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wacom
01-10-2005, 09:58 AM
Here is a link I found just last night to Thrij's fake SSS technique. It's quite good, and I wouldn't have found it had it not happend by some accidental browsing. Download the example and try and expand on it- looks cool...

I think if there were some weight maps added and incedent angle controls we might get even closer...

http://vbulletin.newtek.com/showthread.php?p=241143&highlight=SSS#post241143

wacom
01-10-2005, 11:31 AM
Here are a few more tests. I've added an inverted gradient Diffuse channel that is coupled with a subtractive gradient based on the light null distance. This seems to help make the materal stand out better and behave when it's NOT supposed to be doing SSS.

I also added an slight camera incedent angle gain gradient on top of the null distance one that is tempered by another subractive distance to the light null gradeint. This gives the effect of a little more "back light glow" or bounce'n light.

I also coupled the point light with an area light to cast some shadows...and exluded any objects that needed to be giving light and still casting shadows (hence the candle like thingy).

Haven't even played with weightmaps and gradients yet to control where the effect is greatest (IE earlobes...fatty places with no bones that are "thin enough".

wacom
01-10-2005, 11:46 AM
Here is a scene with this surface using my version of Thrij's technique. It runs fast in FPrime...but you'll have to turn off a few things go get it cook'n in regular LW. Turn off the refraction and refraction bluring for starters.

The scene was made in FPrime with BG radiosity turned ON...but you don't need all of that to get going.

If you find something new please share it here or in the other thread:

http://vbulletin.newtek.com/showthr...=SSS#post241143

The attached file only contains the "costly" rendering scene. Try the second one ( Fake SSS example_b.zip) if you're using the native LW renderer and not FPrime. There is a simpler scene included in that file.

chikega
01-10-2005, 08:33 PM
Very cool stuff ... I certainly will be checking this out after all the SSS studies I've done with and G2 (http://www.3ddmd.com/test_renders.htm) and messiah (http://www.cgtalk.com/showthread.php?t=115932&highlight=chikega) . Looks like it would be much faster than OGO_Hikari for most situations as well. Thanks for the heads up! :)

wacom
01-11-2005, 12:49 AM
Here is an updated file with a simpler scene file included. The one I have above was with the settings I used to render the images above in FPrime (with BG radiosity). I forgot to turn off some settings I was using mainly to test backlit shadow effects etc. You don't lose much SSS detail in the objects in the simple one, and it renders in 6 seconds on a Dell 8200 1.75Ghz machine in native LW!

Here is the updated:

ThriJ
01-12-2005, 10:12 PM
I was just browsing along yesterday and I found a thread called Fake SSS solution by Thrij. I thought, ”hey ThriJ has a SSS solution. I also have a solution. Hey wait a second, I’m ThriJ!”

I thought about making a thread on the effect, but I would never have gotten around to it. So, thanks wacom!

I must say I did not expect people to be so interested in my technique. I guess that makes me stupid, but wacom thinks I’m a genius, so I’m currently confused… which could say something in of it’s self? :rolleyes:

Anyway, those are interesting tests by wacom. I’ve been playing with them a little. I have a few test renders below. The best results come from applying the gradient to the color channel, which by the way is how I got the rich glow effect with my organic thing and candles. I have an Idea for enhancing the illusion; I’ll release some more images if it works like I want it to.

wacom
01-12-2005, 11:47 PM
OK...so maybe I'm a little too excited about things like this. Those last few posts look super swank ThriJ. I'll have to play around more with a color gradient on top of it all. It adds that extra bit that makes it seem like the SSS is in the right places. The effect of the SSS getting more pronouced as it pass through more material is what it seems to be simulating better.

I think I'll go look at a candle now...and not blink for a day or so...

peteb
01-17-2005, 05:09 PM
I'm just trying to get my head round this stuff. I came to the same conclusion as you guys in attaching a null to a light to increase the luminosity channel. Didn't know how surface thickness works so haven't touched that yet but I see in your scene you've got that on top. I was thinking if you add a weight map set to alpha on top would this allow you to direct where you want the luminosity to appear?
I've been trying to think of a way of tying in a luminosity map with the distance of the light as I think this would be the most realistic way to do it. But I haven't got a clue how you do it. The only way I can think of is by using expressions, I had a quick look but they really are beyond my very limited knowledge. You'd also want the area where the luminosity was to turn a red colour, well if you were trying to do skin and again I haven't got a clue how to do that.
Do others think this might be a way to go. I can imagine if you can assign the image maps to work with the light distance you'd get some really nice precise effects. Or am I well off the mark?

