Iray brown eyes not brown!

Sassanik

Okay so I recently did a render using Iray, and much to my surprise my brown eyes did not look at all brown when they finished!

I admit I was using old V4 mats, but its still odd. Is there an easy to fix this issue?

See the attached pictures, same character rendered in 3Delight and Iray.

 

Amy

mjc1016

Can you post a shot of the unrendered eye?  And maybe a little bigger versions of the rendered ones?

I'm not entirely sure that they are the same diffuse map...

I've had that problem with Luxrender before, where the 'default' eye color is what's being rendered, after changing it.  It's like the change isn't passed on.  Or if the color change was made by adding a diffuse color, sometimes strange things happen.

Tobor

The character's skin tone has changed color, too, so there's no surprise the eye iris is not what you expected it to be.

One possibility: The Iray Uber surface automatically applies a gamma correction to most surfaces, and this correction matches the gamma output of the Iray renderer. (Gamma affects the lights to darks in a scene; if it's set wrong, it can look too washed out or contrasty, or change colors). Many textures, especially older V4 nes, were not made with gamma correction in mind, so changes in skin tone and color are usual. Try some other textures. If you have Photoshop, Gimp, or another good image editing program, you can modify the textures you are using. 

Another possibolity: As mjc notes, it's not uncommon in these old V4 materials settings to add a base color to textures. You have to undo a lot of old and unreliable techniques they used over the years.

JD_Mortal

Another possibolity: As mjc notes, it's not uncommon in these old V4 materials settings to add a base color to textures. You have to undo a lot of old and unreliable techniques they used over the years.

Yes, the older objects materials were simple, and lacking some extended rendering standards that did not come into use until after V4. Additionally, some older settings were dropped from the render, with the conversion to DLite and more dropped going to IRAY, while IRAY also picked-up additional material settings that the old rendering or DLite had.

Remember, these colors were made when there was only an early version of DLite. All the old models have deeper reds, (Which would turn those blue-eyes brown.) This included SKIN, which, was not true to the actual mapped images. (Look at the skins and you see they are flesh-peach, but all rendered tan/red, which we all battled with bright lights and bumping-up things like purple velvet and adding red/pink subsurface and blue tinted speculars. Now, those odd colors used to fix the past, give us blue/pink/peach skins that are super-bright, while those with missing values are red/pink.

(Actually, Daz should auto-detect that those objects have older materials and counter-bump those values to correct them for IRAY and for DLite... But it doesn't. You have to do that manually. The good news is, once you do it for one skin, it fixes all your models. Just load-up one model with each skin and render it... Balance them until they all look pink/flesh, not orange/tan and blue/pink, until the original artists, or DAZ fixes the issues internally and does an update to all the old models, or provides an IRAY fixed version of the skins we own, for V1-V4/V5/V6)

When in doubt, find the skin-map and look at it, using it as a reference for the final rendered image. Just remember that the materials have individual settings that modify your lights and the "Environment", which includes reflections from lights and the environment mapping "fake images that you only see in reflections like chrome and off wet surfaces like water in eyes."

Sassanik

The eyes I am using are P3D's Anouk Holiday freebie. 

Here are larger images, and an unrendered one.

mjc1016

Did you apply an Iray material or rely on an autoconversion?

What are the scene lights?  If the camera headlamp is still on, then it will contribute to washing things out.

Also, the stark white in the diffuse color is going to contribute to 'blowing things out', in the Iray render.

The faked/baked reflections on the cornea aren't helping anything, either...

 

Sassanik

Used auto conversion and the standard lights, ie no custom lighting just the default stuff. 

 

Amy

Tobor

You will need to apply the Iray Uber shader to all the surfaces of the character, or else there's no way to know what you're going to get. The "auto conversion" just does the basics so that the Iray engine gets the MDL surface definitions it expects. You want to manually convert those surfaces first to native Iray. See the first surface icon Shader Presets/Iray/Daz Uber (you will need to have installed the Default Lights and Shaders for DAZ Studio 4.8+ content).

You should also clear all scene lights so that there's no 3DLight stuff in there, and either use the default "Ruins" HDR for a simple environment, or add one or two point lights. Don't use a light set designed for 3DLight.

mjc1016

Tobor said:

You should also clear all scene lights so that there's no 3DLight stuff in there, and either use the default "Ruins" HDR for a simple environment, or add one or two point lights. Don't use a light set designed for 3DLight.

Actually...that shouldn't matter.  Because sometime during the beta period they wrapped the default lights together, so that they became context sensitive.  So by just switching from 3DL to Iray, the default lights should be correct.  Now for other lights...Omnifreaker's UberArea/UberEnvrionment, any ShaderMIxer or ShaderBuilder lights...then yeah, they'll need to be swapped/deleted.  But for the point, spot and distant (Iray abhors distant lights, any way, so don't use them), they should give the correct features for the chosen render, without doing anything.

Tobor

I meant lights designed for 3DL (i.e.., they use 3DL shaders), not just Daz Studio's built-in lights. I suppose I should have made that clear, but I'm unsure how much of this the OP is familiar with.

I recall for a time we had unparametric and parametric spots. I'm glad they did away with it.

FWIW, the sun is a "distant light," or in the Iray programming documentation, defined as LIGHT_INFINITE. If Iray doesn't like D|S's distant light fixture, there's probably something wrong with the implementation of the fixture. Iray should treat it the same as it does the sun. That is, "sun" and "distant light" are programmatically the same, at least according to the docs.

mjc1016

I think it's more that it is a parameters conversion screw up, more than anything else...it usually blows out the scene and needs a ridiculously low level to not do so.

vwrangler

In my experience, it tends in part to be a really weird reflections issue (although this is on eyes that have been fully converted). It helps to put the iris and sclera textures in the glossy and transmission slots for those surfaces.

mjc1016 said:

Tobor said:

You should also clear all scene lights so that there's no 3DLight stuff in there, and either use the default "Ruins" HDR for a simple environment, or add one or two point lights. Don't use a light set designed for 3DLight.

Actually...that shouldn't matter.  Because sometime during the beta period they wrapped the default lights together, so that they became context sensitive.  So by just switching from 3DL to Iray, the default lights should be correct.

Yes and no. Yes, the right options will be there; however, if the 3DL lights were in the scene before you shifted the render engine from 3Delight to NVidia Iray, the photometric options will be off and will need to be turned on. Newly created lights after Iray is turned on will have photometric on by default.

mjc1016

Sholuld be...

Well, I guess 'off' is better than nothing.