SSS (Subsurface Scattering)?

DigitalPictures

<div class="IPBDescription">Is this still being implemented?</div>I realize the game is still in an early stage, but are there still plans to include this? Remember it being talked about in alien structures, to get that glowing membrane feel to them from the inside. Will it also be implemented in the soldiers? I just wanted to see what's up with this and if it was still in the cards. SSS can really make the game characters come to life and would love to see it in this graphical style. Will the engine support it, even if UW decides to turn it off for NS2?

remi

Isn't SSS prohibitively expensive, in terms of processing time? I thought it was up there with raytracing... which totally will not be in this game.

jamin

SSS can be implemented in real time... So it's possible but I don't know what the team will be doing.

CXZman

Everything in a real time 3D engine is cheating. SSS is stupidly expensive because the physics around it is strange and complicated. No way near straight forward. But you can cheat it. Most pre rendered 3D apps now have a "translucent" channel on their materials that allow a color to shine from inside the model if the model receives light. Like any color channel, you can map this.

So what a realtime 3D engine could do is displaying that color as fast as possible. I guess...

Chris0132

SSS is like a prerendering thing, it gives nice effects yes but it's hideously complex and drags the render time down massively.

I really don't think you need it, a decent material system and a couple of overlaid textures for the alien buildings could give you a very nice effect with way less implementation time and rendering cost.

You probably wouldn't notice the difference anyway unless you knew what you're looking for, SSS is used to simulate light diffusing through a translucent substance, you aren't going to be looking for that while you're shooting aliens and dodging gas bombs.

Soylent_green

If there is an efficient fake SSS that works properly in a deferred renderer it can be applied to good effect on membrane-like things, like lerk wings; you will notice that even if you don't pay attention. Don't bother applying it to anything else, since you're in no way going to stop and notice how smooth the edge between light and dark on a fade claw is.

If you do it properly you're in seconds per frame territory.

Chris0132

<!--quoteo(post=1801176:date=Oct 10 2010, 05:02 PM:name=Soylent_green)--><div class='quotetop'>QUOTE (Soylent_green @ Oct 10 2010, 05:02 PM) <a href="index.php?act=findpost&pid=1801176"><{POST_SNAPBACK}></a></div><div class='quotemain'><!--quotec-->If there is an efficient fake SSS that works properly in a deferred renderer it can be applied to good effect on membrane-like things, like lerk wings; you will notice that even if you don't pay attention. Don't bother applying it to anything else, since you're in no way going to stop and notice how smooth the edge between light and dark on a fade claw is.

If you do it properly you're in seconds per frame territory.<!--QuoteEnd--></div><!--QuoteEEnd-->

You don't need subsurface scattering to do lerk wings, SSS is a volumetric thing, it takes into account actual thickness and bounces rays around inside objects.

You could do lerk wings by just making a material shader similar to self illumination except it's controlled by how much light is striking the back-face of the pixels the texture is applied to.

Much simpler than calculating light diffusing through the actual volume of the lerk wings.

I still doubt you'd notice it, lerks are going to be flying around or hiding in the shadows, you aren't going to see them standing in front of lights with their wings spread very much because lerks that do that are dead lerks.

Soylent_green

<!--quoteo(post=1801178:date=Oct 10 2010, 11:16 AM:name=Chris0132)--><div class='quotetop'>QUOTE (Chris0132 @ Oct 10 2010, 11:16 AM) <a href="index.php?act=findpost&pid=1801178"><{POST_SNAPBACK}></a></div><div class='quotemain'><!--quotec-->You don't need subsurface scattering to do lerk wings, SSS is a volumetric thing, it takes into account actual thickness and bounces rays around inside objects.<!--QuoteEnd--></div><!--QuoteEEnd-->

I know what SSS does and how it looks.

<!--quoteo(post=1801178:date=Oct 10 2010, 11:16 AM:name=Chris0132)--><div class='quotetop'>QUOTE (Chris0132 @ Oct 10 2010, 11:16 AM) <a href="index.php?act=findpost&pid=1801178"><{POST_SNAPBACK}></a></div><div class='quotemain'><!--quotec-->You could do lerk wings by just making a material shader similar to self illumination except it's controlled by how much light is striking the back-face of the pixels the texture is applied to.

