Hi,
In the meantime if you have ccp4 installed, sfall will calculate the structure factors, which you could display as above or with ccp4.
phenix.fmodel does this too - it will also include bulk solvent. I'm not sure if this is important for the intended use; I wouldn't expect reflections from a fake small-molecule crystal to be visually similar to those of real macromolecular crystals anyway.
This kind of exercise i good for educational purposes. For example make a model with 5 atoms, say alanine arbitrarily placed in a p1 cell. Now make an "omit" model whier one atom is missing. Calculate Fc and PhiC from both and combine them to make a map in various ways, using resolution 0.5 so each atom makes a peak. Does the omitted atom really show upat half-height in the Freal-PhiC and Fc-Phi-real maps? full height in the 2Fo-Fc map? Or switch it and say 4 atoms is the real structure, 5 is the model- does the extra atom disappear in the 2Fo-Fc map and show up negative in the Fo-Fc? (OK, the last two are obvious and don't need demonstrating) Or explore the limits of resolution imposed by the smoothness of atomic orbitals: calculate Fc at successively higher and higher resolution, use sfcheck to calculate the optical resolution, and explain why it doesn't go below about 0.5 A, and what happens if you give all the atoms B-factors around 80.
That's exactly how I did most of the slides (that show maps) here: http://www.phenix-online.org/presentations/latest/pavel_maps.pdf Pavel