ThriJ
01-19-2005, 10:08 PM
Interesting ideas peteb. I have got the best results from UV maps instead of weight maps. Applying the gradient to the color channel is one of the best ways to get the skin color shift effect.



Because the effect is a fake anything below the surface or inside the object does not appear like in real SSS.

In my latest experiments I tried a few ways to get around that problem by:

Copying and pasting the polygons, flipping the new polys and giving them a new surface with the same settings, and then giving the original surface a bit of transparency.

You can’t see through the object, but anything inside would appear as a dark mass if viewed from an angle with the light behind. It looks exactly like a real translucent SSS object, but the downside is that it will not work right if the object has a complex shape that has polys in front of polys.

Below are some of the same Images and an animation that I just posted on the other thread.

peteb
01-20-2005, 05:16 AM
Yeah I had that thought but like you say it's becomes to much for complex objects. Some really nice result you're getting there.
I managed to create a texture that would turn red when a light got really close to it by applying a texture. I done this by applying a gradient set to distance to object and then a red colour texture with an alpha. I then added this same sort of settings to the Luminosity and translucent settings and got some decent results. The only prob is that the light reacted across the whole map and not just to the pinpoint area of the light. Maybe I could solve this by adding another gradient set to light incidence but I'm not sure how this would effect it.
I think weight maps will work for most of your every day stuff like candles and objects that have an overall sss to them. But I was thinking along the lines of things like hands where you really see the effect in areas like the webbing between fingers. By having an image map you could get areas like veins or thicker skin.

I'm so new to gradients that I don't think I have the expertise to get the job done but i guess practice makes perfect. I just wish I had a better grasp on what surface thickness does as I haven't got a clue how it works with relevance to the gradient?


Peter

Thunderb
01-29-2005, 10:27 AM
Hey guys I love the technique, thanks for the idea! Lots to play around with, its quite good for skin and really fast!

Captain Obvious
02-23-2005, 05:26 AM
Great technique! But would it be possible to add shadow colouration? See this:

peteb
02-23-2005, 06:00 AM
You'd have to fake it with lights I guess

ThriJ
02-23-2005, 01:26 PM
That is incredible looking skin Thunderb!




Great technique! But would it be possible to add shadow colouration?

Could you post that scene Captain Obvious? There are a few different ways to apply the color. The best is to just apply shadow color.




I just wish I had a better grasp on what surface thickness does as I haven't got a clue how it works with relevance to the gradient?

Apparently there is a good deal of people who are confused with the Surface Thickness gradient. I was a bit confused myself when it was first added.

Surface Thickness uses Ray Tracing, so you canít see the results in viper. I added an image that should show what its doing.

Captain Obvious
02-23-2005, 03:49 PM
So, uh, how does one use surface thickness? I've been playing around with it, but regardless of what I do with it, it doesn't have any effect what-so-ever. Oh, and how does one add shadow colouration?

GregMalick
02-23-2005, 04:57 PM
Thunderb & ThriJ -

It would be incredible :D if you could take one of the free LW objects (like girl.lwo) and use this method for some SSS skin - and post the object in this thread. Any low poly head would actually do...

Then we (less than genius) wavers could pick it apart and possibly even start using the technique. All I know is that when I looked at Thunderb's skin effect picture - I was just bewildered as to how he used this technique to get that great effect.

Thunderb
02-23-2005, 07:04 PM
I have a zip file ready for inspection if anyone wants to check it out. Its 2.5 megs zip file, I never usually give out stuff or do big posts so how can I upload that much?

Castius
02-23-2005, 08:56 PM
I should be able to host it. I don't have tons of bandwith a month so i'll just keep an eye on it.

toby
02-24-2005, 10:57 AM
Surface thickness basics:

http://vbulletin.newtek.com/showthread.php?t=4864&highlight=surface+thickness

ThriJ
02-25-2005, 01:50 PM
So, uh, how does one use surface thickness? I've been playing around with it, but regardless of what I do with it, it doesn't have any effect what-so-ever.

Oh, I forgot to mention that you also have to turn on double-sided polygons in Surface Editor, how stupid of me.

The exceptional link provided by toby should clear any further confusion with surface thickness.


and how does one add shadow colouration?

I added an Image to show Shadow Color. I copied the light to have more then one color.



Thunderb & ThriJ -

It would be incredible :D if you could take one of the free LW objects (like girl.lwo) and use this method for some SSS skin - and post the object in this thread. Any low poly head would actually do...

