Skin in Iray vs Cycles vs ???
j cade
Posts: 2,310
Alright, strap in... (or skim). So there have been a lot of discussions in the past about comparing render engines, which one "looks better" "is easier" Now, personally, I think a lot of these things come down to personal preference, But one thing I also noticed was that most of the render engine comparisons floating around out there don't focus on skin, which is what most Daz folks are rendering, making them extra unhelpful. And of the more Daz specific comparisons they tend to have complletely different lighting setups from engine to engine, again making a clear comparison of how the materials compare impossible
To that end, I have set up a scene with the goal of 1, being a decent setup for showing off skin, and 2 produce nigh identical results in different render engines. Its piteously simple, a HDRI and diffuse white plane. Its not the most beautiful setup ever conceived, but it does a decent job showing off skin, and since the only real light is an HDRI, there's not a lot of differences in lighting to worry about in different render engines. This is one part comparison and one part request to the community
For my Comparison: Iray vs Blender's Cycles
(click the image to go to the larger one in my gallery)
Render Time: Iray 2 Hrs. Cycles 2.5 hrs (would be less if I had used the same hair as Iray)
render time notes: Well for one thing I'm not running a fancy rig here. I'm working on a pretty underpowered laptop with 8GB of normal memory and a 2GB GPU that conks out on most things, and runs hot on the rest. So 2 hours for a render is pretty quick as far as I'm concerned. Comparing Cycles vs Iray: blender prefers renders blocks, whereas Iray renders the whole image progressively. This has some benefits for blender in terms of memory, but it does mean you have to set samples to the amount you want before hand, if you set it to low, you get grain and theres not much you can do, too high, and the render takes longer than necessary. Also you can't pause blender renders which saddens me. On the other hand you can totally edit your scene while the rendering's going on, not that I find that particularly useful, but you can.
Material Setup Time and Ease: No exact times but Iray is the definite winner for this this one.
Notes: It takes me 2 minutes to set up skin in Iray at this point: I have 2 material presets, I apply them and maybe do a bit of extra tweaking on the eyes. In Cycles defense, I was basically creating my own skin shader setup for this one, and next time I can use it for a basis and skin setup should be in the 5-10 minute range. Less in blenders defense, you may have noticed the phrase "creating my own skin shader" You can find different and some very nice shader setups out there, but nothing is really out there that was created with the daz figures in mind. You will have to tweak, If you don't like tweaking you will not enjoy cycles. You also cannot edit multiple material zones at once, there are workarounds, but they can be a bit odd.
The advantage of cycles is that tweakability, if you like obsessive control over every setting, and the ability to go "I want to add this" > add a few nodes and get the added effect you are looking for. Add some tiling bump that's not tied to the mapping so its completely even across all surfaces? Easy. Quickly mask out the eyebrows from the SSS? Done, and with no extra maps taking up memory either.
Skin appearance comparison: well, they're pretty close, non? that was part of the goal for me initially. I like my Iray skin settings and wanted to see if I could get something close in cycles. I still like Iray a little better, in particular, I think Iray does better with crevasses and where a mesh intersects itself like the eyelids, which got some weird brightening in cycles. I also like Iray's front scattering: the shadow lines on the neck soften up a bit better in Iray, whereas in cycles I had issues with getting jagged shadows. The advantage, I imagine, of Irays more physically volumetric approach. On the other hand, since cycles SSS method doesn't use the physical volumetric settings it was easier to set up properly with the genesis' less than physically perfect eyes and have the scelera blend with the cornea. The bounce light in Blender is a bit stronger. Its particularly noticeable on the underside of the chin, although its noticeable in the sphere too actually. Whether this is a result of Iray losing a bit to much energy, Cycles not losing enough, or something else, I couldn't tell you.
Other: So you may have noticed one tiny difference between the 2 renders. Blender's hair. I love it. I just couldn't help myself, the whole point of this test was mostly because I wanted to see if I could get cycles skin I liked as much as Iray skin, because right now there isn't a equivalent to cycles and blender's hair for Iray. Yes, I know there are Garibaldi and LAMH but there's 70000 strands on that head, and I've done other hair styles that needed more. Trying to convert that many to something renderable in Iray would send my computer to a crashing halt. Additionally blender's setup and all those lovely nodes make it easy to shade the hair both by the strand and root to tip, meaning I can have all the individual strands different colors, and make the roots darker across the board or make the roots slightly transparent to blend better with the scalp. AFAIK this is straight up not doable with mesh conversions
Also some people might argue that blender and "easy to use" should never go together, but, man, blender's hair system is super easy to use, yes, in my opinion, easier than either of the studio options. I can usually setup a new hairstyle in under 30 minutes, which, in case you're wondering, is pretty ridiculously fast for creating an entire new hairstyle
Now for the ??? and community request, I would love for this comparison to be more than just Iray and Cycles, but those are the only renderers I have and am comfortable with.
