Catchlight overview and how DS 4.8 handles the process....
Greetings all.....I'm a master photographer that has been using Poser to aid in the teaching of photography based lighting. However, the last few updates of Poser using the DSON importer has been a disaster for me and so have brought DS out of the closet and updated it to 4.8 running on a Mac Pro 2013.
After perusing the DS, Renderosity and other forums as well as extensive web searching I have yet to find a place, document, or tutorial that even begins to explain light reflection in the eyes. My one big gripe with all the Daz/Poser output has always been the fake looking eyes and it seems like now most everyone is using reflection maps which is ok in its place for static output. However, with Poser, you can set the specular color, hilite and size for each eye component and get realistic catchlights that do a good job of mimicing real world studio lighting. You can also see this process previewed in real time as you move the lights around because the catchlights show up just fine which makes it easier to explain the subtleties of simple and/or complex light placement.
I would appreciate any feedback on exactly what is happening here. I'm not a newb and use Poser and Vue Inifinite quite a lot but DS 4.8's lighting scenario just doesn't make much sense for real world simulation although I do like the iRay implementation and the use of emmisive light sources with it.
I've used G2 and G3 builtin and custom people as well as own V4 and V6 with various addons.
Regards,
MT
Daz 3D is part of 
Connect
DAZ Productions, Inc.
224 S 200 W, Suite #250
Salt Lake City, UT 84101
Licensing Agreement | Terms of Service | Privacy Policy | EULA
© 2024 Daz Productions Inc. All Rights Reserved.
Comments
In D|S with Iray, you can remove the artificial eye glints in the eye MATs, and go straight with light-based reflections. This subject has been discussed in several threads here since the release or Iray, but in a nutshell:
1. Apply a suitable Iray surface to the eye reflection (or whatever it's called in the specific model you are using). Thin Water is often used.
2. Remove the painted-on eye glint, if not completely, then by substituting the mask with an all-black image.
3. Apply an cornea bulge morph to produce a rounded eyeball. This will aid in proper reflections.
4. Adjust your lights accordingly.
In Iray, there is no reason to futz with individual eye components to mimic eye reflections. Forget what you did in Poser. Iray is a physically based renderer, and follows (as close as practical) real light physics, and the interaction of that light with real life materials. The surface of a real eyeball is basically a membrane of water, so a material set to reproduce those properties is a good place to start.
Thanx for the feedback
Number 1 was what was mainly killing me as I had tried numerous surfaces but none just looked right....probably my not being familiar with how DS deals with specularity.
Number 2 took some time to figure out but I used a different approach.....the documentation/wiki-itis deal that Daz uses sucks big time as there is nothing that really tells how the varied tools work, only what they do.
Number 3 is one of the reasons DS and Poser are dirt bag on catchlight generation as a slight light movement will cause the catchlight in one eye to be way out of balance with the other.
Also, I had done numerous searches on variations of catchlight, eye lighting on these forums and found none of the items mentioned above. Web searches will show you plenty of tutorials use reflections or plenty of links to the eye shaders on the stores but nothing useful so once again thanx.
MT
You need to be specific which renderer you are wanting to use. The techniques are different between the older 3Delight renderer (similar to Firefly in Poser) and Iray. With Iray, specularity, reflection, index of refraction, and other aspects come from the mathematical implementation of the shader materials.
There was a whole thread not long ago (a month or so?) about rendering eyes under Iray. It also comes up in other Iray threads, such as the several "Show Us Your..." threads. Be sure to do a Google search for these terms. The search feature of the software this forum uses (VanillaForums) is rather brain dead.
iRay for the renderer in DS as I was using Reality in Poser but hated the fact you had to render to see the lighting fx.
If DS had decent docs we wouldn't have to wade thru all this s**t.
Thanx,
MT
Update on this issue...I can get a rendered catchlight but I don't see anything in the preview using textured shader as I move lights around.
I've tried various light sources but none show in the preview itself. Positioning lights to maximize catchlight reflections doesn't seem to be able to happen in D|S like it does in Poser.
Any ideas anyone?
Thanx,
MT
You need to switch to NVIDIA view in your viewport. Depending on your machine, this may be a useful technique, or it may be totally useless, if you have slow hardware. (For some jobs, you can use the Aux viewport, which can be sized smaller than your regular viewport. Smaller=faster.)
In Poser, the preview uses OpenGL that can display some aspects of the final rendered scene. Iray does its own thing; to see how things will look under Iray, you must use the Iray preview.
Being a photographer should assist you in working with Iray since it is a physically based renderer and light works in Iray as you expect in real life. The photometric lights can even use IES profiles ( http://renderman.pixar.com/view/DP25764 ). You can use mesh lights and work with bounced light. I think you'll have fun with this and if you have any tips for us, less photographically knowledgable, we'd appreciate it.
Tobor,
Unforturnately my 6 core Mac Pro 2013 doesn't support Nvidia GPU as it's AMD/ATI. I've tried the iray viewport but realtime is like 20 seconds even on a tiny window so not viable there. I'm gonna bring in my i980x as it has a fairly high end Nvidia card in it and try that.
Cris,
Even though iRay is touted as a real world light renderer the tools that accomplish this in D|S are horrible. Light falloff and light modifiers are very difficult to setup in direct comparison to say a typical 4 light studio setup. I've tried all of the availabe studio light setups but none of the vendors seem to understand actual photo based lighting setups. I have found no viable way of actually measuring light falling on an object/scene in D|S and to me this is a major shortcoming as you're stuck in the old 'render and wait' scenario to see what you got. I can measure luminance values in Photoshop but again, you need a complete render to do so as the noise in iRay partial renders convolutes any luma reading accuracy.
I'm very familiar with IES profiles have used them as far back as Caligari on the Amiga (yep, I'm an old guy) but you can't get profiles for flash tubes. And being a pro shooter for going on 40 years I know all the tricks with gobos, scrims, reflectors, diffusion panels, softboxes, ringlights, beauty dishes, and pretty much any oddball thing used for a light modifier. Also, a flash tube has a high output for a short duration and all lighting in D|S is continuous.
I'd like to create some useful lighting scenarios for real world photo but just don't have the time to do so. Maybe once more people get a handle on iRay things will start to appear.
Thanx,
MT