# Why is driven attribute not updating?

Trying to animate an object's material, by simply changing its opacity.

As there is no way to directly change the material properties in the AN node tree, I created a driver to change the value of Transparency's "Alpha".

So, the execution flow goes like:

1. "Object Attribute Output" creates/change a property named "alpha" within the object;
2. this property is used by the driver to...
3. set that object's material transparency.

In theory this should work, but:

• it works with text objects;
• it does not work with any other type of object.

Am I doing something wrong? Or is this supposed to be that way?

What you can do is to control the transparency of the material directly by using active_material.alpha as path in the Object Attribute Output node.
• Nice! active_material.alpha does the trick - and without a driver! Thanks! But I think I'll leave the question open till solved the mystery of the driver? – Ricardo Roehe Nov 23 '16 at 11:37