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");
}
public virtual void Generate()
{
AxisAlignedBox3d graphBox = Graph.CachedBounds;
graphBox.Expand(2 * PostRadius);
double cellSize = (SamplerCellSizeHint == 0) ? (PostRadius / 5) : SamplerCellSizeHint;
ImplicitFieldSampler3d sampler = new ImplicitFieldSampler3d(graphBox, cellSize);
ActualCellSize = cellSize;
// sample segments into graph
ImplicitLine3d line = new ImplicitLine3d()
{
Radius = PostRadius
};
foreach (int eid in Graph.EdgeIndices())
{
Index2i ev = Graph.GetEdgeV(eid);
Vector3d v0 = Graph.GetVertex(ev.a);
Vector3d v1 = Graph.GetVertex(ev.b);
double r = PostRadius;
int upper_vid = (v0.y > v1.y) ? ev.a : ev.b;
if (TipVertices.Contains(upper_vid))
{
r = TipRadius;
}
line.Segment = new Segment3d(v0, v1);
line.Radius = r;
sampler.Sample(line, line.Radius / 2);
}
foreach (int vid in GroundVertices)
{
Vector3d v = Graph.GetVertex(vid);
sampler.Sample(new ImplicitSphere3d()
{
Origin = v - (PostRadius / 2) * Vector3d.AxisY, Radius = GroundRadius
});
}
ImplicitHalfSpace3d cutPlane = new ImplicitHalfSpace3d()
{
Origin = Vector3d.Zero, Normal = Vector3d.AxisY
};
ImplicitDifference3d cut = new ImplicitDifference3d()
{
A = sampler.ToImplicit(), B = cutPlane
};
MarchingCubes mc = new MarchingCubes()
{
Implicit = cut, Bounds = graphBox, CubeSize = PostRadius / 3
};
mc.Bounds.Min.y = -2 * mc.CubeSize;
mc.Bounds.Min.x -= 2 * mc.CubeSize; mc.Bounds.Min.z -= 2 * mc.CubeSize;
mc.Bounds.Max.x += 2 * mc.CubeSize; mc.Bounds.Max.z += 2 * mc.CubeSize;
mc.CancelF = this.Cancelled;
mc.Generate();
ResultMesh = mc.Mesh;
}
