Vray Skin 2 - Tips

[MikeANash]

Thought I would post up some Vraysss2 tips, along with anyone else willing to share.

I will just explain my own "Artistic" understanding of what the parameters do.

Prepass rate - Increases quality of sub-surface scattering. Leave at -1-0 for tweaking and 0-2 depending on final render size.

Scale - Leave at around 1 If using real world scale.

Overall color -
1737

Diffuse amount - Will apply a diffuse value overwriting your sss effects based on how much your diffuse value is set to. Useful for makeup/hair.

Sub Surface color - Linked to your SSS Col.

SSS Col -
Example:
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Scatter Color - The more you darken, the less apparent your sss effects will be. You can also use it with a texture map like the example below.
Example:
1710

Trace Reflections - Turn it on for some nice reflections. It will slow down render times.

Single Scatter - Change it to simple and leave the rest on default, apart from other settings I will list below.

Front Lighting - Leave it on. This enables your front sss scattering.

Back Lighting - This will slow down your render times a little. All it does is add that nice sss glow effects in the ears and fingers. Usually leave it off if you are not tweaking your back scattering.

Scatter Gi - This one is a killer to your render times. Only turn it on for final renders.

Whenever I have it off, I will also turn off indirect illumination/GI environment. Leaving indirect illumination on will tell it to bounce light just off the top surfaces of your skin instead of absorbing the light like real skin does. I may be wrong tho :/


Now onto a little more confusing area.
Since vraysss2 is lacking in good reflections and Spec controls you need to use it along with Shellac material.
So all that means is you are blending vray sss effects with a diffuse material to leach the extra reflection controls from.
You need to insert VrayMtl into your Shellac material slot and set your diffuse to black and apply your spec map.

My results may not be as good as others, but hopefully it will help people to get started with using it.
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Feel free to post your tips or crit any of the above info.

3Dsmax mat attached below.

[adamlewis]

Thanks for the tips, Mike. With regards to VRayBlendMtl, have you experimented with the additive shellac mode? As the name of the setting implies, instead of blending the materials in the node together, it will add the coat layers on top of the base. This has the advantage of allowing you to derive the reflections from the VRayMtl while omitting other properties such as the diffuse coloring. From my limited experiments with it it seems to work fine, but I am relatively new to Vray so I may be missing something.

[MikeANash]

Double Post

[MikeANash]

Hey Adam

Your right, I've been looking for something like this,thanks alot :thumbsup:

[Manuel Poehlau]

Nice tests Mike. The sss seems a little bit strong.
I think it´s a good idea to start a vray skin thread,since there is not so much info about it out there.
I also use the shellac mode to blend the vraymatl reflection with the sss2 shader, seems to work fine. For a clean skin ( i mean,no dirt,no make up,no hair etc) I don´t want to have any diffuse value mixed in.
Looking forward to see more results :thumbsup:

[collings]

cool Mike thanks for sharing :)

[MikeANash]

Cheers guys,
I've updated the above info/shader to work a little better.

[tiktok]

wow! awesome. thanks for the tips! your results look fantastic. going to try to port this over to vray for maya ;P

[Ganjica]

Great idea! I spent the whole day yesterday to tweak the specular with sss2, and at the end I made a 2nd light rig just for the specular since I was not happy with the results. I thought it was just me having troubles with lack of settings for the specular and reflections.
Using the shellac is a way more powerful and ant time saving!!

[Ganjica]

One more thing I noticed but I don't know if coming just form my wrrng settings, is that GI seems to kill a good amount of the scatter effect. Do you guys use GI when you render with vray?

[adamlewis]

Ganjica, if you're using GI make sure you turn on "Scatter GI" in the VraySSS2 properties (at least for final renders; the setting is very expensive). Without that setting on, indirect rays will be treated as if they were hitting a plain old diffuse surface. I'd also recommend turning off or at least severely limiting the "Generate GI" setting under object properties, as it creates a rather undesirable look with SSS materials under most circumstances.

[Ganjica]

AAAaaaaaarrrrggghhhh! That's why every time I was tweaking the settings without the GI the shader was looking good, and then it was going to act as a normal blinn shader, now i got it! Thanks a milllllion!!

[kpamir]

Great thread Mike.

I am a new Vray user and trying to get a handle on the SSS shader.

I am trying to figure out how to have SSS and no SSS on the same model using the Vray SSS2 shader.

I have plugged in a map into the diffuse color slot of the shader but that is giving me weird results. I basically want the bones on the models back, tail and elbows to have little to no SSS and the skin to have some SSS effect.

In MR I would a map into the overall diffuse slot (if i remember correctly) for anything I didn't want to have and SSS. I assume it would work the same for Vray but maybe I am doing something wrong.

