4.2.6. Options for Mesh Section

The options below are the available options in the Mesh Section of the pycart.json control file

MeshFile: {None} | str

original mesh file name(s)

XLev: {None} | XLevOpts

list of XLev specs for add’l surface refinements

An XLev specification tells cubes to perform a number of additional refinements on any cut cells that intersect a triangle from a named (or numbered) component. This refinement can violate the maxR command-line input to cubes and is very useful for ensuring that small features of the surface have adequate resolution in the initial volume mesh.

The following example specifies two additional refinements (after the initial run-through by cubes) on all triangles in the component "fins". These instructions are then written to preSpec.c3d.cntl.

{
    "compID": "fins",
    "n": 2
}

inputC3d: {'input.c3d'} | str

file name of pre-generated input.c3d

mesh2d: {False} | bool | bool_

option to build 2D mesh

TriFile: {None} | str

original surface triangulation file(s)

BBox: {None} | BBoxOpts

list of bounding boxes for volume mesh creation

This defines bounding boxes using the name of a component taken from a Cart3D Config.xml file. The cape.tri.Tri class automatically finds the smallest bounding box that contains this component, and then the user can specify additional margins beyond this box (margins can also be negative). Separate margins (or “pads”) on theminimum and maximum coordinates can be given following the convention "xm" (short for x-minus) on the minimum coordinate and "xp" for the maximum coordinate.

{
    "compID": "fin2",
    "n": 9,
    "pad": 2.0,
    "xpad": 3.0,
    "ym": -1.0,
    "yp": 3.0
}