Transparent material based on thickness of mesh

I am trying to create a material (with cycles) that becomes more transparent where the mesh becomes thinner. I plan on making the material to be applied on splashing paint to get a similar effect as this:



Notice that where the paint is thinner, you can see through it more than where it is thicker. How can I make this type of material? I have tried experimenting to get this type of material, but haven’t gotten the right result.

Thank you for any help.

In the cycles node setup, try plugging a ‘Volume Absorption’ node into the ‘Volume’ of the material output.

This alone creates a basic transparent material with more transparency as the object is thinner (the absorption effect)

edit: here is an example of a node setup that creates that sort of look


Something as radical as this?

Thank you both for the help! The volume absorbtion node is currently only in the daily build of Blender, right? I will experiment with this to try to get the right result. Thanks again.

Or u can use the Blenderdiplom technique:


It can be faster.