I linked an example below.

http://lh5.ggpht.com/_nyXPWzJhZG4/TR_jKYeUXQI/AAAAAAAAA78/51iQ9aMbzrY/s800/sss.jpg

Any help would be appreciated.

[gjpetch]

kpamir, Use a black and white map in the sss2 "Diffuse amount" to control the amount of diffuse showing through. Black means zero diffuse and 100% SSS, white means 100% diffuse with no SSS.
Just curious, when you guys are talking about a lack of settings in the sss2 specular/reflection, what settings are you missing?

[kpamir]

Thanks I had the map set up in the opposite way. White for SSS black for no SSS.

I was wondering if someone could post up an example screenshot of the shellac/vray blend material setup. It would be a huge help.

[keraj37]

Well, I dont know why u guys use blending material. For me in vray 2.0 reflections work fine.

[harford]

Because the stock SSS2 reflections don't offer much control. Greater realism and effects can be achieved by combining it with a regular vray shader in a shellac node.

However rendertime does go up quite considerably.

[Tomaya]

Thanks for sharing mike , vray sss2 is a bit tricky but it works well ... it helps ...:thumbsup:

[rasmusW]

thanks for starting this thread mike. surely a lot of stuff to dig into for a vray noob, like me...
hope to be able to contribute to this some day..:)

-r

[kpamir]

http://2.bp.blogspot.com/-4dx7bJdcQsg/TVhql_jHTaI/AAAAAAAAA8s/eiu6qphSATo/s1600/Bust_test.jpg

Hey guys

I hope I am not intruding on your thread with this post Mike.

Here is a skin shader and model I am currently working on. I would love some feedback regarding the skin and anything else to be honest. But definitely the skin.

Thanks.

KP.

[pionier]

nice topic Mike,

I did not use shellac node before, looks like it does the job quite nice. I will have to play with it more. also, i didn't switch off generate gi for objects with sss, thank for that info

here you can see my few test of skin shader, I used vray sss2 and vray mtl blend with vrayblend material. I used model and textures from this tutorial: http://www.ten24.info/index.php/shop/character-training/Tutorial-33/

http://img641.imageshack.us/img641/3351/skinshader02b.jpg
http://img840.imageshack.us/img840/6387/skinshader04a.jpg

and this is what I get so far from mr skin shader:

http://img577.imageshack.us/img577/3299/benskinmr.jpg

I'm still not happy with the result of vray sss2, how do you guys 'translate' names of epidermal/sub dermal maps to vray shader?

also, as far as I know the sub dermal and scatter maps should be blurry and epidermal should have less blur apply to it.

btw, it's my first post here - hi everybody :)

thanks,
Peter

[kenshiro]

Thanks a lot MikeANash for tips! really usefull! :)

[pionier]

today I spend some time with vray shader and this is what I have so far:

http://img145.imageshack.us/img145/3127/skij5.jpg

what do you think guys?
imo, I still don't know how to make it more 'skin'/'meat' look :|

[thatbumzzz]

Thanks for all the awesome SSS info. I tried some of these but unfortunately I had some issues. I'm still quite new at Max so I apologize in advance.

I had a render I did which was an import from Daz Studio which looked fine but I wanted to try the FastSSS2. The skin definitely looked much better but for one the render took 4 hours instead of 2. Is that normal? There were white spots all over the shiny parts of the skin specially at the edges of the body, kind of like when subdivisions on lights are too low producing spotty shadows except white in this case on the skin. Lastly the skin was much darker(made for a nice tan lol) even though I made all 3 color boxes very light pink in the SSS.

I didnt try the shellac mentioned so maybe that was the problem, but Im afraid I dont know how to take the FastSSS2 and make it shellac. Also for the diffuse people mention do I just use a completely grey square texture the size of the skin texture if I want it 50% shiny skin?

Again my appologies for my noobishness. Ive watched many vids and read several tutorials but it is still quite overwhelming :)

[adamlewis]

Looks pretty good, Piotr. Did you use photo sources for your texture? It looks like there is a lot of lighting and shading information baked into the texture, which is fighting with the shading and lighting in the actual render. I find you have to be very careful with your saturation and brightness values in the texture, as it is really easy to overdo things - and this is especially the case if you are using a photo. Ideally, try to keep those values fairly linear across the texture, and only vary where it would be appropriate, such as areas with heavier pigmentation; the lips, freckles, liver spots etc. This will help a lot in giving the skin a fresh, natural appearance.

Zeus: If you are new to Max and Vray I wouldn't worry so much about learning the FastSSS2 shader as learning Vray and Max more generally. The FastSSS2 shader is really quite simple to work with, but will be frustrating if you're not yet comfortable with the core concepts of Vray, things like the image sampler, GI system, color mapping, working in linear etc. Once you have those things figured out, FastSSS2 will be easy for you to work with.

