[SOLVED] Apply a visual (.stl) on a beam

[Alex]

Hello,

I would like to add a visual model on a beam
To do so i’ve initially created an object:
model.createObject('MeshSTLLoader', name='surface', filename=#)

Then the MechanicalObject of the beam :
model.createObject('MechanicalObject', template='Rigid3d', name='frame1', position=#)

And finally the link between my visual and the beam :

visu = model.createChild('visu')
visu.createObject('OglModel', name='VisualModel', src='@../surface')
visu.createObject('IdentityMapping', input='@../frame1', output='@VisualModel')

But my result is not has expected :

I should have a curved cylinder but instead the mesh seems to be all messed up
I’ve also tried with “RigidMapping” without success
What did I miss ?

Regards,

[Hugo]

Hi @alexftw

Could you replace with a RigidMapping instead?
RigidMapping links Rigid3d (beam) and any other type like Vec3d (OglModel).

I hope this helps

Hugo

[Alex]

Hello @Hugo ,

This is the result with ‘RigidMapping’ :

The mesh doesn’t follow the beam

Regards,

[Hugo]

Hi @alexftw

Beams are different than usual Rigid object.
Could you use the BeamLinearMapping instead? I should have pointed it out in the first place.

Best,

Hugo

[Alex]

Hello @Hugo
It’s getting closer but still not good, maybe is there something wrong with the way I’ve created my beam ?
Result :

The beam :

model = solverNode.createChild('model')
model.createObject('MeshSTLLoader', name='surface', filename='mesh/#.stl')
model.createObject('Mesh', name="meshBeam", position=#, lines=#)
model.createObject('MechanicalObject', template='Rigid3d', name='frame1', position=#, printLog=0, translation="0 0 0")
model.createObject('BeamInterpolation', dofsAndBeamsAligned='1', straight='1', defaultYoungModulus="1.8e18", radius=radius, name="interpolation")
model.createObject('AdaptiveBeamForceFieldAndMass',  name="BeamForceField", computeMass="1", massDensity="0.0001")
model.createObject('PartialFixedConstraint', indices='0', fixedDirections="1 1 1 1 1 1")
model.createObject('BoxROI', name='ROI1', box='5 10 2 -2 -2 2', drawBoxes='true')

Regards,

[Hugo]

Hi @alexftw

Sorry for the latency, I was away last week.
I think the mapping you are looking for has been implemented in a private plugin (plugin name: BeamAdapter, mapping name: BeamLinearMapping). I can try to get an access to this code for you.
Now some devs handle the rendering part in external tools like Unity.

Maybe @remibessard could help us here.

Best wishes,

Hugo

[epernod]

Hi,

I’m not expert in Rigid and RigidMapping but I think in your case you need to define which indices of your visual mesh is mapped to each rigid dof using the option rigidIndexPerPoint of the RigidMapping.

I think this scene is similar to what you want to do:
https://github.com/sofa-framework/sofa/blob/master/examples/Components/mapping/ArticulatedSystemMapping.scn

where a set of visual cube meshes are mapped on each rigid dof of the beam.

[remibessard]

Hi,

Agreed with @epernod, I would also precise these information to the RigidMapping when trying to make it work with this component.

As @Hugo mentionned I am using the BeamLinearMapping to map a collision model to a Beam model, but I think it is accessible in SOFA master without compiling any plugin.
Hope you can also find it and use it on your side.
(I have to say I am not mapping a volume into the beam (only a more discretized description of the same beam), so I don’t know if it will work with your visual volumetric model…)

As for me I use it that way in my scene configuration file:
endoCollNode.createObject('BeamLinearMapping', localCoord=False, applyRestPosition=True)
(feel free to play with these 2 parameters to fit your case)

Cheers,

Remi

[Alex]

Hello all,
I’m sorry I’ve completely forgot to answer here
This is the solution that have been given to me :

visuNode = model.createChild('visualization')
visuNode.createObject('CylinderGridTopology', name='topology', radius=radius, length='25', drawQuads='0', n='3 3 25', axis='1 0 0')
visuNode.createObject('MechanicalObject', name='test')
visuNode.createObject('AdaptiveBeamMapping', interpolation="@../interpolation", input="@../frame1", output="@test")

oglNode = visuNode.createChild('ogl')
oglNode.createObject('OglModel', color='0.2 0.2 0.2 1')
oglNode.createObject('IdentityMapping')

EDIT : Just noticed that this solution isn’t what I was asking for in my first post, maybe I should have not hit the ‘solved’ button ?

Thanks again!
Regards,
Alex

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