How to make material semi-transparent in Cycles? I have a simple shader with a water texure and I'd like to make it semi transparent.  Using Blender Internal engine, you can do this just by setting the alpha value on the shader.  Is there a way to do something similar in cycles?
To make a semi transparent texture, place a diffuse and transparent shaders in the input of a mix node in the node editor.


To make water, use the glass shader and play around with the node values.