public static void test_marching_cubes_demos()
{
// generateMeshF() meshes the input implicit function at
// the given cell resolution, and writes out the resulting mesh
Action <BoundedImplicitFunction3d, int, string> generateMeshF = (root, numcells, path) => {
MarchingCubes c = new MarchingCubes();
c.Implicit = root;
c.RootMode = MarchingCubes.RootfindingModes.LerpSteps; // cube-edge convergence method
c.RootModeSteps = 5; // number of iterations
c.Bounds = root.Bounds();
c.CubeSize = c.Bounds.MaxDim / numcells;
c.Bounds.Expand(3 * c.CubeSize); // leave a buffer of cells
c.Generate();
MeshNormals.QuickCompute(c.Mesh); // generate normals
StandardMeshWriter.WriteMesh(path, c.Mesh, WriteOptions.Defaults); // write mesh
};
// meshToImplicitF() generates a narrow-band distance-field and
// returns it as an implicit surface, that can be combined with other implicits
Func <DMesh3, int, double, BoundedImplicitFunction3d> meshToImplicitF = (meshIn, numcells, max_offset) => {
double meshCellsize = meshIn.CachedBounds.MaxDim / numcells;
MeshSignedDistanceGrid levelSet = new MeshSignedDistanceGrid(meshIn, meshCellsize);
levelSet.ExactBandWidth = (int)(max_offset / meshCellsize) + 1;
levelSet.Compute();
return(new DenseGridTrilinearImplicit(levelSet.Grid, levelSet.GridOrigin, levelSet.CellSize));
};
// meshToBlendImplicitF() computes the full distance-field grid for the input
// mesh. The bounds are expanded quite a bit to allow for blending,
// probably more than necessary in most cases
Func <DMesh3, int, BoundedImplicitFunction3d> meshToBlendImplicitF = (meshIn, numcells) => {
double meshCellsize = meshIn.CachedBounds.MaxDim / numcells;
MeshSignedDistanceGrid levelSet = new MeshSignedDistanceGrid(meshIn, meshCellsize);
levelSet.ExpandBounds = meshIn.CachedBounds.Diagonal * 0.25; // need some values outside mesh
levelSet.ComputeMode = MeshSignedDistanceGrid.ComputeModes.FullGrid;
levelSet.Compute();
return(new DenseGridTrilinearImplicit(levelSet.Grid, levelSet.GridOrigin, levelSet.CellSize));
};
// generate union/difference/intersection of sphere and cube
ImplicitSphere3d sphere = new ImplicitSphere3d()
{
Origin = Vector3d.Zero, Radius = 1.0
};
ImplicitBox3d box = new ImplicitBox3d()
{
Box = new Box3d(new Frame3f(Vector3f.AxisX), 0.5 * Vector3d.One)
};
generateMeshF(new ImplicitUnion3d()
{
A = sphere, B = box
}, 128, "c:\\demo\\union.obj");
generateMeshF(new ImplicitDifference3d()
{
A = sphere, B = box
}, 128, "c:\\demo\\difference.obj");
generateMeshF(new ImplicitIntersection3d()
{
A = sphere, B = box
}, 128, "c:\\demo\\intersection.obj");
// generate bunny offset surfaces
//double offset = 0.2f;
//DMesh3 mesh = TestUtil.LoadTestInputMesh("bunny_solid.obj");
//MeshTransforms.Scale(mesh, 3.0 / mesh.CachedBounds.MaxDim);
//BoundedImplicitFunction3d meshImplicit = meshToImplicitF(mesh, 64, offset);
//generateMeshF(meshImplicit, 128, "c:\\demo\\mesh.obj");
//generateMeshF(new ImplicitOffset3d() { A = meshImplicit, Offset = offset }, 128, "c:\\demo\\mesh_outset.obj");
//generateMeshF(new ImplicitOffset3d() { A = meshImplicit, Offset = -offset }, 128, "c:\\demo\\mesh_inset.obj");
