# rblock create command

Syntax

rblock create keyword ...

Primary keywords:

Create a single rigid block with the specified attributes. A model domain must be specified prior to rigid block creation. The rigid block will not be available for replication. Unit density is assumed at creation unless the density keyword is given. The inertial attributes are automatically computed due to the rigid block geometry.

Note

• A model domain must be specified prior to rigid block creation.
• While cycling, rigid blocks can only be created before cycle point 0 (i.e., when the timestep is calculated).
box fxmin fxmax <fymin fymax > (z-components are 3D ONLY)

Create a rigid block in the shape of an axis-aligned box. Following specification of the box in the $$x$$-direction, if subsequent extents are omitted, then the latest specified extent is used.

circle keyword ... (2D ONLY)

Generate a closed circular rigid block in 2D.

position vpos

Position of the center of the circle that is the origin by default.

Radius of the circle that is 1.0 by default.

resolution fres

Resolution of the facets. The number of facets is set so that the facet length is smaller than fres * frad. By default, fres = 0.1.

cone keyword ... (3D only)

Create a conical rigid block in 3D.

axis v3

Direction of the symmetry axis of the cone pointing from the base position that points in the positive z-direction, by default.

base v3

Position of the base of the cone (i.e., the center of the bottom end) that is the origin, by default.

height fh

Height of the cone. This is the distance from the base position to the point or, if a frustum, to the center of the top end. By default, fh = 1.

Radius of the cone. By default, fbot = 1.0 and ftop = 0.0, meaning that a cone is created. If ftop > 0.0, then a conic frustum (i.e., cone with the tip cut off) is created. In this case, fbot is the bottom radius at the base location, and ftop is the radius of the top of the frustum at a distance fh from the base location along the symmetry axis.

resolution fres

Resolution of the edges of the cone ends. The number of end edges is set so that the edge is smaller than fres * fbot. If a frustum is to be generated with ftop > 0, then the end edge lengths are less than fres * min(fradbot, ftop). By default, fres = 0.1.

cylinder keyword ... (3D Only)

Create a cylindrical rigid block in 3D.

axis v3

Direction of the symmetry axis of the cylinder pointing from the base position.

base v3

Position of the base of the cylinder (i.e., the center of the bottom end) that is the origin, by default.

height fh

Height of the cylinder. This is the distance from the base position to the center of the top end. By default, fh = 1.

Radius of the cylinder, or the distance from the axis of symmetry to the side.

resolution fres

Resolution of the edges of the cylinder ends. The number of end edges is set so that the edge is smaller than fres * frad. By default, fres = 0.1.

density f

Rigid block density with default value 1.0.

from-geometry <set > <range>

Create a rigid block from the vertices of polygons in a geometry set. If no set is provided then the current set is used. The optional range is applied to polygons in the specified set.

group s <slot slot > ...

The group name at slot slot is set to s for the newly created rigid block. If slot is not specified, then the group name at slot Default is set to s.

id i

Rigid block ID. If not specified, then the next available ID is used.

rounding <relative> f

Introduce rigid block rounding. Rigid blocks are represented by a core shape that is composed of {linear facets in 2D; triangular facets in 3D}. The core shape is convex, closed and manifold. When rounding is nonzero, the core shape is expanded in a directions by a {circle in 2D; sphere in 3D} of a specified radius with center passing along all points on the exterior of the core shape. The value of the rounding corresponds to the radius of this expansion {circle in 2D; sphere in 3D}. If the relative keyword is given, the rounding is computed as the product of f and the radius of a {circle in 2D; sphere in 3D} with the same size as the rigid block. When the rounding is changed so are the inertial properties.

sphere keyword ... (3D ONLY)

Create a spherical rigid block in 3D. The sphere is created by refining an icosahedron (i.e., a sphere composed of 20 identical equilateral triangles) so that the edge lengths are smaller than a length defined by the resolution keyword.

position vpos

Position of the sphere centroid that is the origin by default.

Radius of the sphere that is 1.0 by default.

resolution fres

Resolution of the facet edges. The number of facets is set so that the edge length is smaller than fres * frad. By default, fres = 0.1.

vertices v1 v2 ...

Specify the vertices of the rigid block. The convex hull of the input points is computed and the rigid block is created from the convex hull.

Example Usages

Create a box-shaped rigid block with dimensions specified with FISH variables and inline FISH statements.

rblock create box [xpos-rad] [xpos+rad] [ypos-rad] [ypos+rad] [zpos-rad] [zpos+rad]


Similar to above, using inline FISH to obtain calculated dimension values.

rblock create box -1 1 -1 1 [8-1] [8+1]


Create a rigid block from vertices.

; block 8
rblock create vertices ...
6.500000e+000 1.000000e+000 2.200000e+001 ...
6.500000e+000 0.000000e+000 2.200000e+001 ...
6.500000e+000 0.000000e+000 2.400000e+001 ...
6.500000e+000 1.000000e+000 2.200000e+001 ...
5.500000e+000 1.000000e+000 2.200000e+001 ...
5.500000e+000 0.000000e+000 2.200000e+001 ...
5.500000e+000 1.000000e+000 2.200000e+001 ...
5.500000e+000 1.000000e+000 2.400000e+001 ...
5.500000e+000 0.000000e+000 2.400000e+001 ...
6.500000e+000 1.000000e+000 2.400000e+001 ...
6.500000e+000 0.000000e+000 2.400000e+001 ...
5.500000e+000 0.000000e+000 2.400000e+001 ...
5.500000e+000 0.000000e+000 2.200000e+001 ...
5.500000e+000 0.000000e+000 2.400000e+001 ...
6.500000e+000 0.000000e+000 2.400000e+001 ...
5.500000e+000 1.000000e+000 2.400000e+001 ...
5.500000e+000 1.000000e+000 2.200000e+001 ...
6.500000e+000 1.000000e+000 2.200000e+001


from the file “rigid_blocks.dat” called in Rigid Block Model of Flying Buttresses