Prismatic mesh (prismatic_mesh)¶
Work in progress
This component is under development. Its options may change, and it has no tutorial yet.
Work in progress. From a topological_offset construction (a .vtu, or a .msh with corr_input_vid), thins the offset band around the solid to a target thickness and, with prism_dominant, rebuilds it as prisms, pyramids and tets.
Spec source · Defaults · JSON Schema
Required¶
application¶
string · required · one of prismatic_mesh
Application name must be prismatic_mesh.
input¶
string · required
Construction .vtu or Gmsh 4.1 .msh with corr_input_vid. MSH can derive labels and cell tags from the tag_0/offset/ambient physical groups; explicit PRISM fields are also supported.
output¶
string · required
Output .vtu or .msh (Gmsh 4.1 ASCII) filename, relative to the JSON directory. A missing extension becomes .vtu.
Key options¶
thicknessratio¶
float · default 0.1
Positive target thickness relative to the mean length of unique input surface edges.
iterations¶
int · default 5
Number of collapse/smoothing iterations; 0 computes targets without optimization.
prism_dominant¶
bool · default false
After optimization, reconstruct conforming prisms, input-apex shell pyramids and tetrahedra. Retained background receives kernel-point pyramids in feasible disjoint quad-diagonal edge-star cavities. Preserve existing points, input volume and non-cavity background; fall back to conforming tet regions on failed geometry, overlap or search limits.
keep_background_mesh¶
bool · default false
Keep exterior background tetrahedra during optimization/output. Background must remain strictly positive. Without background_remeshing only offset vertices move. Targets are computed from the band alone.
Other options¶
export_input_and_shell¶
bool · default false
Additionally export the union of input volume and offset band as <output_stem>_input_shell.msh and .vtu, using the same final coordinates, hybrid cells and attributes while omitting background cells.
min_tet_volume¶
float · default 0
Optional nonnegative signed-volume floor for new or modified shell tetrahedra, candidate pyramid decompositions and new background pyramid cavity cones. The default zero requires strictly positive volume using exact predicates, without a coordinate-scale-dependent cutoff. Background optimization and unchanged background tets also require strictly positive volume.
smoothing_max_backtracks¶
int · default 40
Maximum smoothing step halvings after the full target step; between 0 and 60.
jacobian_smoothing_iterations¶
int · default 0
Optional prism Jacobian smoothing rounds after tet optimization. Zero disables this stage. Only offset vertices move; input, correspondence and connectivity remain fixed.
jacobian_target¶
float · default 0.01
Positive target det(J), normalized by twice input triangle area times initial mean column length.
jacobian_position_weight¶
float · default 0.001
Positive quadratic weight on displacement from the position before Jacobian smoothing, normalized by target thickness (initial column length if unavailable).
jacobian_max_step_ratio¶
float · default 0.25
Positive per-move displacement bound relative to thickness. Implemented with an inscribed axis-aligned box.
jacobian_max_displacement_ratio¶
float · default 0.5
Positive total displacement bound from the position before Jacobian smoothing, relative to thickness. Implemented with an inscribed axis-aligned box.
background_remeshing¶
bool · default false
Enable adaptive background 2-3/3-2 swaps and interior relaxation after each tet iteration, then retry collapse. Requires keep_background_mesh=true. Input/offset vertices and exterior boundary are fixed during remeshing.
background_remeshing_passes¶
int · default 2
Local remeshing passes per tet iteration; positive.
background_quality_threshold¶
float · default 0.1
Trigger on background mean ratio below this threshold in (0,1]; 1 is a regular tet, 0 is degenerate. Background-blocked collapses are also repair targets.
background_remeshing_max_operations¶
int · default 500
Maximum accepted background swaps/moves per tet iteration; positive.
background_remeshing_max_attempts¶
int · default 20000
Maximum attempted background swaps/moves per tet iteration; positive.
Run control¶
input_dir¶
string · default ""
Base directory for input; set by wmtk_app to the JSON directory.