Skip to documentation
BRL-CAD
DocumentationAll documentsEnglish

EDARB(nged)

NAME

edarb - edit ARB primitive faces, edges, and vertices

On this page

SYNOPSIS

edarb edgedir  arb edge delta_x delta_y delta_z
edarb edgedir  arb edge rot fb
edarb extrude  arb face distance
edarb facedef  arb face [a|b|c|d parameters]
edarb mirface  arb face axis
edarb permute  arb tuple

DESCRIPTION

The edarb command provides subcommands for directly editing ARB (arbitrary polyhedron) primitives by moving edges, extruding or redefining faces, mirroring faces, or permuting vertex numbering. The arb argument names the ARB object to edit.

Subcommands

edgedir arb edge delta_x delta_y delta_z

Move the specified edge of arb by the given delta vector in model coordinates. The edge is identified by its 1-based index number. All planes affected by moving the edge are recalculated to remain planar.

edgedir arb edge rot fb

Set the direction of the specified edge using rotation angle rot and front-back angle fb (both in degrees). The edge is moved in the computed direction.

extrude arb face distance

Project the specified face of arb outward by distance (in current working units) along the face normal, extruding the ARB shape. Only available for ARB4, ARB6, and ARB8 types.

facedef arb face [a|b|c|d parameters]

Redefine the specified face of arb by providing a new plane definition. The face is identified by the product of its vertex numbers (e.g., face 1234 uses product 24). The plane definition method is selected by a letter:

  • a — planar equation: A B C D (normal vector components and offset)

  • b — three points: X1 Y1 Z1 X2 Y2 Z2 X3 Y3 Z3

  • c — rotation/front-back angles plus a fixed point or vertex

  • d — same plane normal direction, but shifted through a new fixed point

If fewer arguments than needed are provided for the chosen method, the command prompts for the missing values (interactive mode).

mirface arb face axis

Mirror the specified face of arb across the specified axis (x, y, or z).

permute arb tuple

Permute the vertex numbering of arb according to the specified tuple, which specifies the new vertex ordering. The minimum tuple length varies by ARB type (ARB4: 3, ARB5/6: 2, ARB7: 1, ARB8: 3).

EXAMPLES

Example 1. Move an edge using a delta vector

mged> edarb edgedir arb8_1 12 10 0 0

Moves edge 12 (between vertices 1 and 2) of arb8_1 by +10 units in X. All affected face planes are recalculated.

Example 2. Move an edge using rotation angles

mged> edarb edgedir arb8_1 12 45 0

Sets the direction of edge 12 using azimuth 45°, elevation 0°.

Example 3. Extrude a face

mged> edarb extrude arb8_1 1234 50

Projects face 1234 (vertices 1, 2, 3, 4) of arb8_1 outward by 50 units.

Example 4. Redefine a face by plane equation

mged> edarb facedef arb8_1 1234 a 0 0 1 100

Redefines face 1234 of arb8_1 to be the plane with normal (0,0,1) at offset 100 (i.e., Z=100 plane).

Example 5. Mirror a face

mged> edarb mirface arb8_1 1234 z

Mirrors face 1234 of arb8_1 across the Z axis.

Example 6. Permute vertex numbering

mged> edarb permute arb8_1 321

Permutes the vertex numbering of arb8_1 according to the tuple 321.

SEE ALSO

arb(nged), sed(nged)

AUTHOR

BRL-CAD Team

BUG REPORTS

Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org