Block the beam branch with specific beam index

[lyuqinshu]

In the original package there is no way of controlling the beam propagation

from PyOpticL import layout, optomech
import FreeCAD as App

base_dx = 200
base_dy = 200
base_dz = 100
gap = 3
inch = layout.inch
spacing = 25

def demo_layout(x=0, y=0, angle=0):
    bp = layout.baseplate(
        base_dx, base_dy, base_dz,
        x=x, y=y, angle=angle,
        gap=gap, optics_dz = 50,
        name="demo",
        label="demo",
    )
    bp.metric = True
    layout.set_max_beam_index(1024)  

    beam = bp.add_beam_path(x=100, y=base_dy, angle=layout.cardinal['down'], color=(1.0, 0.0, 0.0))

    bp.place_element_along_beam("HWP1", optomech.waveplate, beam,
                                       beam_index=0b1, distance=50, angle=layout.cardinal['down'],
                                       mount_type=optomech.rotation_stage_rsp05)

    bp.place_element_along_beam("PBS1", optomech.cube_splitter, beam,
                                       beam_index=0b1, distance=50, angle=layout.cardinal['left'],
                                       mount_type=optomech.skate_mount)
                                                                                                         

    return bp

if __name__ == "__main__":
    demo_layout()
    layout.redraw()

This produces a beam that is split by the cube.

Now with this patch you can turn off a specific branch. Add this after beam instantiation

beam.BlockedBeams = [0b10]

You can get pure reflection.