*ellipsoid

Creates a solid in the shape of an ellipsoid.

Syntax

*ellipsoid center=<value> a_dir=<value> b_dir=<value> a=<value> b=<value> c=<value>

Type

HyperMesh Tcl Modify Command

Description

Consider the general equation of an ellipsoid centered at x0, y0, z0 as

(x−x0)2/a2 + (y−y0)2/b2 + (z−z0)2/c2 = 1

This ellipsoid’s principal axes are aligned with x, y and z directions. In this command, an ellipsoid is created whose principal axes are aligned in any specified direction. User defined directions are given for the principal axis that is associated with a value in a_dir, and the principal axis for b value in b_dir values. The principal axis for c value is determined by the other two directions.

Inputs

center=<value>
The center location of the ellipsoid.
a_dir=<value>
The principal axis direction associated with ‘a’ value. A vector input is expected.
b_dir=<value>
The principal axis direction associated with ‘b’ value. A vector input is expected.
a=<value>
The ‘a’ value in the ellipsoid equation.
b=<value>
The ‘b’ value in the ellipsoid equation.
c=<value>
The ‘c’ value in the ellipsoid equation.

Examples

To create an ellipsoid solid centered at (1,1,1) with principal axis for ‘a’ as (1,1,0), with principal axis for ‘b’ as (0,0,1), a=4, b=5, and c=6 values: 
*ellipsoid center="1.0 1.0 1.0" a_dir="1.0 1.0 0.0" b_dir="0.0 0.0 1.0" a=4 b=5 c=6

Errors

Incorrect usage results in a Tcl error. To detect errors, you can use the catch command:
if { [ catch {command_name...} ] } {
   # Handle error
}

Version History

2025