Maximum scene sizes - GPU Ram

[3dfish]

Hi everybody.
I'm new on this forum as well as on GPU rendering. I keep reading that the scene size is limited by the RAM on the GPU. I get that the whole scene has to fit on the GPU RAM so that the render engine has access to it.
What I'm left wondering, is what "size" does it take into account?
For instance, in order to set up my scene accordingly to the GPU limits, do I have to add the "weight" in MB of all my textures to the scene weight in MB, along to any other assets I may be using? Or is it more complicated
For instance, if I have a (totally random even numbers) card with 2048MB of RAM, does it mean I could work with a 1024GB scene with four textures that weight 256MB each on my hard drive ?(again, just an easy to calculate number, not that my textures weight that!)

Thanks for your help!

[mib2berlin]

Hi, more or less yes.
Textures has to be expanded in the GPU Ram (VRam) so 4 uncompressed pictures.
Don´t forget the geometry of your mesh.
Currently you can have up to 64 image textures, 32 float textures, and 4 HDRI RGBA textures and 4 HDRI greyscale textures for Fermi cards.
Kepler cards texture limit is higher, 144 image textures iirc.
But you can see what artists can do with these limits in the gallery.
You can use one image multiple times it is only one time in VRam or you use Octane materials like this:

http://render.otoy.com/forum/viewtopic.php?f=5&t=33423

Cheers, mib.

[3dfish]

Okay, thanks!
Is there some kind of way to check the total size from, say, 3ds max?