Furrify.lsc is an Image Filter LScript that applies random fur-like lines to a rendered image. This is not a full-blown fur plug-in. Since the lines are random, it's meant for stills only. Also, the lines are not antialiased. But it can give quick results in a snap, and it's free!
Let's pretend that this is a highly detailed architectural rendering of a new building. Let's say it looks fantastic, but the lawn looks awfully flat. Wouldn't it be nice if we could just paint some grass on there? Well, Furrify will do that for you.
Okay, how do I apply Furrify?
Furrify.lsc is an Image Filter LScript. So, go to the Effects menu and apply the LS/IF-RT Image Filter plug-in. Click on the Options button and select Furrify.lsc. There should be a short pause as Furrify allocates some memory.
Furrify requires that you render using only one segment. So, go to the Camera panel and set the Segment Memory high enough so that it only uses one render segment.
Then, go to your Grass Surface. Go to the Advanced Options tab and click on Special Buffers. Under the LS/IF-RT heading, type in the length of lines you want (in milimeters). I used 100 here. That's 10 centimeters.
Furrify works by drawing a 3D line starting at every pixel with a value in the Special Buffer. The color of the line is just the color of the start pixel, so it's like it smudges it out in a line. Oh, and the direction of the line is based on the normal of the surface at that pixel, with a little randomness added.