[Anna]

Thanks for your answer Ugo,

Working with a thinner resolution of my hexa might be a trick then.

[Anna]

Hi @noura,

I actually implemented the same thing using my own component but I then came across collision issues. Indeed, in a simple scene with a deformable object and an moving obstacle, collisions are not handled correctly but they are if my obstacle is fixed.

Did you came across such a problem?

[Anna]

Hi,

Regarding the source, applyTranslation and applyRotation seem to apply your delta directly to the positions so that should work in your case.

[Anna]

Hi Hugo,

Thanks for you answer.

Here is an example using the sphere.obj found in the share/mesh/ directory.

<?xml version="1.0"?>
<Node 	 name="root"  gravity="0 -10 0"  animate="0"  >
	<VisualStyle displayFlags="showBehaviorModels showForceFields showCollisionModels" />
	<DefaultPipeline name="Collision Pipeline" />
	<BruteForceDetection name="Detection" />
	<MinProximityIntersection name="Proximity"  alarmDistance="0.3"  contactDistance="0.2" />
	<DefaultContactManager name="Contact Manager"  response="default" />
	<DefaultCollisionGroupManager name="Collision Group Manager" />
	<DefaultAnimationLoop name="defaultAnimationLoop" />
	<Node 	 name="Simulation"  gravity="0 -10 0"  dt="0.01"  time="0"  animate="0"  >
		<EulerImplicitSolver name="Euler Implicit" />
		<CGLinearSolver template="GraphScattered" name="Conjugate Gradient"  iterations="25"  tolerance="1e-05"  threshold="1e-05" />
		<MeshObjLoader name="loader" filename="/tmp/sphere.obj" />
		<SparseGridTopology name="SparseGrid Topology" fileTopology="/tmp/sphere.obj" n="5 5 5" />
		<MechanicalObject template="Vec3d" name="Particles"/>
		<UniformMass template="Vec3d" mass="1" />
		<HexahedronFEMForceField template="Vec3d" name="HexahedronFEM Forcefield" poissonRatio="0.45"  youngModulus="200"  gatherPt=" "  gatherBsize=" " />
		<FixedConstraint template="Vec3d" name="BehaviorConstraints"  indices="72 73 97 98" />
		<Node 	 name="Collision"  gravity="0 -10 0"  dt="0.01"  time="0"  animate="0"  >
			<MeshTopology position="@../loader.position"triangles="@loader.triangles"  quads="@loader.quads"  tetrahedra="@loader.tetras"  hexahedra="@loader.hexas" />
			<MechanicalObject template="Vec3d" name="CollisionObject" />
			<TTriangleModel template="Vec3d" name="TriangleCollision"  moving="1"  simulated="1"  color="1 0.5 0 1" />
			<TLineModel template="Vec3d" name="LineCollision"  moving="1"  simulated="1"  color="1 0.5 0 1" />
			<TPointModel template="Vec3d" name="PointCollision"  moving="1"  simulated="1"  color="1 0.5 0 1" />
			<BarycentricMapping template="Vec3d,Vec3d" name="MechanicalMapping"  input="@/Simulation/Particles"  output="@CollisionObject" />
			<!-- <FixedConstraint template="Vec3d" name="CollisionConstraints" indices= "317 335 336 337 338 339 340 355 356 357 358 359 360 375 376 377 378 379 380 382
" /> -->
		</Node>
	</Node>
</Node>

If you uncomment the CollisionConstraints fixed constraint and comment the BehaviorConstraints, you’ll get the difference. I was expecting that the fixed points of the collision model remain fixed.

Am I missing something?

[Author]

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