I have a scene and all my models are using vertex color and transparent vertex color but what I want to do now is make the same objects darker on different levels however if I change the color of the models shader it effects the models in other scenes… …now due to the fact that I have no lights in the scene and ambient render settings has no effect on vertex lit color models not sure what to do any ideas?..
You will need to use lights, as you can’t have model dependent color change without having distinct materials if you need the vertex colors.
Either that, or do something similar to what I did in Vertigo. Make the part of the texture that the darkening object uses as light as it will ever be, then add a second object which is transparent and unlit to surround the original object. Make the material a single, bright colour and then make it more and more transparent as your levels go on.
As the bright colour fades, the darker color shows through, giving the impression that your original object is darkening.
Adds another draw-call, but it works. I had to do this for the selected bricks in Vertigo due to the fact that I use the skinned mesh and bones thing to drive the objects in the scene - instantiate just wouldn’t have cut the mustard on the frame-rate.
cheers for the response guys not sure either approach will work however as im pushing the model limits on the iphone so adding more models is not a option and lights have no effect on vertix colored objects 
Vertex colored objects can indeed be lit by dynamic lights… you just need to turn on lighting in the shader you’re using.
ok will give it a try…cheers