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These subobject types are available:

 

Rectangle

These objects can be defined in two ways:

 

1.

Define the center and the two perpendicular vectors that span the rectangle (as described in the section about rectangular interfaces). In this case the definition line has to start with the keyword 'Rectangle vectors'. Then the location and the two directional vectors follow, as in the following example:

 

rectangle vectors        -2        0        -5        1        0        0        0        0        1

 

Note that the coordinates must be separated by tab stops if they are stored in text files.

 

2.

Sometimes it is more appropriate to specify the four corners of a rectangle. This can be done using the keyword 'Rectangle points' which must be followed by the coordinates of the four corners. In order to get the correct surface normal you can work with the following trick:

•Imagine you sit in the center of the rectangle

•Move up a little along the wanted surface normal

•Turn around and look back on the rectangle below you

•Start with one of the corners as first point and then add the others counterclockwise

An example of this data format is this:

rectangle points                0        0        0        2        0        0        2        5        0        0        5        0

 

Triangle

Here you have two possibilities as well, using spanning vectors or end points:

 

1.

As described in the section about triangular interfaces, the triangle is defined with a vector to one of the corners as a reference point and the two vectors from that point to the remaining corners. The surface normal is given by the cross product of the two vectors. Here is an example:

 

triangle vectors                0        0        -5        1        0        0        0        0        1

 

2.

You can also write down the three corners, using the same orientation rule as explained for rectangles (see above). An example is given here:

 

triangle points        0        0        0        2        0        0        2        5        0

 

Circle

Circles are defined by their center, their surface normal and the radius:

 

circle        -3        0        0        0        0        1        0.34

 

Sphere

Spheres are simple defined by the center coordinates followed by the radius:

 

sphere        -3        0        0        0.5                                                                

 

Cylinder

This object type is a closed cylinder, defined the usual way by specifying the center, the radius vector and the axis vector:

 

cylinder                20        0        0        0        0        1        4        0        0                        

 

Ellipsoid

This subobject type defines full ellipsoids, specified by the center and the three principal directions:

 

ellipsoid        -10        0        0        0        0        2        0        2        0        0        0        3

 

Cone

This subobject type defines a cone, specified by the two end points and the corresponding radii of the circles at each end:

 

cone                -5        0        0        5        0        0        2        0.5