While it is true that you can only have one sender object per rfluxmtx calculation, Technically, you can specify as many "receiver" objects as you like; like in this case, all one run of the windows in a given room. The sender rfluxmtx, in this case is replaced by your selection of points, as is normal for a view matrix calculation. windows. To include multiple receivers, you You need to specify the output file ahead of each window's window polygon using the

#@rfluxmtx o=output.mtx

the "#@rfluxmtx o=output.mtx" variable as described in the man page at https://radiance-online.org/learning/documentation/manual-pages/pdfs/rfluxmtx.pdf

The view matrix calculation will also be more efficient if you can avoid running don't need to run it separately for each window in this way. window.

While you did not ask, you do need However, it is generally necessary to run rfluxmtx once per elevation (i.e., direction) separately to calculate the external "daylight" matrices matrix connecting the building each window exterior to the sky, since the sky (+ground) sky. The exception to this is in this case the only receiver. Normally, this means running rfluxmtx once per window. A shortcut is possible when there are few nearby obstructions outside the building, and the windows all lie in a plane that you can assemble as a single "source" for that elevation, "source," even though they may be physically separated by mullions or wall sections. Again, it will be more efficient to combine calculations in this way, when possible, but it is not required by b the method.

The tutorial recommended by JChen remains the authoritative source.

Best, -Greg