Fade in action applicable to all objects (in cycles) I am trying to make a schematic video about assembling a machine. For a lot of objects (bolts, etc...) I use the same delta location action, so they get assembled in their position. This allows me to use the NLA editor, to make almost all the animations.

The problem is when I try to fade in &amp; fade out objects. Loc, rot &amp; scale works well, because all objects share these properties. But transparency depends on the material.

I've tried to have all materials end with a mix node connected to a transparent shader. So with the 'Fac' slider I can animate the fade. But the result action can't be shared between different objects, as they have different materials. 

So, is there any visibility property of object I can animate? This would be great for motion graphics too.

Thanks
You could use a node group to do this:


Add a mix shader and create a new node group by selecting it and pressing CtrlG
Add a transparent shader to the node group:


Add this node group at the end of all the materials you want to simultaneously fade in/out:



This process can be made a little bit faster with copy and paste:


Select the node group and press CtrlC
Select each object/material and press CtrlV to paste the node group.

Adjusting the Factor of the mix node inside the node group will set it for all instances of the node group


With the factor set at .5 and .8 (click for larger image):