1. LaGriT Los Alamos Grid Toolbox Carl Gable meshing.lanl.gov lagrit.lanl.gov

2. LaGriT Mesh Generation Mesh Optimization Geometric Computing Element and Node Set Manipulation IO, Boundary Conditions, Initial Conditions

3. LaGriT: Mesh Generation Delaunay point connection –2D triangulation –3D tetrahedralization

4. LaGriT: Mesh Generation 2D arbitrary (concave) polygon triangulation

5. LaGriT: Mesh Generation Block structured i,j,k connectivity 2.5D Stacking of z(x,y) surfaces 2x5 3x2

6. LaGriT Mesh Optimization Refine –edge, face, element –Rivara Refine –field value, field gradient, aspect ratio, volume, arbitrary point

7. LaGriT Mesh Optimization Derefine –edge length, volume, aspect Original Elements Filter: Remove small area and high aspect ratio elements while maintaining geometry.

8. LaGriT Mesh Optimization Smooth –elliptic, laplace, random Massage - refine-derefine-smooth

9. LaGriT Geometry Constructive Solid Geometry surface/s_a/intrface/cylinder/x1,y1,z1/x2,y2,z2/radius surface/s_b/intrface/cylinder/x1,y1,z1/x2,y2,z2/radius surface/s_c/intrface/box/xmin,ymin,zmin/xmax,ymax,zmax/ region/r_ring/gt s_c and gt s_b and le s_a

10. Element Element Intersection Mesh-Mesh Element Intersection –Determine elements of mesh_a that are intersected by mesh_b mesh_a mesh_b

11. LaGriT Geometric Computing pointlinetriquadtetpyrhex point XXXXXXX line XXXXXX tri XXXXXX quad XXXXXX tet XXXXXX pyr X hex XXXXXX Mesh-Mesh Element Intersection –Compute intersection of mesh_a with mesh_b Mesh-Mesh Intersection –Compute the line of intersection between two triangulated surfaces in 3D space

12. Example: Mesh-2-Mesh Intersect Intersect fault surfaces with mesh to select elements to be refined with quadtree type refine.

13. LaGriT Element and Node Set Manipulation Point and Element Sets: PSET, ELTSET –Attribute: le,lt,ge,gt,eq,ne e.g. nodes/elements with saturation > 0.5 –Geometry: xyz, rtz, rtp e.g. nodes/elements inside a box, cylinder, sphere –Region e.g. identify all nodes/elements inside a region –Logical: union, intersect, not e.g. nodes/elements inside a sphere and saturation > 0.5 e.g. nodes/elements inside a sphere or saturation > 0.5

14. LaGriT Element and Node Manipulation Commands Translate Scale Rotate: rotatept, rotateln Filter Perturb Remove Multi-Key Sort Reorder KDTree Search

15. LaGriT Grid Attributes Real and integer node and element attributes Element area, element volume aspect ratio, dihedral angle, solid angle, min/max edge length ratio Identify Sliver, Wedge, Needle, Cap Unit normal, area normal vector Synthetic normal to surface nodes Volume/Area integration of floating point node or cell attributes Dual mesh connectivity Voronoi and median volume and face area

16. LaGriT Output Options PyLith GeoFEST FEHM AVS, GMV, Tecplot STL, FLAG, X3D

17. Mesh Manipulation Extract Lower D - 3D – 2D – 1D –Volume, Face, Line Extract 2D Surface (plane, isosurface, arbitrary triangulation) from 3D mesh Extract Line (well bore) from 3D mesh

18. Mesh Manipulation Extract 2D Surface (plane) from 3D mesh.

19. Example: Mesh-2-Mesh Interpolate Source mesh with attribute defined on nodes. Sink mesh with attributes interpolated from source mesh. Nodes in sink mesh outside source mesh are identified. 0,0

20. Example Mesh-2-Mesh Interpolation Voronoi – Nearest Point Integer Interpolation Colors of fine quad mesh indicate nearest node of low resolution points.

21. Same Geometry, Different Mesh Method

22. METIS Interface Supports METIS mesh partition algorithm calls Partition: metis /partition/ metis_partmeshnodal / node / 32 metis /partition/ metis_partmeshdual / dual / 32 Reorder: metis / reorder / metis_edgend / dual metis / reorder / metis_nodend / node

23. What is the LaGriT Interface? Command Line Driven Control File Driven Call from Fortran, C, C++ Data structures can be accessed and manipulated by user Developer interface for extension and user modules Platforms: Linux, Mac, Sun, SGI

24. What LaGriT Is Not No GUI interface No advancing front algorithm No interface for ACIS, Autocad, … CAD Not unstructured hex mesh (see Cubit)

25. Southern California Earthquake Center (SCEC) Community Fault Model (CFM) Landers Hector Mine ~54km EW ~60km NS ~17km Z

26. Finite Element Mesh With CFM Landers & Hector Mine Faults Tet Aspect Ratio Tetrahedral Finite Element MeshTetrahedral Finite Element Mesh 340km EW, 360km NS, 124km Z340km EW, 360km NS, 124km Z Element size ~50km far fieldElement size ~50km far field Element size ~500m near faultsElement size ~500m near faults

27. Mojave Block Model Original Block Triangles Filtered Block Triangles: Remove small area and high aspect ratio elements while maintaining geometry.

28. LaGriT meshing.lanl.gov lagrit.lanl.gov