Backface Culling

[joshbakr]

I'm wondering when "Backface Culling" will be implemented? Would this not reduce render times greatly?

I recall back when the previous Terragen started using Backface Culling, it was a major step forward in my opinion.

For those not familiar with this term here's a link to wikipedia .http://en.wikipedia.org/wiki/Hidden_surface_determination

[Oshyan]

Backface culling is already in use. That's why you can see through the terrain and get odd effects when rendering from underneath the terrain. Without it you would see the underside of the terrain.

What you're probably thinking of is depth-based occlusion culling, which avoids rendering of parts of the scene that will later be covered up by other parts. TG2 also has a form of depth-based culling, but due to the complex nature of displacement-based terrain and some still-pending optimizations, it doesn't always cull at maximum efficiency. Future enhancements will be implemented to this which should allow for better culling, but there may still be imperfect culling of the scene in some/many cases. It will at least be an improvement.

- Oshyan

[sjefen]

This depth-based culling thing. Is this fixed or improved for the final release?

- Terje

[Oshyan]

I don't think any major improvements have been made in this area specifically, though overall render time has improved since the original discussion from various other minor optimizations.

- Oshyan

[rcallicotte]

Good information to know.  Thanks Oshyan.

[Mohawk20]

I still have issues with this, because I have a very high-res image of an island, but first all the water is rendered, and then the island, more than doubling the render time.
Is this better in TG3? Or are there workarounds now? I do my test renders with the lake disabled, but I can't do that for final render...

[Oshyan]

This is not changed for TG3. It's recommended for now that you mask any large areas of water if they will be covered significantly by terrain. We do have future plans to address some of these issues as well.

- Oshyan

[Matt]

This is relevant, particularly the part about "sorting bias":

http://www.planetside.co.uk/forums/index.php/topic,16440.msg161033.html#msg161033

Matt