I kind of wish I had saved the experiment scene with the Inside LightWave girl, but it appears that Thunderb has got you covered.



I have a zip file ready for inspection if anyone wants to check it out. Its 2.5 megs zip file

Heck, Thunderb what did you do to make the scene that big? :eek:

DragonFist
02-26-2005, 10:26 PM
Hey, ThunderB. I'm working on getting as perfect skin as I can and would love to see how you did that. If you can't do the entire scene file, can you just attach the surface file for us to look at?

antwik-2
02-28-2005, 07:09 AM
That looks cool, but what does the "distance to object" parameter do on the translucency channel?
can some one explain that.

And for the head, dont you need thickness to be able to get the fake SSS?
a open polygon mesh would not show the effect

ThriJ
02-28-2005, 09:41 AM
Hey first of all I would like to congratulate wacom for developing the incredible sketch effect:
http://vbulletin.newtek.com/showthread.php?t=33682 That’s wild wacom!





That looks cool, but what does the "distance to object" parameter do on the translucency channel?
can some one explain that.

And for the head, dont you need thickness to be able to get the fake SSS?
a open polygon mesh would not show the effect

The closer the light, the more vivid the effect. Actually I do not apply the gradient to the translucency at all, but it is good to turn translucency up to 100% for correct shadows. Thickness has nothing to do with my technique, so you can apply it to a flat plane if you wanted too. :)



Hey, ThunderB. I'm working on getting as perfect skin as I can and would love to see how you did that. If you can't do the entire scene file, can you just attach the surface file for us to look at?

I believe that Thunderb is using a UV image map on top of the SSS effect. Unfortunately that would make it difficult to just save the surface.

Thunderb
02-28-2005, 11:16 AM
Ok Kiddies, heres is the test scene with surface. Now it is an approximation of what I use. The model needs texture maps for the best look but that made the file too big. So have a play copy paste the setting to your own models, play around with the gradient settings and light/null distance!! use Translucency maps or fake it with Illumination maps! Just play around with the file, I recommend Fprime for this because you need GI on I'm afraid. Like I said it works for me, maybe not for other. :D

peteb
03-01-2005, 04:12 PM
Hey thanks for that thunderb. Just a couple of questions. How comes you had the null set so far away from the light that was being used for the luminosity and how comes you had a incidence angle set for reflection, I thought that would only be used for a Fresnel effect?

Pete B

Thunderb
03-01-2005, 06:22 PM
Hey Pete,

the fresnal effect seems to work well on some head meshes, it give the skin a kind of fluffly feel when it reflects ever so slightly on the edge. Not sure about the null question, I just mess around until I get an image that looks good basically, just mess around with the settings. You need good image maps really for skin I feel, but the light setup is great for skin and I use HDRI maps supplied by DOSCH DESIGN. Have a play and improvise, Lighwtave really needs a good SSS shader, something better than G2!! Maybe if G2 and Fprime were integrated we would all be ok!!! :D

DragonFist
03-02-2005, 12:37 AM
Not sure how to attach pictures, but I'll try. If it succeeds, it is my attempt at getting skin right from your example. There is more for me to do I think other than texture maps.

On a side note, What exactly are "HDRI maps"? I've seen talk of it and did some searches on it but haven't found what they are.

peteb
03-02-2005, 03:44 AM
Not sure what HDRI maps are. HDRI stand for High Dynamic Range Image which is used for lighting scenes in radiosity because it can retain information higher then 255 255 255. It does this by taking a picture of a scene at different exposures and combining them together. You can get software that does this like HDR shop.

I was thinking about SSS again last night and was wondering if you'd get better results from using the diffuse channel. Thinking about skin and how it reacts to light. You get more saturation at the terminator between light and shadow. So what if you set a white base value for layer one in diffuse. Then your diffuse map on layer 2 and then on layer 3 a gradient set to alpha so it takes out parts of the diffuse map below. You could set it to incidence angle for the light and have it so it reveals more of the bottom (white) layer on the edge of the face thus creating more saturation on the edge.

The other thing I reckon could work is the brdf filter. I haven't played with this properly yet but thingking about it logically this seems like it could work.

This is all theory and probably rubbish but I'll try it out at some point.

Pete B

ThriJ
06-29-2005, 07:28 PM
If anybody is interested I have finished upgrading my site. My website is finally fully up and running.


http://www.geocities.com/the3dentsanimation/