Your topic states, " Not bitmap manipulation", however, material animation is the only animation option available to THERE developers at the time of closing 2010.
Jinxed_Karma's sign uses material animation.
This may help you determine if material animation can help you achieve the effect you are looking for.
It looks like the sign model is actually in the three positions. 1 in LOD0, 2 in LOD1, etc. Is the "loop" set to actually rotate between the LOD's or something?
This is where I am getting confused between the model aspect, and the bitmap I guess.
Just a comment on Greenie's link for the There Wiki in the Web Archive - Ian Young is still hosting the There Wiki, so it's still online - here's the link for the same information about Material Animation: www.iay.org.uk/there/wiki/wiki.pl?MaterialAnimation
Just a comment on Greenie's link for the There Wiki in the Web Archive - Ian Young is still hosting the There Wiki, so it's still online - here's the link for the same information about Material Animation: www.iay.org.uk/there/wiki/wiki.pl?MaterialAnimation