rblock densify command

Syntax

rblock densify keyword ... <range>

Primary keywords:

aspect-ratio    iterations    facet-group    length-maximum    normal    random    size    tetrahedra    triangle

Densify rigid blocks via cutting. Densification (without the tetrahedra or triangle keywords) is the process of cutting a rigid block through its centroid to create two rigid blocks. Densification by cutting is recursive until no rigid blocks fall within all of the selection criteria or the specified number of iterations is met. By default, the direction of the cut is perpendicular to the direction of highest aspect (i.e., the longest direction) of the rigid block. One can densify in a fixed direction as well. In addition, a degree of randomness about the selected orientation can be chosen. If the iterations keyword is not give, a rigid block is selected if it fits any of the selection criteria. Using the tetrahedra or triangle keywords changes the algorithm to cut {tetrahedral in 3D; triangular in 2D} rigid blocks so that the resulting rigid blocks retain the overall shape as described below.

Note

• Only the core shape is cut.

• While cycling, rigid blocks can only be cut before cycle point 0 (i.e., when the timestep is calculated).

aspect-ratio f

Specify that rigid blocks with aspect ratio greater than f are selected for densification.

iterations i

Specify the number of maximum number of iterations for cutting. One iteration is a densifying loop through all rigid blocks. If the number of iterations is specified all rigid blocks in range are densified.

facet-group s <slot slot >

Apply the group s in slot slot to the facets cut during densification.

length-maximum f

Specify that rigid blocks with maximum length (i.e., the length of the rigid block in the longest direction) greater than f are selected for densification.

normal v

Cut using a plane with normal v. Randomness about this normal can also be specified with the random keyword.

random <f >

Specify that randomness, in degrees, of the cut orientation. If no f is given, the cut orientation is drawn from a uniform distribution covering all orientations. If f is given, the normal of the cut plane is chosen randomly so that it is within f degrees of the original cut plane.

size f

Specify that rigid blocks with {area in 2D; volume in 3D} greater than f are selected for densification.

tetrahedra (3D ONLY)

Cut tetrahedral rigid blocks in range into 8 tetrahedra. First cuts are made through the midpoint of each edge, resulting in four new tetrahedra and an octahedron in the center. The octahedron is then split into four tetrahedra with two further cuts along the diagonals.

triangle (2D ONLY)

Cut triangular rigid blocks in range into 4 triangles. Cuts are made through the midpoint of each edge, resulting in four new triangles.