tools::PointsToVolume

[uhlong]

Hi guys,

    I am looking for a tool, which is shown in "TopologyToLevelSet.h", to convert points to volume, but I haven't found it. Does anyone know where the API is or any suggestion to realize such function. Thank you in advance.

    Regards.

[Pavel Geraskin]

I searched this example on the internet  too   but I failed.  OpenVDB is too hardcore for newbies like me.   May I suggest  openvdb::tools::ParticlesToLevelSet ? 
I found these 2 examples :

https://blog.csdn.net/weixin_34402408/article/details/94278143

https://developer.blender.org/F23586

All you need is just points positions. My simple code was like this:

[code]

struct MyParticle

{

    openvdb::Vec3R p, v;

    openvdb::Real  r;

};

class MyParticleList {

public:

    openvdb::Real           mRadiusScale;

    openvdb::Real           mVelocityScale;

    std::vector<MyParticle> mParticleList;

  typedef openvdb::Vec3R  PosType;

    MyParticleList(openvdb::Real rScale=1, openvdb::Real vScale=1)

            : mRadiusScale(rScale), mVelocityScale(vScale) {}

    void add(const openvdb::Vec3R &p, const openvdb::Real &r,

             const openvdb::Vec3R &v=openvdb::Vec3R(0,0,0))

    {

        MyParticle pa;

        pa.p = p;

        pa.r = r;

        pa.v = v;

        mParticleList.push_back(pa);

    }

  // Return the total number of particles in list.

  // Always required!

  size_t size() const { return mParticleList.size(); };

  // Get the world space position of the nth particle.

  // Required by ParticledToLevelSet::rasterizeSphere(*this,radius).

  void getPos(size_t n, openvdb::Vec3R& pos) const { pos = mParticleList[n].p; };

  // Get the world space position and radius of the nth particle.

  // Required by ParticledToLevelSet::rasterizeSphere(*this).

  void getPosRad(size_t n,  openvdb::Vec3R& pos, openvdb::Real& rad) const {

      pos = mParticleList[n].p;

      rad = mRadiusScale*mParticleList[n].r;

  };

  // Get the world space position, radius and velocity of the nth particle.

  // Required by ParticledToLevelSet::rasterizeSphere(*this,radius).

  void getPosRadVel(size_t n, openvdb::Vec3R& pos, openvdb::Real& rad, openvdb::Vec3R& vel) const {

      pos = mParticleList[n].p;

      rad = mRadiusScale*mParticleList[n].r;

      vel = mVelocityScale*mParticleList[n].v;

  };

  // Get the attribute of the nth particle. AttributeType is user-defined!

  // Only required if attribute transfer is enabled in ParticlesToLevelSet.

  void getAtt(size_t n, openvdb::Index32& att) const { att = openvdb::Index32(n); };

};

int main(int argc, char *argv[])

{

    openvdb::initialize();

....... SOME CODE ......

// VDB transform openvdb::math::Transform::Ptr xform = openvdb::math::Transform::createLinearTransform(0.01);

    MyParticleList pa(1,1);

    for (openvdb::Vec3s pos : vertices) {

        pa.add(openvdb::Vec3R( pos[0],  pos[1],  pos[2]), 0.1, openvdb::Vec3R( 0, 0, 0));

    }

    openvdb::FloatGrid::Ptr densityGrid = openvdb::createLevelSet<openvdb::FloatGrid>(vdb_voxel_size, 3);

    std::cout << "set density grid";

    densityGrid->setGridClass(openvdb::GRID_LEVEL_SET);

    densityGrid->setTransform(xform);

    densityGrid->setName("density");

    openvdb::tools::ParticlesToLevelSet<openvdb::FloatGrid> raster(*densityGrid);

    raster.rasterizeSpheres(pa);

    raster.finalize(true);

    //openvdb::FloatGrid::Ptr grid = densityGrid;  // TEST!!!!!!

}

[/code]  

понедельник, 7 декабря 2020 г. в 10:35:34 UTC+3, uhlong:

[uhlong]

Hi Pavel, thanks for sharing.