8.64. Create Surface Mesh (Surface Nets)

Group (Subgroup)

Surface Meshing (Generation)

Description

This filter uses the algorithm from {1} to produce a triangle surface mesh. The code is directly based on the sample code from the paper but has been modified to work with the simplnx library classes. This filter uses a different algorithm that aims to produce a mush that keeps sharp edges while still producing a mesh superior to marching cubes or QuickMesh.

From the abstract of the paper:

    We extend 3D SurfaceNets to generate surfaces of segmented 3D medical images composed
    of multiple materials represented as indexed labels. Our extension generates smooth, high-
    quality triangle meshes suitable for rendering and tetrahedralization, preserves topology and
    sharp boundaries between materials, guarantees a user-specified accuracy, and is fast enough
    that users can interactively explore the trade-off between accuracy and surface smoothness.

This filter will ensure that the smallest of the 2 FaceLabel values will always be in the first component (component[0]). This will allow assumptions made in downstream filters to continue to work correctly.

Example SurfaceNets Output

SurfaceNets without the built-in smoothing applied

Example SurfaceNets Output

SurfaceNets output with the built-in smoothing operation applied.

Node Types

During the meshing process, each vertex, or node, will get a “Node Type” value assigned to it. These will range from 0 to 6. The value is an internal representation from the SurfaceNets algorithm. They are roughly equivelent to the Node Types from the Quick Surface Mesh algorithm but not strictly the same.

Node Type = 0: This is a node that ONLY has 2 features connected to the node.
Node Type = 2: This is a node that has 3 features connected to the node, such as a triple line
Node Type = 3-6: These nodes have 4 or more features connected to the node.

Node Type	Example Image
0
2
3
4
6

Exterior or Boundary Nodes

Nodes that appear on the exterior of a volume have Node Type values starting at 10 and going up from there. For instance, a triple line that is also on the exterior of the volume should have a value of 12.

Exterior Node Types

Exterior or Boundary Triangles

Each triangle that is created will have an 2 component attribute called Face Labels that represent the Feature ID on either side of the triangle. If one of the triangles represents the border of the virtual box then one of the FaceLables will have a value of -1.

Notes

This filter should be used in place of the “QuickMesh Surface Filter”.

Input Parameter(s)

Parameter Name	Parameter Type	Parameter Notes	Description
Apply smoothing operations	Bool		Use the built in smoothing operation.
Relaxation Iterations	Scalar Value	Int32	Number of relaxation iterations to perform. More iterations causes more smoothing.
Max Distance from Voxel Center	Scalar Value	Float32	The maximum allowable distance that a node can move from the voxel center
Relaxation Factor	Scalar Value	Float32	The factor used to determine how far a node can move in each smoothing iteration

Input Cell Data

Parameter Name	Parameter Type	Parameter Notes	Description
Input Image Geometry	Geometry Selection	Image	DataPath to input Image Geometry
Cell Feature Ids	Array Selection	Allowed Types: int32 Comp. Shape: 1	The complete path to the Array specifying which Feature each Cell belongs to

Output Triangle Geometry

Parameter Name	Parameter Type	Parameter Notes	Description
Created Triangle Geometry	DataGroupCreation		The name of the created Triangle Geometry

Output Vertex Data

Parameter Name	Parameter Type	Parameter Notes	Description
Vertex Data [AttributeMatrix]	DataObjectName		The complete path to the DataGroup where the Vertex Data of the Triangle Geometry will be created
Node Type	DataObjectName		The complete path to the Array specifying the type of node in the Triangle Geometry

Output Face Data

Parameter Name	Parameter Type	Parameter Notes	Description
Face Data [AttributeMatrix]	DataObjectName		The complete path to the DataGroup where the Face Data of the Triangle Geometry will be created
Face Labels	DataObjectName		The complete path to the Array specifying which Features are on either side of each Face in the Triangle Geometry

Output Feature Data

Parameter Name	Parameter Type	Parameter Notes	Description
Face Feature Data [AttributeMatrix]	DataObjectName		The complete path to the DataGroup where the Feature Data will be stored.

Example Pipelines

    Pipelines/SimplnxCore/SurfaceNets_Demo.d3dpipeline

Citations

{1}SurfaceNets for Multi-Label Segmentations with Preservation of Sharp Boundaries

License & Copyright

Sarah F. Frisken, SurfaceNets for Multi-Label Segmentations with Preservation of Sharp Boundaries, Journal of Computer Graphics Techniques (JCGT), vol. 11, no. 1, 34–54, 2022 http://jcgt.org/published/0011/01/03

DREAM3D-NX Mailing Lists

If you need more help with a Filter, please consider asking your question on the DREAM3D-NX Users Google group!