Hello Dwight,
You wrote: "Archicad 10 does not show transparency in the 3D window - you must render to see transparency."
In what sense do you mean this ?
I can turn ON or OFF transparency in shading in the 3D window in AC 10.
Thanks,
Peter Devlin
Another option for semi-invisibility is to set the object's layer to WIREFRAME in the layer settings / combination. I do this occasionally for glass balustrades in elevations.