I would love for some folks who are good with Octane or Luxrender or any other renderer to render this scene to the best of their abilities in their engine of choice.
The scene file will contain everything you need for the lighting (a supplied hdri and a diffuse white plane) and Genesis 3 with Victoria's textures and morphs. Simply add a short hair that leaves the ears visible (I used Qain Hair). Keep the textures mostly the same (I will admit for my renders I changed the sclera textures to Olympia's because I hate V7s sclera textures , but don't, say, use an entire different texture set) and set up the materials for the render engine of your choice. *edit I also used my iris depth morphs, linked in my signiture under communism, they are now not automatically loaded so the scene file won't throw errors at you
Feel free to show off the advantages of your engine of choice (like I did with Blender's fantastic hair); sell it to us a bit. What are the advantages of your method? Also don't feel obligated to match as closely as I ended up matching my Cycles Shader setup to Iray, thats more an effect of both images being made by the same person than anything else.
Why 32 bit for the comparison Image? well I've found that hdr strength output varies so the easiest way to make sure the lighting is completely identical is to render out a exr or hdr, and in photoshop place the new render directly over top the Iray render and adjust the exposure until the sphere is as close to completely black as possible, this ensures the closest possible lighting match. Honestly Its probably a bit overkill, But I'm a firm believer in overdoing.
Sorry for the wall of text
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Comments
For us Carrara folks we cant use Gen3 so I will see if I can get a Gen 2 version sometime.
Wish there were shaders for Genesis 3 available for Blender Cycles, so also ordinary people can take advantage of them.
Well, one can dream of, for now.
Speaking of which wouldnt that be a dream pairing, DAZ with a Blender bridge so we could model objects an interchange between blender and daz on the fly. Oh the possibilities!
A couple of things...
You used the V7 with a couple HD morphs and your Cornea morph...so they will throw a 'not found' error for those of us who don't have the V7 HD add-on.
And I agree on Blender's hair...I just wish there was an easy way to convert Blender hair to something usable elsewhere. (yeah, convert to obj...but you think LAMH makes BIG, machine eating meshes...Blender's conversions are in the same category).
I really like the cycles image, especially the hair!
Here is the node setup
Whoops I always forget something, will update tht asap.
and Yeah, converting blender hair is a complete nightmare. There are some addons out there that help, but nothing of the overly polished variety. and even then that would lose the benefits of being able to shade both along the intercept and via root location. (I'm still expirimenting with them though, go tinkering!)
I consider myself ordinary people ;) Nothing special, I've just used blender for a few years, watched quite a few tutorals, downloaded other folks resourses and took them apart to see how they worked.
I could probably upload mine at some point, I still need to expiriment a bit and see how it works with other textures. And there are some good shaders already out there (I've been known to use this one for instance, and it even has some documentation), the real drag is whatever you do you will have to manually load texture maps, nothing is ever going to be click and load (sadly... there's a reason I'm going to continue to use Iray despite my undying love of blender hair)
@wolf359 I actually organized my shader setup: put it in a group, used frames. I'm super proud, normally I just make uninteligible noodly messes (must be the pastafarian in me). look at how beautiful it is.
Oh and wolf, if you want a super fast sss aproximation you should investigate the ray length node + translucence. its pretty blazing (well relatively)
I can hardly agree on that ;) Your Blender renderings are exceptional...
Thanks for the link and Cycles nodes images.
Why use Genesis? I'd say use the Lee Perry Smith scan from infinite realities. Get the files here:
http://www.jonasavrin.com/2011/01/15/free-3d-ir-head-scan-release-smart-hdr-ibl-vray-2-0/
There's a lot of comparison shots in Lee Perry Smith's original thread on CG Feedback for reference sake. http://www.cgfeedback.com/cgfeedback/showthread.php?t=751
Hell, i think most (renderer) vendors use it in their galleries to showcase what you can get as far as skin setup.
Or the Digital Emily from the Wiki Human project:
http://gl.ict.usc.edu/Research/DigitalEmily2/
One of the best skin renders with Cycles. For reference.
The 'making of' thread with included node setup - http://blenderartists.org/forum/showthread.php?379147-Skin-in-Cycles-Emily-2-1
The head does have skin.
And the head is particularly good for testing skin since we tend to focus on the head when looking at people. I'm looking at your render and it also only uses the skin on the head parts. The node setup or materials you do for the skin on the head shouldn't differ much to other skin parts.
