Extrusions

An extrusion is one or more 2D closed figures in the xy plane, extruded between two z-values. Any figure after the first represents a non-touching, non-intersecting hole in the parent figure. The definition is as follows:

    EXTR <n_children> <z1> <z2>

Example

    EXTR 1 100.0 200.0

An extrusion is defined using the EXTR keyword, followed by the number of figures making up the extrusion and the two z-values between which the figures should be extruded. Two types of figures can be extruded: the 2D polygon and the circle.

A 2D polygon is a closed geometry lying in the xy plane, made up of unique points which form non-intersecting straight edges. The definition uses the keyword 2DPG followed by the number of points in the polygon. The points themselves follow, on multiple lines, if required:

    2DPG <n_points>
    <x1> <y1> ... <xn> <yn>

Example

    2DPG 4
     1000.0   1000.0
    -1000.0   1000.0
    -1000.0  -1000.0
     1000.0  -1000.0

    or 

   2DPG 4 
   1000 1000 -1000 1000 -1000 -1000 1000 -1000

A 2D circle is a circle which lies in the xy plane, with an optional parameter defining the number of chords that may be used when rendering it.

   2DCR <x> <y> <radius> [<sides>]

Example

   2DCR 300.0 400.0 125.0 16