How would you implement a grid resolution factor?

[streunerlein]

Hello @keijiro !

Thank you for this amazing implementation. One question arose while we've tried it, how would you implement a grid resolution parameter as in Paul Bourke's article to steer the resolution of the mesh? By just increasing sampling distances in the volume?

Greetings

Dominique

PS: Talking about this

My first guess would be the increase the sampling in the MeshConstruction shader from:

[numthreads(4, 4, 4)]
void MeshReconstruction(uint3 id : SV_DispatchThreadID)
{
    // Boundary check
    if (any(id + 1 >= Dims.xyz)) return;

    // Voxel samples at each cube vertex
    float4 samples[8];
    for (uint i = 0; i < 8; i++)
        samples[i] = VoxelValueWithGradient(id + CubeVertex(i));

// ...
}

to something like

uint samplingDistance;

[numthreads(4, 4, 4)]
void MeshReconstruction(uint3 id : SV_DispatchThreadID)
{
    id = id * samplingDistance;
    // Boundary check
    if (any(id + 1 >= Dims.xyz)) return;

    // Voxel samples at each cube vertex
    float4 samples[8];
    for (uint i = 0; i < 8; i++)
        samples[i] = VoxelValueWithGradient(id + CubeVertex(i));

// ...
}

and modifying the threadgroups by this samplingDistance:

   int samplingDistance = 1;
    void RunCompute(ComputeBuffer voxels, float target, float scale)
    {
        _counterBuffer.SetCounterValue(0);

        var downSampledGrids = new Vector3Int(_grids.x / samplingDistance, _grids.y / samplingDistance, _grids.z / samplingDistance);

        // Isosurface reconstruction
        _compute.SetInt("samplingDistance", samplingDistance);
        _compute.SetInts("Dims", downSampledGrids );
        _compute.SetInt("MaxTriangle", _triangleBudget);
        _compute.SetFloat("Scale", scale);
        _compute.SetFloat("Isovalue", target);
        _compute.SetBuffer(0, "TriangleTable", _triangleTable);
        _compute.SetBuffer(0, "Voxels", voxels);
        _compute.SetBuffer(0, "VertexBuffer", _vertexBuffer);
        _compute.SetBuffer(0, "IndexBuffer", _indexBuffer);
        _compute.SetBuffer(0, "Counter", _counterBuffer);
        _compute.DispatchThreads(0, downSampledGrids );

        // Clear unused area of the buffers.
        _compute.SetBuffer(1, "VertexBuffer", _vertexBuffer);
        _compute.SetBuffer(1, "IndexBuffer", _indexBuffer);
        _compute.SetBuffer(1, "Counter", _counterBuffer);
        _compute.DispatchThreads(1, 1, 1, 1);

        // Bounding box
        var ext = new Vector3(_grids.x, _grids.y, _grids.z) * scale;
        _mesh.bounds = new Bounds(Vector3.zero, ext);
    }

[keijiro]

Sorry, I can't understand your point. Isn't it just increasing dimensions count?

[streunerlein]

Does this also work for Volumes (instead of noise)? That's our case we are trying to solve right now (VolumeDataVisualizer.cs)

[keijiro]

You should increase the resolution of the volume data (I think that's what the author said in the article).

[keijiro]

I'm closing this issue now. Please reopen it for further problems.