Parametrization

The Parametrization tab provides tools for fitting and working with models.

Sphere

#sphere

Ellipse

#ellipsoid

Cylinder

#cylinder

RBF

#rbf

Mesh

#mesh

Curve

#curve

Sample

#sample

Repair

#repair

Remesh

#remesh

Smooth

#smooth

Project

#project

Parametric Fitting

Fit basic geometric shapes to point clouds:

Sphere

Fits a sphere using least squares optimization:

1. Select a cluster with spherical shape

2. Click Sphere to fit the model

3. The fitted sphere appears in the Models section

Ellipsoid

Fits an ellipsoid using eigenvalue decomposition and least squares optimization:

1. Select a cluster with ellipsoidal shape

2. Click Ellipsoid to fit the model

3. The fitted ellipsoid appears in the Models section

Cylinder

Fits a cylinder using PCA and iterative refinement:

1. Select a cluster with cylindrical or tubular shape

2. Click Cylinder to fit the model

3. The fitted cylinder appears in the Models section

Non-Parametric Fitting

RBF (Radial Basis Function)

Creates smooth, non-parametric surface models through radial basis function interpolation. Ideal for complex, non-parametric shapes that can be represented as height fields, i.e. an open membrane section.

1. Select a cluster with surface-like structure

2. Click RBF

3. Configure interpolation direction:

   • xy: Surface as function of x,y coordinates

   • xz: Surface as function of x,z coordinates

   • yz: Surface as function of y,z coordinates

4. Click OK to create the interpolated surface

Mesh

1. Select a cluster with sufficient point density

2. Click Mesh

3. Choose reconstruction method:

   • Alpha Shape: Convex hull with alpha parameter control

   • Ball Pivoting: Robust surface reconstruction for structured data

   • Cluster Ball Pivoting: Ball pivoting with automatic parameter determination

   • Poisson: Watertight surface reconstruction

   • Marching Cubes: Meshing of dense segmentations

   • Flying Edges: Like marching cubes but faster

4. Configure method-specific parameters:

   Alpha Shape Parameters:

   • Alpha: Controls shape complexity (higher = coarser features)

   • Scaling Factor: Mesh resampling resolution

   • Distance: Threshold for inferred vs. measured vertices

   Ball Pivoting Parameters:

   • Radii: Ball radii for reconstruction (comma-separated, e.g., “5,3.5,1.0”)

   • Downsample: Thin input point cloud to core points

   • Smoothing Steps: Pre-smoothing iterations

   Poisson Parameters:

   • Depth: Octree depth (higher = more detail)

   • Samples: Minimum points per octree node

   • Pointweight: Interpolation weight of input points

5. Set repair parameters:

   • Elastic Weight: Controls mesh elasticity (0 = strong anchoring)

   • Curvature Weight: Controls curvature propagation

   • Volume Weight: Controls internal mesh pressure

   • Hole Size: Maximum hole area for automatic filling

6. Click OK to generate the mesh

Note: Mesh quality depends on point cloud density and noise levels. For noisy data, increase smoothing steps. For sparse data, reduce the number of neighbors.

Curve

Fits spline curves of requested order to sequential control point data. Good for creating smooth curves from hand-drawn paths:

1. Create control points using drawing mode:

   • Press Shift+A to enter curve drawing mode

   • Click to place control points in sequence

   • Press Enter to complete the curve

   • OR select an existing cluster with linear structure

2. Click Curve

3. Configure spline parameters: - Order: Spline degree (1=linear, 3=cubic, 5=quintic)

4. Click OK to fit the curve

Sampling Operations

Sample

Creates point clouds from fitted models:

1. Select one or more models in the Object Browser

2. Click Sample

3. Configure sampling parameters:

   Sampling Method:

   • Points: Generate specified number of points

   • Distance: Generate points with specified average spacing

   Parameters:

   • Sampling: Number of points or point spacing value

   • Offset: Normal-direction offset from surface (useful for particle picking)

4. Click OK to generate sample points

Mesh Operations

Repair

Fixes mesh topology issues and fills holes using Leipa triangulation and fairing:

1. Select mesh models to repair

2. Click Repair

3. Configure repair parameters:

   Optimization Weights:

   • Elastic Weight: Mesh smoothness (0=anchor to original, 1=free movement)

   • Curvature Weight: Preserve or modify curvature

   • Volume Weight: Internal pressure (positive=inflation, negative=shrinkage)

   • Boundary Ring: Optimize n-ring vertices around boundaries

   Hole Filling:

   • Hole Size: Maximum hole area to fill (-1=fill all holes)

4. Click OK to repair meshes

Remesh

Improves mesh quality and adjusts triangle density:

1. Select mesh models to remesh

2. Click Remesh

3. Choose remeshing method:

   Edge Length:

   • Edge Length: Target average edge length

   • Iterations: Number of optimization passes

   • Mesh Angle: Preserve edges above this angle threshold

   Vertex Clustering:

   • Radius: Clustering radius for vertex merging

   Quadratic Decimation:

   • Triangles: Target triangle count

   Subdivide:

   • Iterations: Number of subdivision passes

   • Smooth: Use smooth Loop subdivision vs. simple midpoint

4. Configure method-specific parameters

5. Click OK to remesh

Use Cases:

• Edge Length: Create uniform triangle sizes for simulation

• Vertex Clustering: Quick mesh simplification

• Quadratic Decimation: High-quality mesh reduction

• Subdivide: Increase resolution for detailed modeling

Smooth

Improves mesh quality by smoothing surface.

1. Select mesh models to smooth

2. Click Smooth

3. Choose remeshing method:

   Taubin:

   • Solid smoothing without net shrinkage

   Laplacian:

   • Very smooth mesh but net shrinkage

   Average:

   • Mesh denoising but net shrinkage

   Parameters:

   • Iterations: Number of smoothing iterations (higher is smoother)

4. Click OK to remesh

Project

Projects point clouds onto mesh surfaces using ray casting:

1. Select exactly one mesh model (target surface)

2. Select one or more point cloud clusters (sources to project)

3. Click Project

4. Configure projection settings:

   Projection Method:

   • Cast Normals: Use point normal vectors for ray casting

   • Invert Normals: Reverse normal direction

5. Click OK to perform projection

Results:

• Creates new point clouds with projected coordinates

• Generates updated mesh with projection points integrated

• Preserves original data while adding projected versions

Next Steps

Continue to the Intelligence tab to learn about advanced features like HMFF and membrane segmentation.