Hello! :) I have never created a demo before but im going to give it a try with my newly completed software renderer. So i was wondering if anyone could recomend some cool effects which are not to complex to implement and would be suited for a software renderer (it currently supports gouraud, texturing, envrioment mapping). As i said im completely new and clueless to creating cool visual effects and any input is appreciated! Someone suggested rendering a particle effect to a texture, would that be cool? Thanks in advance! *off to study some demos*

I sugest you download some old demos form scene to get some ideas. But since it's SW renderer yo might want to play with frame buffer postprocessing.

I agree, you could play with motion blur to create some nice effects and an illusion of realism. You could create tunnel effects too, and particle effects (combined with motion blur)...

You probably wont want to implement things like normal mapping and dynamic per-pixel lighting, even if it looks cool, since that would make your renderer much slower... And it will probably be quite slow already (at least compared to hardware renderer). It could still be possible to have decent per vertex lighting, however.

Aye, postprocessing can produce some very interesting results. There's the oh-so-fashionable 'bloom' filter - easy to do, doesn't require HDR or anything like that - and also things like edge detection.

Best place for inspiration is to play with your Photoshop Filters / GIMP Plugins to see which effects look cool and could probably be run in realtime. :)