If you want a full figure, here's a free scan from Ten24.
http://ten24.info/sample-scan/
I used genesis Because most people here use genesis, and more people here have a frame of reference
also I tried Emily once but the hiresness of the textures basically shut down my computer
Same here...I figure I'd need to max out RAM (32GB) to prevent dropping everything to virtual memory (no way it's going to ever fit on a 1 GB video card).
Just a quick note on the part quoted: cycles can do progressive rendering too. On the Render tab under Performance check "Progressive Refine." Then you can set your samples as high as you think it will take and stop it early if it looks good before that just like you do with Iray. It's a little bit slower to render but being able to stop it when it looks "good enough" saves a lot of time in the long run.
On a related subject, I wonder if you could post something about any render optimizations you are doing in either renderer for time? I'm not very familiar with Iray but in Cycles for example you can turn off caustics and reduce the number of bounces separately for Diffuse, Transmission, Glossy, Transparent and Volume - the defaults on all these are way higher than you usually need and reducing them can dramatically speed up a render at little to no cost in quality, especially in a simple, open scene like this. It's always difficult to compare render times across renderers but it might help a little bit to be sure each one is set up for the best results for this scene.
If you can't render Emily, the Lee Perry Smith should be OK. Even with cards with 1 GB RAM. And the Lee Perry Smith model have been used by a lot of people so there'd be ton of references. Anyway, the quality reference should be something close to the Cycles Emily render.
I think you're missing my purpose for this a bit, My goal wasn't to make an absolutely perfectly real or great render. I do have the lee perry head, and the ten24 one, I've tested stuff on both of them in blender, but I still think I get more usable information for my purposes with genesis, namely how the engines render genesis, and how they work in a workflow (with daz figures). Also while there are lots of renders of the heads floating around, they all have completely different lighting, so are much less usable as a base comparison.
BTW. Updated the scene files to no longer use any extraneuous morphs. woo
Then why name the subject : 'Skin in Iray vs Cycles vs ???' Should've named it 'Genesis 3 in Iray vs Cycles....." I'm merely going by the thread name and ultimately how we all can learn from each other about how to setup and render physically based skin, in whatever renderer. Or at least something that's as close as possible to skin, not plastic or wax.
I am. Like I said, the name of the thread is 'Skin in iray and Cycles...' Doesn't say 'Genesis 3 skin in iray and Cycles...'
Using freely available scans are actually a good idea. Everyone have access to it and they don't have to download DAZ Studio or the Genesis 1/2/3 starter essentials to get the model or textures into their app. The file sizes for both are larger than say, that Lee Perry Smith scan. The textures are captured by camera, not painted. Very important especially for displacement.
If you want to haze the same scene across different apps (not just renderers), just export it as an FBX file (figure, texture, camera and light position). With a free model, there's no copyright issues of mesh exporting like if you're using any DAZ models (distributing the actual mesh or textures).
The current setup for comparison forces you to have DAZ Studio and the Genesis 3 Starter essentials, load the scene and manually transfer it to other app to get the same light and camera placement.
Yes. The Title is "skin" genesis has a skin texture, So how exactly is the title incorrect?
Technically I guess, the thread should be named "Genesis 3 skin and eye shaders in Iray, Cycles and hopefully some other renders controlling for factors such as different textures and lighting" But i figured that might be a bit of a mouthful ;) I did however mention all of that in my introductory post.
You are more than welcome to do a comparison using whatever mesh and texture you want. I wanted to use Genesis. I even have some reasons: I wanted to include eyes, and teeth, My preferred Iray setup uses the grey SSS map of which I would have had to create my own, or figure out a different shader setup, and as i mentioned before I wanted something relatable to my workflow.
Here's mine :)
OOOH!
I like how soft the skin looks, The shadows on the neck softened up really nicely. I also really like the specular on the eyebrow, Its a tiny thing, but it really makes them look a bit more 3d and less painted on
Here's 'part' of mine...I probably won't be able to get back to this until next week sometime to do a full run...
I should probably say which renderer this is...3DL.
Damn, I like that Octane render.
/sigh
I feel a large and expensive outlay of cash in my future. :(
Here's my custom V7 Iray shader, with alternate eye maps
Thank you. I am very pleased with the results I am able to get with this shader. I'm also always tweaking it to see what else I can do or add to it, which often ends up with me just playing with skin shaders and not really rendering anything lol >_>
3delight in DAZ Studio. 3 minutes on 4770K. No hair yet, cause I'm still tweaking the hair preset. I haven't gotten around to setting up 3delight on Houdini yet. Not using the scene though and definitely not Genesis 3.