mutable struct SimplexGridBuilder

Simplex grid builder: wrapper around array based mesh generator interface. It allows to build up the input data incrementally.

SimplexGridBuilder(; Generator=nothing,
                     tol=1.0e-12,
                     checkexisting=true)

Create a SimplexGridBuilder.

• Generator: module corresponding to mesh generator package. Valid choices are TetGen and Triangulate, corresponding to the respective Julia packages.
• checkexisting: whether to check for already existing points
• tol: two points below this tolerance will be merged if checkexisting is true

dim_space(builder)

Space dimension of builder.

simplexgrid(builder; kwargs...)

Build simplex grid from the current state of the builder. kwargs overwrite those set with the options! method. See default_options for available kwargs.

cellregion!(builder,region)

Set the current cell region (acts on subsequent regionpoint() calls)

Cell regions can be used to distinguish cells of different materials etc. In the API they are characterized by

• region number set via cellregion!
• maximum cell volume set via maxvolume!
• region point set via regionpoint!. This is some point located within the respective region which must be surrounded by facets in a watertight manner.

checkexisting!(builder, b)

Whether to check for already existing points

facet!(builder,i1)
facet!(builder,i1,i2)
facet!(builder,i1,i2,i3,i4)
facet!(builder,vector_or_tuple)
facet!(builder, (x1,y1), (x2,y2))
facet!(builder, (x1,y1,z1), (x2,y2,z2),(x3,y3,z3))

Add a facet via the corresponding point indices returned by point!.

Facets of two points are solely used for 2D grids. Facets with more than two points are used for 3D grids and must be planar.

facetregion!(builder,region)

Set the current facet region. Subsequent facets will be marked with this number. Facet regions can be used to mark different parts of the boundary, e.g. for distinguishing boundary conditions.

flags(builder)

Return mesh generator specific flag string created from builder options.

holepoint!(builder,x)
holepoint!(builder,x,y)
holepoint!(builder,x,y,z)
holepoint!(builder,vec_or_tuple)

Add a point marking a hole region. Hole regions need to be surrounded by facets in a watertight manner.

maxvolume!(builder,vol)

Set the current cell volume resp. area (acts on subsequent regionpoint() calls). See cellregion!.

 maybewatertight(this::SimplexGridBuilder; bregions=nothing)

Check if facets belonging to boundare regions in bregions are watertight. This is based on a number of heuristics, only a negative answer is definitive.

options!(builder; kwargs...)

Set some mesh generation options, see default_options

point!(builder,x)
point!(builder,x,y)
point!(builder,x,y,z)
point!(builder,vec_or_tuple)

Add point or merge with already existing point. Returns its index which can be used to set up facets with facet!.

polyfacet!(builder,vector_or_tuple)

Add a polygonal facet via the corresponding point indices returned by point!.

Facets with more than two points are used for 3D grids and must be planar.

regionpoint!(builder,x)
regionpoint!(builder,x,y)
regionpoint!(builder,x,y,z)
regionpoint!(builder,vec_or_tuple)

Add a region point marking a region, using current cell volume an cell region See cellregion!.

default_options()

Create dictionary of mesh generation options with default values. These at once describe the keyword arguments available to the methods of the package and are listed in the following table:

For mesh generation, these are turned into mesh generator control flags. This process can be completely overwritten by specifying the flags parameter.

For the flags parameter in 2D see the short resp. long documentation of the Triangle control flags.

For the 3D case, see the corresponding TetGen flags

The unsuitable parameter should be a function, see triunsuitable! .

builderplot(gb::SimplexGridBuilder; Plotter, kwargs...)

Two panel visualization of gridfactory with input and resulting grid See default_options for available kwargs.

bregions!(builder::SimplexGridBuilder,grid,regionlist;facetregions=nothing)

Add all boundary facets of grid with region numbers in region list to geometry description. The optional parameter facetregions allows to overwrite the numbers in regionlist.

bregions!(builder::SimplexGridBuilder,grid, pairs...)

Add boundary facets of grid with region numbers mentioned as first element in pairs with region number mentioned as second element of pairs to the geometry description. If no pairs are given, add all boundary facets of grid with their original region numbers to builder.

Example:

bregions!(builder,grid, 1=>2, 3=>5)

circle!(builder, center, radius; n=20)

Add points and facets approximating a circle.

lineto!(builder, pt)

Generate a line from the current pen position to the target point pt, s moveto!(), (2D, 3D). pt is either an existing point index or a table of point coordinates. In the latter case, the point is added. It returns index of the target point.

Example 2D: draw a square with different facetregion numbers

 p = moveto!(b,[0,0])
 facetregion!(b,1);  lineto!(b,[1,0])
 facetregion!(b,2);  lineto!(b,[1,1])
 facetregion!(b,3);  lineto!(b,[0,1])
 facetregion!(b,4);  lineto!(b,p)

Example 3D: two planar facet with different facetregion numbers

 facetregion!(b,1);
 p1 = moveto!(b,[0,0,0])
 p2 = moveto!(b,[1,0,0])
 p3 = moveto!(b,[1,1,0])
 p4 = moveto!(b,[0,1,0])
 polyfacet!(b,[p1,p2,p3,p4])

 facetregion!(b,2);
 p1 = moveto!(b,[0,0,1])
 p2 = moveto!(b,[1,0,1])
 p3 = moveto!(b,[1,1,1])
 p4 = moveto!(b,[0,1,1])
 polyfacet!(b,[p1,p2,p3,p4])

  mesh3d!(builder, mesh; translate=(0,0,0), cellregion=0, hole=false)

Incorporate 3d model from mesh.

model3d!(builder, filename; translate=(0,0,0), cellregion=0, hole=false)

Load 3D model from file. File formats are those supported by MeshIO.jl.

moveto!(builder, pt)

Move the (virtual) pen to the target point pt (2D, 3D). pt is either an existing point index or a table of point coordinates. In the latter case, the point is added. It returns index of the target point.

rect2d!(builder, sw, ne; facetregions=nothing)

Add points and facets describing a rectangle via points describing its south-west and north-east corners. On default, the corresponding facet regions are deduced from the current facetregion. Alternatively, a 4-vector of facetregions can be passed.

rect3d!(builder, bsw, tne; facetregions=nothing)

Add points and facets describing a qudrilateral via points describing its bottom south-west and top north-east corners. On default, the corresponding facet regions are deduced from the current facetregion. Alternatively, a 6-vector of facetregions can be passed (in the sequence s-e-n-w-b-t)

sphere!(builder, center, radius; nref=3)

Add points and facets approximating a sphere. nref is a refinement level.