Sculpt Bounding Box/Mesh Size

Sculpt options for setting up the Cartesian base grid and the initial cell sizes. An overlay Cartesian grid is used as the basis for the all-hex mesh that will be produced. The bounds and size of the cells specified for the grid will dictate the characteristics and resolution of the FEA mesh. The grid can be defined in one of two ways:

  1. Define the bounding box and number of intervals in each coordinate direction. (xmin, ymin, zmin, xmax, ymax, zmax, nelx, nely, nelz)
  2. Define a cell_size. Sculpt will then automatically define the Cartesian grid coordinates and intervals by evaluating the bounding box of the input geometry and adding a small number of cells in each coordinate direction.

Other options for setting up the grid include "align" and "expand" which are normally used with the second method. The align option will automatically rotate the grid to best match the characteristic direction of the geometry rather than maintaining alignment with the global Cartesian directions. The expand option over-rides the default expansion of the Cartesian grid beyond the bounding box of the geometry and allow the user to specify a specific expansion percentage. 


Bounding Box/Mesh Size 	--bbox 	-box
  --nelx                 -x   <arg> Num cells in X in overlay Cartesian grid       
  --nely                 -y   <arg> Num cells in Y in overlay Cartesian grid       
  --nelz                 -z   <arg> Num cells in Z in overlay Cartesian grid       
  --xmin                 -t   <arg> Min X coord of overlay Cartesian grid          
  --ymin                 -u   <arg> Min Y coord of overlay Cartesian grid          
  --zmin                 -v   <arg> Min Z coord of overlay Cartesian grid          
  --xmax                 -q   <arg> Max X coord of overlay Cartesian grid          
  --ymax                 -r   <arg> Max Y coord of overlay Cartesian grid          
  --zmax                 -s   <arg> Max Z coord of overlay Cartesian grid          
  --cell_size            -cs  <arg> Cell size (nelx, nely, nelz ignored)           
  --align                -a         Automatically align geometry to grid           
  --bbox_expand          -be  <arg> Expand tight bbox by percent                   

Sculpt Command Summary

Number of Intervals

Command: nelx     Num cells in X in overlay Cartesian grid

Input file command:   nelx <arg>
Command line options: -x <arg>
Argument Type:        integer > 0
Command Description:

Defines the number of intervals in the x direction of the base Cartesian grid used for defining the volume fraction definition and meshing For best results the intervals specified should result in approximately equilateral cells.

See also nely, nelz

Number of Intervals

Command: nely     Num cells in Y in overlay Cartesian grid

Input file command:   nely <arg>
Command line options: -y <arg>
Argument Type:        integer > 0
Command Description:

Defines the number of intervals in the y direction of the base Cartesian grid used for defining the volume fraction definition and meshing For best results the intervals specified should result in approximately equilateral cells.

See also nelx, nelz

Number of Intervals

Command: nelz     Num cells in Z in overlay Cartesian grid

Input file command:   nelz <arg>
Command line options: -z <arg>
Argument Type:        integer > 0
Command Description:

Defines the number of intervals in the z direction of the base Cartesian grid used for defining the volume fraction definition and meshing For best results the intervals specified should result in approximately equilateral cells.

See also nelx, nely

Bounding Box Range

Command: xmin     Min X coord of overlay Cartesian grid

Input file command:   xmin <arg>
Command line options: -t <arg>
Argument Type:        floating point value
Command Description:

Defines the minimum x coordinate of the bounding box or range of the Cartesian mesh to be used for meshing.

See also ymin, zmin, xmax, ymax, zmax.

Bounding Box Range

Command: ymin     Min Y coord of overlay Cartesian grid

Input file command:   ymin <arg>
Command line options: -u <arg>
Argument Type:        floating point value
Command Description:

Defines the minimum y coordinate of the bounding box or range of the Cartesian mesh to be used for meshing.

See also xmin, zmin, xmax, ymax, zmax.

Bounding Box Range

Command: zmin     Min Z coord of overlay Cartesian grid

Input file command:   zmin <arg>
Command line options: -v <arg>
Argument Type:        floating point value
Command Description:

Defines the minimum z coordinate of the bounding box or range of the Cartesian mesh to be used for meshing.

See also xmin, ymin, xmax, ymax, zmax.

Bounding Box Range

Command: xmax     Max X coord of overlay Cartesian grid

Input file command:   xmax <arg>
Command line options: -q <arg>
Argument Type:        floating point value
Command Description:

Defines the maximum x coordinate of the bounding box or range of the Cartesian mesh to be used for meshing.

See also xmin, ymin, zmin, ymax, zmax.

Bounding Box Range

Command: ymax     Max Y coord of overlay Cartesian grid

Input file command:   ymax <arg>
Command line options: -r <arg>
Argument Type:        floating point value
Command Description:

Defines the maximum y coordinate of the bounding box or range of the Cartesian mesh to be used for meshing.

See also xmin, ymin, zmin, xmax, zmax.

Bounding Box Range

Command: zmax     Max Z coord of overlay Cartesian grid

Input file command:   zmax <arg>
Command line options: -s <arg>
Argument Type:        floating point value
Command Description:

Defines the maximum z coordinate of the bounding box or range of the Cartesian mesh to be used for meshing.

See also xmin, ymin, zmin, xmax, ymax.

Cell Size

Command: cell_size     Cell size (nelx, nely, nelz ignored)

Input file command:   cell_size <arg>
Command line options: -cs <arg>
Argument Type:        floating point value
Command Description:

Defines a target edge size for the cells of the base Cartesian grid. Both interval and cell_size can not be specified simultaneously. If cell_size is used without a range specification, a bounding box of the geometry will be computed and used as the default range

Align

Command: align     Automatically align geometry to grid

Input file command:   align
Command line options: -a
Command Description:

The align option will attempt to orient the Cartesian grid with the main dimensions of the geometry. This is done by defining a tight bounding box around the geometry using an optimization procedure where the objective is to minimize the difference in volume between an enclosing box and the geometry. Using the align command will override any bounding box parameters previously entered and will build an "aligned" bounding box around the full geometry. It is currently only implemented for STL geometry and will ignore any other diatom definitions. Note that this option will also write temporary stl and diatom files to the working directory.

Bounding Box Expansion Factor

Command: bbox_expand     Expand tight bbox by percent

Input file command:   bbox_expand <arg>
Command line options: -be <arg>
Argument Type:        floating point value
Command Description:

Sculpt will measure a tight bounding box of the input model and expand the box by the specified percentage in x, y and z. Input value can be any positive or negative floating point value where 1.0 represents 100% expansion. If not specified, the default will add about 2.5 cell widths to the bounding box on each side. This option should be used with the cell_size option. It will be ignored if a specific bounding box has been defined (ie. xmin, ymin, etc...).