Problem with Ambient Occlusion rendering (Noise - Pixelated)

I’, new to Blender, and am trying to render a floor plan for an office building. Problem is when I use Ambient Occlusion for lighting, when I render the scene looks very distorted and pixelated, no matter how many samples I use. I attached the file. Can anyone help?


5th Floor - Problem.blend (825 KB)

You have masses or overlapping faces giving the dark pixelated areas. You really need to clean up your meshes.

Is there an easy way to clean this up?

Is there an easy way to clean up the data?

1). Use the ‘remove doubles’ operator.
2). If number one doesn’t work, you may have to delete some of the faces and reconstruct the area using ‘F’.

The phenomenon you see is called ‘Z-fighting’ and the vast majority of raytracers cannot successfully reconcile the situation automatically, which is why it requires user attention.