with InfinyTech3D.
Cheers

[dhananjayjha100]

Hi @hugtalbot,

Thanks for your quick response. Actually I am working on my academic project that involves surgical simulation, in which one part is the tearing of the membrane, which you can see in the provided video. The ultimate goal is to have a simulation effect similar to this. I hope this helps you to guide me in this specific issue.
Thanks.

[epernod]

Thank you for your feedback.
We also noticed the same issues with the tearing localization starting point and direction as well as the warning on MOVED event.
We are currently working on it with @rmolazem and will be back to you soon.

[dhananjayjha100]

Thanks a lot @epernod and @rmolazem.

[rmolazem]

Hi @dhananjayjha100,

Thank you for sharing your feedback with us. I'm pleased to inform you that we've addressed the issue regarding the selection of the starting vertex for tearing. Now, we provide three different methods for choosing the starting vertex. You can refer to the tearing plugin documentation for more detailed information on these methods.
We recommend updating your local version and rerunning your simulation to take advantage of these improvements. If you encounter any further issues or have additional questions, feel free to reach out to us.

Have a good day!

[dhananjayjha100]

Thanks a lot, @rmolazem and @epernod, for making these improvements and providing detailed documentation. Now the tearing is happening as expected. Unfortunately, I encountered one more issue: in the visualization part of the tearing engine component, whenever I unchecked the options showTearableTriangle and showFracturePath, tearing doesn't happen.

[rmolazem]

Thank you for your feedback. Note that the occurrence of tearing isn't influenced by the visualization settings. In the current
version of the plugin, you should be able to view the fracture segment and the potential triangle to start the fracture (of course in the case if the fracture happens ). If you want you may share your scene file or only the lines related to TearingEngine's data. So that we know your setting to provide a possible solution.

Additionally, we're currently implementing a new method for building the fracture segment, so there are ongoing modifications. To ensure stability for now, we recommend setting a non-zero value for "fractureMaxLength" in the scene file. This will allow the simulation to use the stable method of building the fracture segment.

Best,
InfinyTech3D

[github-actions[bot]]

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@dhananjayjha100
Feedback has been given to you by the project reviewers, however we have not received a response from you. Without further news in the coming weeks, this discussion will be automatically closed in order to keep this forum clean and fresh 🌱 Thank you for your understanding

[github-actions[bot]]

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@dhananjayjha100
In accordance with our forum management policy, the last reply is more than 4 months old and is therefore closed. Our objective is to keep the forum up to date and offer the best support experience.

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