To detach a material from an object click on Radiance—>Materials—>Detach Material. Then select the object from which you want the material detached.
This tool can be used in conjunction with the "Show all attached materials" function making it possible to select and detach all the materials in a drawing at one time. To do this go to Radiance—>Materials—>Show All Attached Materials. When all surfaces are selected go to Radiance—>Materials—>Detach Material. At the prompt it will ask you to select surfaces to detach materials. Type the letter P for the previous selection set, all surfaces with materials will be selected and highlighted, then hit <enter>. All materials will be detached.
