This is a work in progress for a project of João Cesário, the author of Aura Mecânica, a b&w comics that he is now managing to convert it to a 3D animation movie.
You can follow the development in the facebook page or and in the portuguese blender forum and you can help by modelling some of the missing characters and props.
This is my small contribution for the project so far, I've modeled this character, "Robot da construção civil" from his reference drawings.
It still needs some touches and the rigging but it's almost done. The final renderings will be in black and white with a technique developed by Paulo Martins.

So I've finally finished the short demo of the Laser Sheet OSL shader to simulate a laser sheet illuminating the objects in a scene.
In order to use it you must use Cycles, with the OSL option enabled. Add a script node and choose the LaserSheet text file.
You should end um with something like this:

You just have to connect the laserout node to an emmission shader which is then added to the original base shader of the object. In this case I've used the same material for all objects, with a random RGB value node group that I've created some time ago in order to have some variation in the scene.
In the script, we have two inputs for the laser thickness and laser intensity (do not use high values...), 3 inputs for the laser origin, 3 inputs to define the normal to the laser sheet plane. ( 0,0,1) will be a horizontal plane (XY plane), (1,0,0) will be a YZ plane, (0,1,0) will be a XZ plane, but you can use other values).
You can input all these values by hand but in order to create an easier and more visible way of where the plane will be, I've introduced 3 empties in layer 2 which define the origin and the orientation of the laser plane. After placing these as we want, just run the python script "LaserUpdate" and the input values of the OSL script will be updated accordingly (insert then keyframes as needed). You should de-activate layer 2 when rendering since the auxiliary plane will act as an obstacle interfere with the script. 
So here's a demo of what can be done with this OSL shader and you can download the .blend file here.

UPDATE! (04.01.2012) - An updated .blend file can be found here with an easier way to define the laser position and orientation from a plane, thanks to SlykDrako who did it using drivers and a python script. The plane might interfere with the laser sheet by creating shadows. Disable layer 2 when rendering if needed.

In the last days I've been trying to create a material that would give a random color to each object with that material. Since Blender version 2.64 there is a material node of "Object Info" which has a random value for each object. The problem is that to define a color we need at least 3 values (RGB, HSV, etc...). 
I was trying to do it with python scripting but without success. At first, the maximum I could do was a script to create a random color for every material with a name starting with "rnd" and it was quite simple, but it needs a different material for each object.

import bpy, random
a=bpy.data.materials
for mat in a:
      if mat.name[0:3]=='rnd':
            node=mat.node_tree.nodes['Diffuse BSDF']
            RGB=(random.random(),random.random(),random.random(),1)
            node.inputs['Color'].default_value=RGB

But after thinking about it for a few hours, I finally came with a solution, by extracting 3 random values from the random value of the object. So if the random number is for example 0.123456, I take the value of 0.12 for R, 0.34 for G and 0.56 for B. I think it is ok as you can test with this example image. You can try it by yourself with the node group in this Blend file.