AO very slow

This scene with no textures and just one lamp takes forever to render with AO, I waited 20 min and not even the smallest amount of progression took place. I have AO set on 16 samples but still I have rendered scenes with AO that were way more complicated than this before and it didnt show this little of progression. Is there any buttons or tricks to speed this up, or do scenes with lots of little sharp shadows like this just take forever?


Have you tried out different octree values found in Render\10 pixels to right from Key in the down? More info here:

AO is a lot quicker with Yafray. The internal Renderer works in certain situations - especially in large scale setups - quite slow with Raytracing.

I think it may be the large size of the ground plane. Try removing it and seeing if it renders faster. If it does, then put it back and give it a new material, turn off traceable. That will stop AO from calculating the shadows from it, which takes a long time. Wherever you have objects on or intersecting that plane, place small planes just underneath the ground plane with traceable on. Also you can turn on the “distances” setting to 2 or 3, that will speed things up a bit.

Also… AO may be “a wonderful thing,” but I seriously doubt that it will do a whole lot for you here. The lighting in this “wide open space” is plainly going to be nothing that an ordinary directional spotlight could not handle. You could even use ambient lighting.

What you need out of the light is simply “good, even illumination of the entire scene.” And what you need out of the darkness is “sharp, crisp shadows in a few well-established places,” such as the wall and the railings. Getting the light is easy. One cheap and simple way to do the darkness is with a shadow-only spotlight.

What you care about in an image … all you care about … is how it finally looks when it’s done, and of course, how long it takes you to get an acceptable result. An image does not have to be realistic, in every concievable aspect, to look realistic-enough to the eye.

Thanks for the help, I switched to yafray and it seems to be working much better. You can see the scene here, this is not the final light set up.


That object (or wall) could probably pass with a BumpMap instead of all that complicated meshing.