// compare offset of sharp and smooth union
//var smooth_union = new ImplicitSmoothDifference3d() { A = sphere, B = box };
//generateMeshF(smooth_union, 128, "c:\\demo\\smooth_union.obj");
//generateMeshF(new ImplicitOffset3d() { A = smooth_union, Offset = 0.2 }, 128, "c:\\demo\\smooth_union_offset.obj");
//var union = new ImplicitUnion3d() { A = sphere, B = box };
//generateMeshF(new ImplicitOffset3d() { A = union, Offset = offset }, 128, "c:\\demo\\union_offset.obj");
// blending
//ImplicitSphere3d sphere1 = new ImplicitSphere3d() {
// Origin = Vector3d.Zero, Radius = 1.0
//};
//ImplicitSphere3d sphere2 = new ImplicitSphere3d() {
// Origin = 1.5 * Vector3d.AxisX, Radius = 1.0
//};
//generateMeshF(new ImplicitBlend3d() { A = sphere1, B = sphere2, Blend = 1.0 }, 128, "c:\\demo\\blend_1.obj");
//generateMeshF(new ImplicitBlend3d() { A = sphere1, B = sphere2, Blend = 4.0 }, 128, "c:\\demo\\blend_4.obj");
//generateMeshF(new ImplicitBlend3d() { A = sphere1, B = sphere2, Blend = 16.0 }, 128, "c:\\demo\\blend_16.obj");
//generateMeshF(new ImplicitBlend3d() { A = sphere1, B = sphere2, Blend = 64.0 }, 128, "c:\\demo\\blend_64.obj");
//sphere1.Radius = sphere2.Radius = 2.0f;
//sphere2.Origin = 1.5 * sphere1.Radius * Vector3d.AxisX;
//generateMeshF(new ImplicitBlend3d() { A = sphere1, B = sphere2, Blend = 1.0 }, 128, "c:\\demo\\blend_2x_1.obj");
//generateMeshF(new ImplicitBlend3d() { A = sphere1, B = sphere2, Blend = 4.0 }, 128, "c:\\demo\\blend_2x_4.obj");
//generateMeshF(new ImplicitBlend3d() { A = sphere1, B = sphere2, Blend = 16.0 }, 128, "c:\\demo\\blend_2x_16.obj");
//generateMeshF(new ImplicitBlend3d() { A = sphere1, B = sphere2, Blend = 64.0 }, 128, "c:\\demo\\blend_2x_64.obj");
// mesh blending
//DMesh3 mesh1 = TestUtil.LoadTestInputMesh("bunny_solid.obj");
//MeshTransforms.Scale(mesh1, 3.0 / mesh1.CachedBounds.MaxDim);
//DMesh3 mesh2 = new DMesh3(mesh1);
//MeshTransforms.Rotate(mesh2, mesh2.CachedBounds.Center, Quaternionf.AxisAngleD(Vector3f.OneNormalized, 45.0f));
//var meshImplicit1 = meshToImplicitF(mesh1, 64, 0);
//var meshImplicit2 = meshToImplicitF(mesh2, 64, 0);
//generateMeshF(new ImplicitBlend3d() { A = meshImplicit1, B = meshImplicit2, Blend = 0.0 }, 256, "c:\\demo\\blend_mesh_union.obj");
//generateMeshF(new ImplicitBlend3d() { A = meshImplicit1, B = meshImplicit2, Blend = 10.0 }, 256, "c:\\demo\\blend_mesh_bad.obj");
//var meshFullImplicit1 = meshToBlendImplicitF(mesh1, 64);
//var meshFullImplicit2 = meshToBlendImplicitF(mesh2, 64);
//generateMeshF(new ImplicitBlend3d() { A = meshFullImplicit1, B = meshFullImplicit2, Blend = 0.0 }, 256, "c:\\demo\\blend_mesh_union.obj");
//generateMeshF(new ImplicitBlend3d() { A = meshFullImplicit1, B = meshFullImplicit2, Blend = 1.0 }, 256, "c:\\demo\\blend_mesh_1.obj");
//generateMeshF(new ImplicitBlend3d() { A = meshFullImplicit1, B = meshFullImplicit2, Blend = 10.0 }, 256, "c:\\demo\\blend_mesh_10.obj");
//generateMeshF(new ImplicitBlend3d() { A = meshFullImplicit1, B = meshFullImplicit2, Blend = 50.0 }, 256, "c:\\demo\\blend_mesh_100.obj");
