OrientCrystalBlock (
        a,
        b,
        c,
        z,
        y,
        x,
        )

The tree sides of a block of size a,b,c rotated around z,y,x

RotMat (
        z,
        y,
        x,
        )

Rotation matrix Zrot(z)*Yrot(y)*Xrot(x)

display ( evcfilename,  hab )

Create a 3D manipulator view of the crystal habitus and the optimized form

displayblock (
        a,
        b,
        c,
        z,
        y,
        x,
        canv,
        )

Add a display of the block described by a..x to the 3D canvas canv

displaysphere ( d,  canv )

Add a display of the sphere with diameter d to the 3D canvas canv

fromabsorb (
        evcfilename,
        hab,
        xe=None,
        )

Use an optimization to find the best crystal form fitting the hab.

The result is putten in the given XtalEvc object xe. If xe is not given, the evcfilename is read, modified, and written.