Lighting Challenge #7: An Eye for an Eye

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  11 November 2006
I am sorry but I dont know how maya hair tools work so unfortunatellyI cant be of any help.

If you want to avoid geometry for the eyebrows though, you can use a reflection/specular & a bump map. It can give quite nice results with good maps.Check TinyCerebellum's pic(the first one in the previous page),he used this technique and his render is very realistic.

A few tips I can give you for very realistic results/renders :

Use transparency for the eyelashes with refraction.
An Index of refraction: IOR= ~1,35 - 1,4 should give good results and use absorbsion so they are not fully transparent but slightly color tinted depending on geometry-hair thickness , alternatively just use colored refraction.

If you want to push things further use glossy refraction(and maybe reflection) to simmulate the blured refraction/reflection that the 'imperfect' hair geometry produces (I refer to the hair 'scales' that you can see on hair of all types under a microscope ).This will increase rendertimes and you'll need to set the refraction depth value for the raytracing rays to 3-6+ but it will add to the quality of the final result.

If you want/can mix the result with an sss shader and experiment.If you want faster results just use an sss shader and avoid the refractions.

Hope this helps


Last edited by mer : 11 November 2006 at 11:22 PM.
  11 November 2006
@donvlatko: We were fortunate to have the model for the challenge and it came with eyelashes already in poly i think. Im a maya user also but not much experience yet.. You can use several things in maya like fur, paintfx and hair to create.. i recomend paintfx is kinda cool also some people in the thread use this techniq k ..

@Womball: Check the thread there a lot of XSI users in here
  11 November 2006
thanks guyw, now i AM hveing problem to attach, I mean when my eyes close so my eyelish also moves
  11 November 2006
The thread doesn't answer my question about the iris texture, I just need to add something. Also I would like to know if there are any other free HDRI sites like
  11 November 2006
Originally Posted by Womball: The thread doesn't answer my question about the iris texture, I just need to add something. Also I would like to know if there are any other free HDRI sites like

To be honest for iris texturing I prefer photo textures for the iris.Its easier and the results are more realistic.Of course you can always make an iris with procedural texture maps in your 3d app but I dont see the reason to bother.'Cleaned-up' photographs work best for texture maps because they usually have all the little things like 'randomness-impurities' that miss from most procedural maps.

My advice is always use LOTS of REFERENCEGenerally if you want to mimic reality then you need to understand how things work and why they look as they do.Most of the times biomechanical functionality defines how something looks.

By the way there are MANY different types of irises, if you take a look at many photos you ll see what are the main differences and common parts and then you ll be able to paint one that will look as if 'could be a real one',one that incorporates all the little things that 'need to be there'.

The same goes for face modelling! For example there are many different types of head shapes/ nose shapes / ear shapes /mouth-lip shapes.
BUT you can just use a nose from guy A(who is fat) and put it on the face of guy B(vey thin one).It will most probably result in a very 'wierd' looking face!
There is usually 'harmony' between the facial feautures of a person.Even people with 'ugly' idividual features can look 'beautiful' or at least 'nice looking' (you can notice this with many actors face) , while others ..that have nice idividual features dont have them 'well-combined' and this results in 'a not so good looking face', if you know what I mean.Harmony is everything.

EDIT:Oh and on Debeve's site there are a few NEW very good quality HDR images in Open Exr format(similar/better to .hdr format).If you havent tried them yet they are worth a look.


Last edited by mer : 11 November 2006 at 07:53 PM.
  11 November 2006
I am looking for eye photo, high resolution to use as map, can I find some where for free?all the map I find are small size and resolutions....:(
  12 December 2006
Actually I found many high rez eye photos on google.Try search with keywords 'eye close-up' , 'eye macros', 'iris close-up /macros/photos and other combinations related to eyes,also follow the links and search in the sites related to 'opthalmology' etc. you 'll find way more than you may think if you dedicate a few mins

Here is an example from wiki site..

(zoom in for full detail.You can see in this pic that the hair /eyelashes are indeed tranparent/refractive and not opaque.)


Last edited by mer : 12 December 2006 at 01:46 AM.
  12 December 2006
thanks man!
  12 December 2006
Originally Posted by donvlatko: thanks guyw, now i AM hveing problem to attach, I mean when my eyes close so my eyelish also moves

Did you ever manage to figure this out? I'm going to have to be dealing with this issue soon.

Btw thanks for the help guys! I hope to have something posted soon, its crunch time right now so its rough.
  12 December 2006
I am still looking for best solution, one would be rivet but I am looking for better our combination
  12 December 2006
I've found the time to tweak a bit my image. Add a texture to the patch, changed iris, add DOF. Critiques are very wellcome. I would like to improve eyelashes and the reflection of the Inner and external part.. any clue
  12 December 2006

Is he supposed to wear a contact lens , or is the 'ring' you can see around the iris due to intersecting geometry?

The iris-white part border should be a little more blured IMO, and increase the value of the bump map on the skin, it looks way too smooth.
The cornea looks kinda small, considering the lighting is not very intense in this image.Usually it would be of that size under very bright sunlight.

Perhaps you could also place the cornea at the center of the image so the whole subject is more centered.

  12 December 2006
I worked on 'my' eye a little more ,I used displacement for the iris for better detail and I used refraction for the eyelashes.I scaled and rearanged the position of the upper eyelashes and duplicated some of them to make some more.I noticed that in real ones the upper set has 3-4 rows instead of just one (like in the original model).

Here is a 'geometry-only' render without shaders, just displacement&bump maping:

The displacement map for the iris really helped to bring out the details and correctly get illumination and shadows.You can see that although the geometry looks very 'rough' in this image where I used a simple phong shader, in the next pic with the sss skin shader aplied , the details , creases and bumps almost dissapear as they become 'blured' resulting to a more smooth natural looking skin.

A render straight from the renderer / no post work:

And the final render with post work , again no DOF, FG/GI , just 2 area lights, rendertime ~1hr on my old 2Ghz AMD-512Mb ram pc:

Last edited by mer : 12 December 2006 at 02:50 AM.
  12 December 2006
@Mer, thanks for the suggestion I will send another try soon
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