Organ simulation gets slow when fixed constraints are removed

[yangwxb]

I am now using sofa to do a simulation of software organization, I use fixed constraints to fix it in the scene, when the constraints disappear, I find that it moves very slowly, is there any way to improve it?

[epernod]

What do you mean by "constraints disappear" ?
do you have gravity in your scene and do the models have a mass?

[yangwxb]

"constraints disappear" means that I use a FixedConstraint component to fix the model initially, and then when I cancel the component, the model does not fall down, even if I pull the model, it moves slowly. (Gravity in the scene, mass in the model)

[hugtalbot]

Hi @yangwxb

I would recommend to check all your numerical settings (mechanical parameters, mesh quality&refinement, solvers settings).
Without your mesh it isn't possible to reproduce the simulation.

[yangwxb]

Thanks for your advice,hugtalbot.Can you help me see what's wrong with my script?

[epernod]

as @hugtalbot and @bakpaul mention. To properly help you, could you first post the entire scene script. Then a record of your behavior or a link to download the mesh to be able to execute your simulation would be useful as well.

[yangwxb]

This is my script:

<Node name="xuanrendai">
   
        <EulerImplicitSolver name="EulerImplicit"  rayleighStiffness="0.1" rayleighMass="0.15" />
        <CGLinearSolver name="CG Solver2" iterations="25" tolerance="1e-9" threshold="1e-25"/>
        <MeshGmshLoader filename="D:\unity\CataractSurgery\Assets\SofaUnity\Scenes\SofaScenes\mesh\XuanRenD.msh"  name="loader" scale3d="1 1 1"/>
        <MechanicalObject src="@loader" name="gong" rotation="-90 0 0" translation ="0 0.01 0"/>
        
        <!-- <FixedConstraint name="FixedConstraint" indices="157 130 153 244 227 209 192 174"/> -->
        
        <TetrahedronSetTopologyContainer  name="Tetra_topo" position="@gong.position" src="@loader"/>
		<TetrahedronSetTopologyModifier   name="Modifier" />
        <TetrahedronSetGeometryAlgorithms name="GeomAlgo" template="Vec3d" drawTetrahedra="0" drawScaleTetrahedra="0.8"/>

        
        
        <!-- <UniformMass totalMass="1"/> -->
        <DiagonalMass massDensity="10" />
        

        
        <TetrahedralCorotationalFEMForceField name="FEM" youngModulus="3000000" poissonRatio="0.3" method="large" />
        
       
		<UncoupledConstraintCorrection useOdeSolverIntegrationFactors="0"/>

        

        <Node name="Surface">
            
            <TriangleSetTopologyContainer  name="Container"/>
            <TriangleSetTopologyModifier   name="Modifier" />
            <TriangleSetGeometryAlgorithms name="GeomAlgo" template="Vec3d" drawTriangles="0"/>

            
            <Tetra2TriangleTopologicalMapping input="@../Tetra_topo" output="@Container" />

            
            <TriangularFEMForceField name="FEM" youngModulus="10000" poissonRatio="0.3" method="large" />
            
            <TriangularBendingSprings name="FEM-Bend" stiffness="50000" damping="1000.0" />
            

           
            <TriangleCollisionModel name="triangleCol" bothSide="true" group="1" tags="CarvingSurface" />
            <LineCollisionModel name='edgeCol' group="1" tags="CarvingSurface" />
            <PointCollisionModel name="pointCol" group="1" tags="CarvingSurface" />
            
            <Node name="Visua1">
                <OglModel name="Visualmode1" color = "red"/>
                <IdentityMapping input="@../../gong" output="@Visualmode1" />
            </Node>
        </Node>
    </Node>

[bakpaul]

If your scene is only constituted of this, without a root note with an animation loop it might be the cause...

[yangwxb]

<VisualStyle displayFlags="showVisual" />
<DefaultVisualManagerLoop />
<DefaultAnimationLoop/>
<DefaultPipeline verbose="0" depth="10" draw="0" />

<BruteForceBroadPhase/>
<BVHNarrowPhase/>
<!-- <DefaultContactManager response="PenalityContactForceField" /> -->
<DefaultContactManager response="PenalityContactForceField" />
<MinProximityIntersection name="Proximity" alarmDistance="0.0002" contactDistance="0.0001" />

<LCPConstraintSolver tolerance="0.001" maxIt="1000"/>

[yangwxb]

hi Paul, this is the component under my root node

[hugtalbot]

I insist on my reply

[github-actions[bot]]

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@yangwxb
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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@yangwxb
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