Add deformable properties to SDF

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Original report (archived issue) by John Hsu (Bitbucket: hsu, GitHub: hsu).

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See discussion in notes.

Initially, this will be used by DART development.

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Original comment by John Hsu (Bitbucket: hsu, GitHub: hsu).

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cross reference paper by Jain and Liu

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Original comment by John Hsu (Bitbucket: hsu, GitHub: hsu).

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• changed state from "new" to "resolved"

done in https://bitbucket.org/osrf/dart_report/src/9e9b86ed931784038e4a2bd6234e8fbf94c14e3a/milestone_12/milestone.pdf?at=default#

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Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

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Should we mark this resolved when code has been committed? It looks like we just have a plan for implementation in that pdf.

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Original comment by John Hsu (Bitbucket: hsu, GitHub: hsu).

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• changed state from "resolved" to "open"

yes

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Original comment by John Hsu (Bitbucket: hsu, GitHub: hsu).

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Might consider scoping these under <dart>.

We should look at bullet softbody to see if the parameters overlap with current deformable properties proposal

<collision>
        <!-- Steve: we could also support simple shape types if we generate meshes automatically -->
        <geometry>
            <mesh>
                <path>C:/meshes/foot.obj</path>
            </mesh>
        </geometry>
        <surface>
                <!-- soft contact pamameters based on paper
        http://www.cc.gatech.edu/graphics/projects/Sumit/homepage/papers/sigasia11/jain_softcontacts_siga11.pdf
                -->
                <soft_contact>
                        <!-- kv in paper -->
                        <bone_attachment>100</bone_attachment>
                        <!-- ke in paper (can we make this parameter invariant to number of neighboring nodes? -->
                        <stiffness>100</stiffness>
                        <!-- damping of point velocity in body frame. -->
                        <damping>10</damping>
                        <!-- percent of mass to be distributed among deformable nodes -->
                        <flesh_mass_percentage>5</flesh_mass_percentage>
                </soft_contact>
        </surface>
</collision>

[osrf-migration]

Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

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I was just poking around the bullet soft body implementation, and I found a few parameters in btSoftBody.h:

/* Material   */ 
struct  Material : Element
{
  btScalar  m_kLST;   // Linear stiffness coefficient [0,1]
  btScalar  m_kAST;   // Area/Angular stiffness coefficient [0,1]
  btScalar  m_kVST;   // Volume stiffness coefficient [0,1]
  int  m_flags;       // Flags
};

[osrf-migration]

Original comment by John Hsu (Bitbucket: hsu, GitHub: hsu).

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pull request #78

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Original comment by John Hsu (Bitbucket: hsu, GitHub: hsu).

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pending how visualization is done, we may need to repeat some parameters in <visual>.

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Original comment by Dennis Leroy Wigand (Bitbucket: dlwigand).

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I am very much interested in the current status and how to contribute on this matter. Is there still progress going on?

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Original comment by Nate Koenig (Bitbucket: Nathan Koenig).

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There is currently no progress on this, and any contribution would be greatly appreciated. Let us know if you need help and/or guidance.