Oily/Wet Iray Renders

pfunkyfize

I think there's only so many pool/Jacuzzi renders I can do before the wet/oily skin look begins to be a bit much in everyday non-water related renders. ;)

This happens when I use the Iray optimized materials for G2F.

What can I do to take the sheen of sweat/oil off my charcters at render time?

 

Thanks!

fastbike1

How about posting an example? I don't get any of that in my Iray renders.

pfunkyfize

Nice looking renders! Do you do something to the shader settings to get those looks with no slimy skin?

here's what I am talking about slimy/oily:

pfunkyfize

Another sample of slimy sweaty skin

 

Esemwy

For me, that's usually a reminder that I left the headlamp on. There are a few base skins, though that have that tendency regardless and you have to tweak the glossy reflections. 

pfunkyfize

Esemwy said:

For me, that's usually a reminder that I left the headlamp on. There are a few base skins, though that have that tendency regardless and you have to tweak the glossy reflections. 

So that sounds like there's a switch for the lamp or something somewhere? I'll try finding that!

Thanks!

SpottedKitty

pfunkyfize said:

So that sounds like there's a switch for the lamp or something somewhere? I'll try finding that!

It's in the Parameters tab for whichever camera you're looking through (note that this exists for every camera in your scene; important to remember when you switch from one camera to another). Just switch it from Auto to Off. The Auto setting is supposed to detect lights added to the scene and turn the Headlamp off, but some types of lights aren't properly detected.

As for the shiny skin, are you using the Uber Base preset to convert to Iray materials? There's also G2F and G2M specific presets (in each figure's Materials folder) that apply the proper different kinds of settings — a bit of subsurface scattering on the skin, a bit of gloss on the finger and toenails, water (for the reflections) on the eyes, etc. The Uber Base just applies a "best guess" conversion to everything, which doesn't always work all that well for people and their complicated surfaces.

Richard Haseltine

There's also a universal hedlamp setting in Render Settings.

pfunkyfize

SpottedKitty said:

 

As for the shiny skin, are you using the Uber Base preset to convert to Iray materials? There's also G2F and G2M specific presets (in each figure's Materials folder) that apply the proper different kinds of settings — a bit of subsurface scattering on the skin, a bit of gloss on the finger and toenails, water (for the reflections) on the eyes, etc. The Uber Base just applies a "best guess" conversion to everything, which doesn't always work all that well for people and their complicated surfaces.

Ah! I am using the Uber Iray base for everything on the scene. Then, I go back to the characters, select their skin surface, and then apply the Iray G2Fmaterial. This brings up a burning question. Is the Iray G2F material messing up the Iray Uber base or the Uber base messing up the G2F material?

One of my renders has two women in it. One a V4 and the other a G2F with all the Iray material on her. The V4 has her default skin on. When I rendered them, the Iray optimized charcter and set props are shiny and the V4 is not. I can't remember if the headlamp is on but because the V4 doesn't have that oily appearance like the G2F I am thinking that it's the Iray materials/Uber base that causes the shine not so much the headlamp.  The example I'm using is a render called 'The Occupational Hazards of Espionage' where you see the default skin/legs of V4 in the same light as the spy on the ground who is a G2F with the Uber Iray materials and optimized Iray G2f material. You can see the red spy is shiny and the black spy is not.

This would lead to my next question, what settings in the surfaces tab should I change to remove excessive shiny/oilyness ? It looks like a lot of settings I would have to change but I am not sure what a chain reaction I may get if I mess with one/all the right or wrong combinations...

Thanks for your eyeballs on this!

 

Richard Haseltine said:

There's also a universal hedlamp setting in Render Settings.

Thanks this is good to know!

SpottedKitty

pfunkyfize said:

Ah! I am using the Uber Iray base for everything on the scene. Then, I go back to the characters, select their skin surface, and then apply the Iray G2Fmaterial.

Skip using the Uber Base — you're converting twice, and the double conversion might be stripping out details that aren't important to non-people models. Also, when applying the G2F Iray MAT only to the skin materials, you're missing out on properly converting all the non-skin materials (eyes, inner mouth, nails etc). Just use the G2F converter once on all surfaces, and it'll do everything automagically.

pfunkyfize

SpottedKitty said:

Skip using the Uber Base — you're converting twice, and the double conversion might be stripping out details that aren't important to non-people models. Also, when applying the G2F Iray MAT only to the skin materials, you're missing out on properly converting all the non-skin materials (eyes, inner mouth, nails etc). Just use the G2F converter once on all surfaces, and it'll do everything automagically.

Okay,

So if I am reading this right, I should:

1: Only use the Uber base for the set and props - no characters/people.

2. Select the Character at its root node level, then apply the G2F Iray MAT to the entire character in the surface tab to get all those missing parts ike teeth nails etc....

Right on! I will try it... Thank you!

SpottedKitty

Yes, that's right. Note that some things should still need other Iray materials supplied in the Starter Content (glass, water, shiny metal, emissive lights, etc) for best results. Or, of course, if you've bought other Iray shader sets like Real Lights or UHT Hair, just use those.

And watch out for any surface (including skin) with Displacement applied in 3Delight; because of the different way Iray handles displacement, this will need some poking and prodding to work right.

maclean

For many things, you don't need to use the Uber base at all.

DAZ_Spooky said "The Iray Uber Base only needs to be applied if you intend to adjust the shaders specifically for the render. If you leave them as 3Delight Shaders, the auto-conversion that happens to render does exactly the same thing as applying the Uber Shader"

In other words, if you're not going to tweak the surfaces on props, etc, there's no point in applying Uber base, since DS will auto-convert the materials anyway.

Ostadan

maclean said:

For many things, you don't need to use the Uber base at all.