//DMesh3 mesh = TestUtil.LoadTestInputMesh("bunny_solid.obj");
//MeshTransforms.Scale(mesh, 3.0 / mesh.CachedBounds.MaxDim);
//MeshTransforms.Translate(mesh, -mesh.CachedBounds.Center);
//Reducer r = new Reducer(mesh);
//r.ReduceToTriangleCount(100);
//double radius = 0.1;
//List<BoundedImplicitFunction3d> Lines = new List<BoundedImplicitFunction3d>();
//foreach (Index4i edge_info in mesh.Edges()) {
// var segment = new Segment3d(mesh.GetVertex(edge_info.a), mesh.GetVertex(edge_info.b));
// Lines.Add(new ImplicitLine3d() { Segment = segment, Radius = radius });
//}
//ImplicitNaryUnion3d unionN = new ImplicitNaryUnion3d() { Children = Lines };
//generateMeshF(unionN, 128, "c:\\demo\\mesh_edges.obj");
//radius = 0.05;
//List<BoundedImplicitFunction3d> Elements = new List<BoundedImplicitFunction3d>();
//foreach (int eid in mesh.EdgeIndices()) {
// var segment = new Segment3d(mesh.GetEdgePoint(eid, 0), mesh.GetEdgePoint(eid, 1));
// Elements.Add(new ImplicitLine3d() { Segment = segment, Radius = radius });
//}
//foreach (Vector3d v in mesh.Vertices())
// Elements.Add(new ImplicitSphere3d() { Origin = v, Radius = 2 * radius });
//generateMeshF(new ImplicitNaryUnion3d() { Children = Elements }, 256, "c:\\demo\\mesh_edges_and_vertices.obj");
//double lattice_radius = 0.05;
//double lattice_spacing = 0.4;
//double shell_thickness = 0.05;
//int mesh_resolution = 64; // set to 256 for image quality
//var shellMeshImplicit = meshToImplicitF(mesh, 128, shell_thickness);
//double max_dim = mesh.CachedBounds.MaxDim;
//AxisAlignedBox3d bounds = new AxisAlignedBox3d(mesh.CachedBounds.Center, max_dim / 2);
//bounds.Expand(2 * lattice_spacing);
//AxisAlignedBox2d element = new AxisAlignedBox2d(lattice_spacing);
//AxisAlignedBox2d bounds_xy = new AxisAlignedBox2d(bounds.Min.xy, bounds.Max.xy);
//AxisAlignedBox2d bounds_xz = new AxisAlignedBox2d(bounds.Min.xz, bounds.Max.xz);
//AxisAlignedBox2d bounds_yz = new AxisAlignedBox2d(bounds.Min.yz, bounds.Max.yz);
//List<BoundedImplicitFunction3d> Tiling = new List<BoundedImplicitFunction3d>();
//foreach (Vector2d uv in TilingUtil.BoundedRegularTiling2(element, bounds_xy, 0)) {
// Segment3d seg = new Segment3d(new Vector3d(uv.x, uv.y, bounds.Min.z), new Vector3d(uv.x, uv.y, bounds.Max.z));
// Tiling.Add(new ImplicitLine3d() { Segment = seg, Radius = lattice_radius });
//}
//foreach (Vector2d uv in TilingUtil.BoundedRegularTiling2(element, bounds_xz, 0)) {
// Segment3d seg = new Segment3d(new Vector3d(uv.x, bounds.Min.y, uv.y), new Vector3d(uv.x, bounds.Max.y, uv.y));
// Tiling.Add(new ImplicitLine3d() { Segment = seg, Radius = lattice_radius });
//}
//foreach (Vector2d uv in TilingUtil.BoundedRegularTiling2(element, bounds_yz, 0)) {
// Segment3d seg = new Segment3d(new Vector3d(bounds.Min.x, uv.x, uv.y), new Vector3d(bounds.Max.x, uv.x, uv.y));
// Tiling.Add(new ImplicitLine3d() { Segment = seg, Radius = lattice_radius });
//}
//ImplicitNaryUnion3d lattice = new ImplicitNaryUnion3d() { Children = Tiling };
//generateMeshF(lattice, 128, "c:\\demo\\lattice.obj");
