Is there any way to control materials in real time? If possible I would like to create a material using the node set up and depending on the property value fade in or out the strength of one of the nodes.
You can use an IPO to change the Object color value of the material.
In the node editor you can use that material (with the IPO) as a filter for other materials.
Then you can use properties to control the IPO.
Interesting, sounds a bit hacky but I’ll have to experiment with it later on! I guess this means you can only have one input then? Or maybe 3?
Well, the IPO contains Red Green and Blue values so using an RGB split node you can have upto 3 input values.
Of course things are gonna get slow it it is too complex.
http://blenderartists.org/forum/showthread.php?t=201295
Here is an example I did where the colour change drives the alpha value, all driven by a property.