Eyes (irises) in iRay.

Robinson

Can someone explain iray eyes to me?  On the left is a character with standard viewport lighting and on the right I have added 4 spots and a dark grey box (we are inside the box), two front (left and right) and two rear (left and right).  As you can see, the left side eyes are colourful but on the right side the eyes are almost black.  What's going on here and more importantly, is it correct?  The eyes are from another place (Hinky's Spect-Occular Eyes 2).

 

Richard Haseltine

The left eyes are reflecting the default HDRI image, the right eyes are in a box and if the lights are pointing towards the figure it's not a well lit box - as a result there is only a fairly dark surface to reflect (since the box is blocking the HDRI).

Robinson

So what you're saying seems to be summed up as follows:  the lighting of the eye is highly dependent (almost totally dependent in my experiments) upon bounce lighting.  For example, they look great if the room is white, not dark grey.  Direct lighting has little to no effect, including shing a low intensity spot into the eye.  So the next question has to be how do I show iris colour in a room with dark walls. Or perhaps there's something I'm not understanding about this and that it's physically correct.

Richard Haseltine

Sorry, I was answering the wrong question (at least on the face of it). What i said accounts for the difference in reflections and hghlights, while it may have an impact on the detail in the irises (from refraction) I think there may well be other factors at work - do you have the Maximum Path length set to a value greater than 0 in Render Settings?

Sevrin

Robinson said:

So what you're saying seems to be summed up as follows:  the lighting of the eye is highly dependent (almost totally dependent in my experiments) upon bounce lighting.  For example, they look great if the room is white, not dark grey.  Direct lighting has little to no effect, including shing a low intensity spot into the eye.  So the next question has to be how do I show iris colour in a room with dark walls. Or perhaps there's something I'm not understanding about this and that it's physically correct.

There's something else going on.  This is VW Margot in a completely unreflective black box with no light reflected by anything except heself and her top, lit by the single DS spotlight she's looking at, and you can easily see the colour of her eyes.

Maybe try different eye materials?

kenshaw011267

That's just the angle of the lighting and the angle of the camera. When you take a picture as an extreme closeup, like in your op, and you use portrait lights, as you used, it will wash out the eyes. Use less light, back the camera off some or something. Also 4 lights is too much, that's why you got weird shadows.

I strongly suggest looking into how real world photographers light portraits. It will help you light iRay tremendously.

Robinson

Richard Haseltine said:

Sorry, I was answering the wrong question (at least on the face of it). What i said accounts for the difference in reflections and hghlights, while it may have an impact on the detail in the irises (from refraction) I think there may well be other factors at work - do you have the Maximum Path length set to a value greater than 0 in Render Settings?

Max path length is -1.  I assume that means "let iRay decide". 

Robinson

kenshaw011267 said:

That's just the angle of the lighting and the angle of the camera. When you take a picture as an extreme closeup, like in your op, and you use portrait lights, as you used, it will wash out the eyes. Use less light, back the camera off some or something. Also 4 lights is too much, that's why you got weird shadows.

I strongly suggest looking into how real world photographers light portraits. It will help you light iRay tremendously.

I'm not so sure really.  I have key, fill and so on, and this is an experimental portrait setup (4 lights is fine).  I tried with one light at various angles and I get a similar effect, even with the luminosity dialled back and the light very close to the eye.  I'm going to try with an emissive light from a plane and see if that makes a difference.

Richard Haseltine

Robinson said:

Richard Haseltine said:

Sorry, I was answering the wrong question (at least on the face of it). What i said accounts for the difference in reflections and hghlights, while it may have an impact on the detail in the irises (from refraction) I think there may well be other factors at work - do you have the Maximum Path length set to a value greater than 0 in Render Settings?

Max path length is -1.  I assume that means "let iRay decide". 

Yes

Robinson

Same lighting in both (but only one front spot this time), left is Brooklyn HD eye material and right is Hinky's.  Brooklyn HD eyes are very flat with no highlights (hence my desire to use some better materials).  Hinky's are very dark again but have some nice highlights.  Perhaps a little glassy.  Must be something up with the shader.  I mean Hinky's look great when you have a lot of bounce lighting in the scene from all directions.  Not sure where to start looking at the settings though.

 

PerttiA

In order to track down the culprit, try setting Cutout Opacity to zero for Cornea and EyeMoisture and if the blackness goes away, try one by one to pinpoint it.

I had some problem with unusual reflections in the Iris that didn't go away and found the problem in Cornea settings.

Robinson

In the end I used eyes from another figure, as suggested above!  No time to spend on fixing the problem with this specific eye product, though I may return to it.

magog_a4eb71ab

I've had this exact same problem with certain characters. I forget what it is, but I do recall that in order to correct the problem, I loaded a 2nd character into the scene that did not have the problem and it was a simple matter of changing 1 or 2 surface settings. What appears to be happening is the pixels on the irises don't seem to be converging enough(kind of like what happens when knuckleheads add a little refractive index weight to the teeth). So I would try looking at those settings and compare them to a different character. Chances are, the refractive index settings for the water layer covering the irises is wrong and/or something in the glossy settings. Just a guess.