What are "Visibility culling animations"?

Hopefully simple, I would just like some help understanding this warning message I'm seeing in the console:

"Multiple visibility culling animations in the same hierarchy, animation culling for animation component in Player will be turned off."

I would like to know what it means - what is a visibility culling animation, how do I tell that I have more than one, and is that an issue (performance or otherwise).

In my scene, I have the Lerpz model loaded, and I've attached a component to him (a textured plane, in this case) which has its own animation - I'm assuming that the warning has something to do with this secondary 'child' animation but I don't understand what.

Thanks!

your answer can be found on this page:

http://unity3d.com/support/documentation/Manual/Modeling%20Optimized%20Characters.html

unity3d is warning you about not being able to optimize the character due to having multiple meshes and/or multiple animations in one object hierarchy.

if you can merge the lerpz character and the textured plane into one mesh with only one animation set, it sounds like you can benefit from the visibility culling that unity is trying to do.

if you won't have lots of characters and have a high frame rate still, you can probably ignore this warning.

and generally speaking, visibility culling is when you remove objects from the scene so that there is less to draw, thus increasing overall performance. it's usually refereed to in the rendering pipeline when you want to cull out objects the camera can't see, like off screen objects or the back side of a mesh.