DAZ_Spooky said "The Iray Uber Base only needs to be applied if you intend to adjust the shaders specifically for the render. If you leave them as 3Delight Shaders, the auto-conversion that happens to render does exactly the same thing as applying the Uber Shader"

In other words, if you're not going to tweak the surfaces on props, etc, there's no point in applying Uber base, since DS will auto-convert the materials anyway.

I thought there was a bit of time saved in the render startup, though, because the surfaces do not have to be auto-converted to Uber if you've already done that manually? 

Tobor

The auto conversion takes time. You can sometimes see it in the log: I believe whenever it notes the MDL JIT (just in time) conversion, Iray had to make that extra step. Plus, with any JIT conversion you really don't know what you're getting. As it is, the standard Iray Uber base is too glossy for many things, but at least tweaking there leads to consistent results. You can't tweak a 3DLight surface and expect reliable results with JIT conversion.

KurzonDax

Tobor said:

The auto conversion takes time. You can sometimes see it in the log: I believe whenever it notes the MDL JIT (just in time) conversion, Iray had to make that extra step. Plus, with any JIT conversion you really don't know what you're getting. As it is, the standard Iray Uber base is too glossy for many things, but at least tweaking there leads to consistent results. You can't tweak a 3DLight surface and expect reliable results with JIT conversion.

Everything said above, plus if you're doing a lot of spot renders, the time to auto-convert, even if minimal, starts to add up.  It's essentially making the engine perform the same conversion over and over again.

pfunkyfize

So if I am reading all this right,

If I manually add the Uber base, that is a step that will shave a little bit off render times because the auto-convert won't have to do it? I'm all for shorter render times!

Thanks!

KurzonDax

Essentially, yes.. with a caveat.  What it looks to me like is all the engine is doing is applying the Iray uber base to surfaces using whatever texture maps were originally assigned to the surface.  I've noticed that for basic surfaces, it will also try to match things like glossiness when it can. Truthfully, this probably takes a very tiny amount of time (in human terms).  However, if you have a whole bunch of surfaces in the scene, it could ( and does) add up.  If you're doing spot renders repeatedly, I think it absolutely makes sense to just apply the Iray Uber Base once yourself. It also allows you to have control over how the surface looks instead of leaving it up to the engine to make a semi-educated guess.

 

Tobor

One important point is that once you apply the Uber surface, you now have shader nodes that Iray understands. So if you need to tweak something, you can, and it will have a reliably consistent result. Tweaking a shader meant for some other renderer isn't predictable.

 

mjc1016

And don't forget the long term time savings, if after you've converted to Iray, manually, you save that conversion as a preset, so any time you use that item in the future, nothing will need to be done to it.

KurzonDax

I also save shader presets without images for general surface types that I run into frequently.  For example, I have several generic presets for skin, rock/stone, wood of various types, a few different types of walls, etc.  Saves quite a bit of time by giving me a good starting point with new items.

pfunkyfize

Okay. the shader vs texture vs material is a new concept for me, I've just been using shaders to change the look of an object. When I change a shader in the surfaces tab, am I also changing the material automatically? I see that I have the option to leave the texture alone with a ctrl-click of the shader but I don't see anything that touches materials when applying a shader.

I imagine if I start building my own 3d objects those concepts would become clearer to me but for rendering purposes only, the material and texture are all separate entities?

Once a gigantic render on my pc stops running I will try all these great experiments - thanks again eveybody!

KurzonDax

Yeah, the lines between texture vs. shader vs. material can seem pretty blurry.  Here are my simpleton definitions that may (or more likely may not) coincide with industry standard definitions, but they work for me:

• Texture - These are the images used for a given surface, including the diffuse, bump, glossy map, metallic flake map, thin coat map, normal, displacement maps, etc.  Note that a surface doesn't require any one of these to be specified, and that some maps are specific to a shader.  For example, most of the MDL shaders for iRay don't allow you to (easily) specify any of the maps as they are hard coded in to the shader, or not used.  Much of the time, textures are just composed of a diffuse and/or a normal/bump map, and sometimes a specular map.  I also lump colors assigned to surfaces as being part of the "texture".
• Shader - A shader is essentially a set of instructions that tells the renderer what a pixel should look like (basically what color it needs to be).  This is determined by the textures, light sources in the scene, and how the shader is configured to react to light.  The shader also defines which specific texture maps can be utilized for a surface.  Lastly, shaders are specific to a render engine.  Daz was nice enough to build in an auto-convert for most 3Delight shaders, so you don't have to manually convert 3delight shaders to Iray.  For best looking results, though, you should take the step of converting them yourself and making adjustments (usually to the glossy parameters).  It is very important to note that some advanced 3Delight shaders use code specifically for 3Delight, and won't work with Iray.    
• Material - In my world, a material is what you get as a result of a shader combined with specific texture maps.  For example, the Iray Uber Base shader can be used with mny different textures.  So if I use Uber Base with some brick textures, the whole thing together would (to me) be a brick material.  If I swap those textures out for images of dirt, but use the same Uber Base shader, I now have a "dirt" material. However... the term "material" or "mat" is often (mis)used to describe just textures or just shaders.

In Iray, the term "material" only matters much if you are assigning material ID's which can be used to select a group of surfaces or if you are using canvases in your render process.

It's probbly worth noting that products in the shop may refer to as coming with "3Delight mats" or "Iray mats".  This means that the materials assigned to surfaces of the objects have been configured to work with one or both of those render engines.  A good rule of thumb is that if Iray isn't specified, then assume the materials are 3Delight.  That doesn't mean it won't work with Iray, unless as noted above, it makes use of some custom shader that is specific to 3Delight.  

Sorry if this is still confusing.  Trying to shake off a summer cold, so not sure my brain is fully functioning.