//ImplicitIntersection3d lattice_clipped = new ImplicitIntersection3d() { A = lattice, B = shellMeshImplicit };
//generateMeshF(lattice_clipped, mesh_resolution, "c:\\demo\\lattice_clipped.obj");
//var shell = new ImplicitDifference3d() {
// A = shellMeshImplicit, B = new ImplicitOffset3d() { A = shellMeshImplicit, Offset = -shell_thickness }
//};
//var shell_cut = new ImplicitDifference3d() {
// A = shell, B = new ImplicitAxisAlignedBox3d() { AABox = new AxisAlignedBox3d(Vector3d.Zero, max_dim / 2, 0.4, max_dim / 2) }
//};
//generateMeshF(new ImplicitUnion3d() { A = lattice_clipped, B = shell_cut }, mesh_resolution, "c:\\demo\\lattice_result.obj");
}
public static void test_marching_cubes_implicits()
{
DMesh3 mesh = TestUtil.LoadTestInputMesh("bunny_solid.obj");
MeshTransforms.Translate(mesh, -mesh.CachedBounds.Center);
double meshCellsize = mesh.CachedBounds.MaxDim / 32;
MeshSignedDistanceGrid levelSet = new MeshSignedDistanceGrid(mesh, meshCellsize);
levelSet.ExactBandWidth = 3;
levelSet.UseParallel = true;
levelSet.ComputeMode = MeshSignedDistanceGrid.ComputeModes.NarrowBandOnly;
levelSet.Compute();
var meshIso = new DenseGridTrilinearImplicit(levelSet.Grid, levelSet.GridOrigin, levelSet.CellSize);
ImplicitOffset3d offsetMeshIso = new ImplicitOffset3d()
{
A = meshIso, Offset = 2.0
};
double r = 15.0;
ImplicitSphere3d sphere1 = new ImplicitSphere3d()
{
Origin = Vector3d.Zero,
Radius = r
};
ImplicitSphere3d sphere2 = new ImplicitSphere3d()
{
Origin = r * Vector3d.AxisX,
Radius = r
};
ImplicitAxisAlignedBox3d aabox1 = new ImplicitAxisAlignedBox3d()
{
AABox = new AxisAlignedBox3d(r * 0.5 * Vector3d.One, r, r * 0.75, r * 0.5)
};
ImplicitBox3d box1 = new ImplicitBox3d()
{
Box = new Box3d(new Frame3f(r * 0.5 * Vector3d.One, Vector3d.One.Normalized),
new Vector3d(r, r * 0.75, r * 0.5))
};
ImplicitLine3d line1 = new ImplicitLine3d()
{
Segment = new Segment3d(Vector3d.Zero, r * Vector3d.One),
Radius = 3.0
};
ImplicitHalfSpace3d half1 = new ImplicitHalfSpace3d()
{
Origin = Vector3d.Zero, Normal = Vector3d.One.Normalized
};
ImplicitUnion3d union = new ImplicitUnion3d()
{
A = sphere1, B = line1
};
ImplicitDifference3d difference = new ImplicitDifference3d()
{
A = meshIso, B = aabox1
};
ImplicitIntersection3d intersect = new ImplicitIntersection3d()
{
A = meshIso, B = half1
};
ImplicitNaryUnion3d nunion = new ImplicitNaryUnion3d()
{
Children = new List <BoundedImplicitFunction3d>()
{
offsetMeshIso, sphere1, sphere2
}
};
ImplicitNaryDifference3d ndifference = new ImplicitNaryDifference3d()
{
A = offsetMeshIso,
BSet = new List <BoundedImplicitFunction3d>()
{
sphere1, sphere2
}
};
ImplicitBlend3d blend = new ImplicitBlend3d()
{
A = sphere1, B = sphere2
};
BoundedImplicitFunction3d root = intersect;
AxisAlignedBox3d bounds = root.Bounds();
int numcells = 64;
MarchingCubes c = new MarchingCubes();
c.RootMode = MarchingCubes.RootfindingModes.LerpSteps;
c.RootModeSteps = 5;
c.Implicit = root;
c.Bounds = bounds;
c.CubeSize = bounds.MaxDim / numcells;
c.Bounds.Expand(3 * c.CubeSize);
c.Generate();
MeshNormals.QuickCompute(c.Mesh);
TestUtil.WriteTestOutputMesh(c.Mesh, "marching_cubes_implicit.obj");
}