[thatbumzzz]

Zeus: If you are new to Max and Vray I wouldn't worry so much about learning the FastSSS2 shader as learning Vray and Max more generally. The FastSSS2 shader is really quite simple to work with, but will be frustrating if you're not yet comfortable with the core concepts of Vray, things like the image sampler, GI system, color mapping, working in linear etc. Once you have those things figured out, FastSSS2 will be easy for you to work with.

Thanks for the feedback, but I'm afraid I dont have access to any classes where im currently living and recently unemployed so I need to avoid spending on online classes. Do you have any links to where I can watch newb friendly free tutorials on the subjects you mentioned? Most tutorials I watch always assume you know a bunch of stuff, but when I look up that stuff they assume I know the stuff I tried to look up in teh first place lol. Really the only problem Im having with FastSSS2 is the splotchy white at the edge of my models skin.

[pionier]

Adam, thanks for you feedback - yes I do use some photo texture for textures, I knowed is a not a good way to go, I will have to re-create all textures and try it again. I also didn't notice your topic with skin shader study before I post my images here :banghead: and I probably will start my own 'study' topic as well, sorry for mess up your topic Mike.

peter.

[thatbumzzz]

I figured out it is the trace reflections that causes the splotchy white edges. But how can I keep the nice white glow from trace reflections on and not get the splotchy white edges?

Here is the image, shes a she hulk type amazon:

http://www.renderosity.com/mod/forumpro/media/folder_10/file_467530.jpg

[adamlewis]

Looks like you simply don't have enough light samples. Either increase the reflection samples under the SSS2 options, or use more aggressive global image sampling settings. The 'Universal Vray' settings are a good starting point, you can read about it here: http://www.spot3d.com/vray/help/150SP1/tutorials_unisettings.htm

And if you're serious about learning Vray, this book here has virtually everything you will ever need to know about it: http://www.francescolegrenzi.com/blog/static.php?page=vray_guide_eng

It's not free, but absolutely worth it if you really want to learn Vray.

[thatbumzzz]

Looks like you simply don't have enough light samples. Either increase the reflection samples under the SSS2 options, or use more aggressive global image sampling settings. The 'Universal Vray' settings are a good starting point, you can read about it here: http://www.spot3d.com/vray/help/150SP1/tutorials_unisettings.htm

And if you're serious about learning Vray, this book here has virtually everything you will ever need to know about it: http://www.francescolegrenzi.com/blog/static.php?page=vray_guide_eng

It's not free, but absolutely worth it if you really want to learn Vray.

Thanks again for the tips and info! I found another way to remove the white spots, I had reflectione/refraction override at 5 under environment(from one of the various render settings I tried but forgot to turn off). When I set it to 1 I still kept a bit of the shine, but at 2.5 it became spotty. Is there another way to do the reflection? When I turn off the reflection/refraction override the shine goes away completely unfortunately.

Im afraid I couldnt figure out how to increase the reflection samples as you suggested or fiogure out how to use more aggressive image sampling settings. Its definitely reflection related though. I might just stick with it at reflection/refraction environment at 1 since it looks quite nice but not as nice a glow(though spotty) as it was at 5. Unless you have a suggestion :)

[C-R]

Are you guys always testing your skinshader in the final resolution and with the final camera position? Seems like the scattering of the skinshader is somehow related to the size of the rendering :(

[adamlewis]

Depending on the size of your SSS illumination map, Vray will normally try to interpolate it with regular diffuse shading if the samples aren't adequate enough, and consequently decreasing the overall SSS effect. You can disable that by setting Prepass Blur very low (like .1). The downside is you might not have enough samples for your SSS, giving you a splotchy look. You can solve that by increasing the Prepass Rate, which effectively doubles the size of the illumination map each time you increase it. A setting of 1 generally works quite well for most situations, and 2 will give you extremely good quality at the expense of huge render times (and possibly running out of memory). Also, if you're using GI in your render, enabling Scatter GI will also increase the quality of the illumination map. I usually use Prepass Rate 1, Prepass Blur .1, and GI Scatter enabled and that gives very good quality and predictable results while still being reasonably quick to render.

[kpamir]

Thanks for that tip Adam.

I was wondering if most of you guys use Bump maps or Normal maps for high frequency details?

I use normal maps and they dont seem to bring out all the details that they should with the SSS shader. Maybe I am doing something wrong, or maybe its a lost cause.

Just wondering what you guys use, and what is more effective.

[nfuchs]

I'm using displacement + bump maps or nothing just the highres model decimated.