How to use only direct light?

Question

I want to create a viewshed analysis with Blender. Something like this:

I tried it using light in Blender Render and Cycles but I can't get it to work due to the light fall off. I have already set the light bounces to 0.

Answer 1

You can do that easier in a compositing step.

1. Choose whichever renderer.
2. In the Rendering Tab of the Properties Editor, activate the Shadow Pass.

The shadow pass hold exactly that information: where light hits and where not. The intensity isn't relevant. It is also antialiased.