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 & fade out objects. Loc, rot & 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.