Motion Blur problem...
 

I can render frames fine without but everytime i turn on motion blur and render the frame its all black except for the animated objects.. any ideas on whats causing this??

I belive there thinking if your useing motion blur then your probably rendering in layers also.

acrtually i have no clue.. im completely new to this..

It's been a while, but I don't think you can motion blur software particles. Isn't that how it goes? You have to composite it in layers afterwards.

but there is no particles in this scene... unless you include the bump textures...

Well my thinking is this. Some one stop me if I'm wrong. only the moving object are rendered with motion blur on becouse if the none moving objects were it would make the exposure wrong. Just how the computer dose it. and / or it would slow things down even more. Some renderer's the bojects that move many times to get a 3d motion blur.

When you step in to useing motion blur with your sean, you must composit. Meening render you back ground Plat or animation and composit it with the animation of the moving objects. Render that part in a nother pase with alfa and put them togather. If your rendering out to frames and putting them togather with a nother app whitch is the best if you ask me.. you can eather use that app, or if it dosn't do the job good enufe for you, you can batch it in phtoshop.