Its a subscription site. You pay a monthly fee to be able to download the components/rubies/materials/styles and use them. Chris EDIT: Oh yes, they also seem to have an exchange site where you can upload a model and download other peoples models for free.

It depends how detailed you want the material to be. The maximum size I have made (or can be made without wasting your time and processor power) is 1024x1024 pixels. But this size really ought to be reserved for materials like a large sample of brick or stone that can be repeated without any obvious tiling...something like maybe 20 bricks wide by 50 bricks high. Other samples of textures can be much smaller. Most would be either 256x256 or 128x128; some can even be as small as 64x64. It is best to keep the sizes as multiples of 2 in this way, because they are more easily handled by the graphics processor....not a problem with one or two materials, but if you have dozens of them any small delays can multiply. In order to get some materials of a specific aspect ratio to tile seamlessly, you may not be able to have both dimensions conforming to these sizes, so just choose 1 side and let the other be whatever it is.

Do you want to be able t do realtime lighting or just static images? If its jsut static images: have a look at kerkythea and indigo. They are both very good render engines that can produce very high quality work. If you want real time i think your best bet would be lightup (i tihnk the site is down at the moment, not sure when it's going to be back up.) It's very good for giving an idea of how lighting will work in an interior and exterior. Bear in mind it is currently in beta.

You set up a scene with time in the morning then set up another one with time in the evening. See attached file (click on the Scene 2 tab) AnimatedShadows.skp