I have read some posts about memory management, and am still left with a few questions - maybe someone can help. Currently, I am aiming at higher-end harware that supports pixel shaders, and a world created from high-poly count models.

Models:

When a model leaves the clip distance, is it still loaded in memory? Would you need to purge it to free that memory again? If the model is purged when it is outside of the clip distance, and you move so that it is once again in the clip distance, is it reloaded?

If a model is reduced in polycount at a certain LOD distance, is the older higher count model purged?

What are the limitations on level size in this scenario. If you move in one direction, and the models are purged from memory as they leave the clip distance, would you theoretically be able to continue forever?

Textures, Video Memory, System Memory:

What is the relationship? Is there a limit to the number of textures you can use, and if so how is this determined. If a texture associated with a model is purged, are all of these resouces available again?

I guess what I am getting at is... I have a room built with high res textures, and detailed models, with shaders and the works. It is an indoor scenario, so the clip distance is not too distant, as I build this out to a large level, what limitations will I run into in terms of memory. I would rather avoid going back and reducing texture sizes, and/or reworking models to have a lower poly count.

I understand LOD, and plan on implemeting this. I also have read alot of posts about optimal texture resolution, and I understand the concept that you make every attempt to conserve on poly count and texture sizes.

As things progress, I am sure I will learn alot about this, and I will be conducting some tests, but I was curious if other users had any insight that might help me on my quest.