Much simpler than calculating light diffusing through the actual volume of the lerk wings.<!--QuoteEnd--></div><!--QuoteEEnd-->

AKA one method of faking SSS.

<!--quoteo(post=1801178:date=Oct 10 2010, 11:16 AM:name=Chris0132)--><div class='quotetop'>QUOTE (Chris0132 @ Oct 10 2010, 11:16 AM) <a href="index.php?act=findpost&pid=1801178"><{POST_SNAPBACK}></a></div><div class='quotemain'><!--quotec-->I still doubt you'd notice it, lerks are going to be flying around or hiding in the shadows, you aren't going to see them standing in front of lights with their wings spread very much because lerks that do that are dead lerks.<!--QuoteEnd--></div><!--QuoteEEnd-->

Lerks are not played exclusively by the omniscient; sometimes they'll be flying out in the open through a well lit corridor because they strongly suspect there are no marines there and they don't have time to be careful. Sometimes they'll be forced to flee and get blocked by marines in a doorway. Sometimes they'll try to take an LA/LMG out with bite because they think they can get away with or they are cornered.

It's immediately obvious when you see it, unlike say, light filtering through a fade claw in a correct looking fashion.

Chris0132

Ehhh, I guess I don't agree with calling something 'fake SSS' when it doesn't work like SSS and doesn't create the same effect other than in a very specific circumstance.

If you are going to do special effects like that I think it'd be more worthwhile putting it in for structures, as they are more visible, move less, and you'll spend more time looking at them than you will lerks. A good structure glow effect would be more useful than lerk wing effects I think.

Turtle

Regardless of whatever you call it. For a game like NS, there's no need to put in SSS. It can be faked or just simply painted in by hand into the texture or texture channel. Otherwise, there are more visible effects to spend man hours on.

The lerk wing translucency can be handled via a simpler shader that samples lighting from above or below a lerk and adjust how much the wings glow.

DigitalPictures

<div align='center'><img src="http://www.thg.ru/technews/images/20060123-crytec2_crysis.jpg" border="0" class="linked-image" /></div>I was thinking something akin to that to make the characters less plastic toy dollish. I believe it is done with maps and it might not be true SSS. I'm not saying NS needs to resemble Crysis either, its a technology thing. Besides, why not put it in you always have the option to turn it off just like all other graphical settings. There's also no need to use normal maps, but they use them to make the environments look more real and detailed than they actually are. Anyways I remember either hearing about it in an interview or reading it from one of the staff. I think it had to do with the inside of the hive and they specifically mentioned sub surface scattering. They can come here and correct me if I am wrong, I was just curious about it. No need to debate it to death about weather it should or shouldn't. The question is: is it in,was it in at one point or was it not at all? Thanks.

Edit: I should also note that I'm more interested in this having to do with the Spark engine itself and not specifically NS2.

Soylent_green

<!--quoteo(post=1801182:date=Oct 10 2010, 11:43 AM:name=Chris0132)--><div class='quotetop'>QUOTE (Chris0132 @ Oct 10 2010, 11:43 AM) <a href="index.php?act=findpost&pid=1801182"><{POST_SNAPBACK}></a></div><div class='quotemain'><!--quotec-->Ehhh, I guess I don't agree with calling something 'fake SSS' when it doesn't work like SSS and doesn't create the same effect other than in a very specific circumstance.<!--QuoteEnd--></div><!--QuoteEEnd-->

Well, that's exactly how Crytek handled translucency on vegetation and they had no qualms about calling it a sub surface scattering approximation.

On faces they used texture space diffusion to fake SSS.

marks

Ignore Soylent_green, the guy is a massive, massive troll.

VonDoom

Yeah it would take ridiculous amounts of processing power to do proper SSS in real time. Most game engines who claim to do it are cutting corners one way or another :D