Before starting with the geometrical models, it is recommended to work with the Units that fit the most to the dimensions of the geometry, as some parameters are automatically set-up. The following functions are especially sensitive to the working Units:
In this example, the default Units (Meters )is valid.
First, to build a dihedral create two plane surfaces. It is available within the Geometry –Surface – Plane menu, Figure 1, or by using the plane command. As shown in Figure 2, the first corner of the first plane is (-0.5, -0.5, -0.5) and the first corner of the second plane is (-0.5, -0.5, 0). The second plane will be rotated 90º and move from (0, 0, 0) to (-0.5, 0, 0).
Figure 1: Surface menu.
Figure 2: Dihedral.
Revise the normal vectors of the geometry by clicking on the Normals icon. The normal vectors must be as shown in Figure 3.
Figure 3: Normal vectors verification.
To build easily a trihedron creates a box of 1m x 1m with its first corner in (0, 0, 0). It is available within the Geometry –Solid – Box menu, Figure 4, or by using the box command. Rotate the box -45º around the z axis. Finally, explode the geometry by using the explode command and delete three surfaces by using the delete command. The geometry is shown in Figure 5.
Figure 4: Box menu.
Figure 5. Trihedron.
It is necessary to correct the normal vectors by clicking on the Normals icon and then choose the direction clicking on the geometry. Also, invertNormals command can be used to perform this task. The final result per each surface will be as shown in Figure 6.
Figure 6: Normal vectors.
To build a cavity creates a box of 1m x 1m with its first corner in (-0.5, -0.5, -0.5). Explode the geometry by using the explode command and delete one surface by using the delete command, as is shown in Figure 7.
Figure 7: Cavity
Be sure that the normal vectors are as shown in Figure 8:
Figure 8: Normal vectors verification.
In order to consider the reflections within the cube, it is necessary to duplicate the normals of the geometry. It is available within the Simulation –Duplicate Normals menu, as shown in Figure 9.
Figure 9: Duplicate normal vectors.