## Mirror Symmetry

Mirror symmetry constraint can be set for three geometric objects. The
first and second objects are mirror reflections of each other relative
to the third object, it is a line that determines the symmetry axis.

A symmetry constraint can be created by the

```cpp
constraint_item GCE_AddSymmetry(GCE_system gSys, geom_item g[2], geom_item lObj)  
```