Show Us Your Iray Renders. Part IV
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It's at the top of my list, Tobor. Just experimenting with other options. ;)
More magic of collision, a droid in a One Man Band shirt.
This is a WIP as I am still working on it as the moonlight is too harsh for me
As you can see the lights are shining on the walls and street.
I can't wait to get fit control and ultra bodysuit, but until then, I managed to wrangle the uniform in my webcomic to fit reasonably well. Here's a before/after of the uniform on the main character (the uniform is pretty simple, a 'wear all the time' frock coat/robe)
Edit: And this time picture
Ha ha, you trickster! You employed the age-old Hollywood technique of wetting down the street for a better "read."
They did the same, for example, in the parking lot scene (shot at Puente Hills Mall east of LA, for those interested) in the original Back to the Future. Made all the difference in the world.
No I didn't, that is the way the scene comes out of the box
I have since ran the Iray Uber Shader over everything and the glossiness has almost gone in the next one. I have also thrown in a sky dome and cut the opacity to let the light through on this one. There is still another one rendering ATM with afew more changes 
I'm so happy about this... I really wanted many of the robots in my webcomic to be dressed, and now I can...
Artenius, one of Luy's fathers, also in Vanguard standard clothing.
(Although as cool as this is, it's going to be a pain having to pose the clothing for each panel. Ah well. ;)
You might be intersted in this tutorial I cobbled together. It discusses how to use the Iray Section Plane (a virtual plane for sectioning geometry) to "cut off" the top of a skydome, so that you still get the full dome, but light from the Iray Environment (or Sun-Sky) will come through. The transparency on your skydome probably isn't helping rendering times much!
You can control the ambient light from the Environment, in case it's too bright, using the Environment Intensity control.
I don't generally use sky domes just the one that comes with Iray and plug an HDRI in when I need one but I couldn't find a decent night HDRI with full moon and clouds so I just shoved that in for convenience. Anyway rendering time isn't an issue I'm retired
This started out as an experiment in getting armor to fit right. The breastplate is not fitted, it's simply moved into position and parented to the chest, tailored a little to surround the body reasonably well, and then some breast flattening morphs on the underlying figure (though I could have simply hidden the breasts).
Then a few touches of collision to get a few things to cover properly.
As usual, I started getting Ideas and embellished a little.
...I changed the lumens to the output of the 60 W CFLs I mentioned about (825 L) and it was about as bright as a single 1.5 w ceramic coated Christmas tree or night light bulb.
I also experimented with Real Lights for Daz Studio Iray. I applied the 400 W HID Sodium shader to the bulb in the far streetlight and it did little but again made the bulb itself glow as if I was in 3DL with the Ambient channel set at 100%. That is a basically a modern day streetlight (400 W at an Efficacy of 10,0000) and it should have lit up the entire corner. The shaders in this set also set to Double Sided by default.
I never apply "real world" metrics to any of the meshes I use -- they're all pretend objects and they give off whatever light I want them to. But I've heard that other users have found the luminance values for meshes to be strangely cryptic. I wonder if this is an issue of conversion calculations in the D|S programming module that controls Iray -- that is, some value is missing one or more zeros.
As an experiment, do you get more realistic results if you multiple your expected value by 10 or even 100?. In other words, instead of 825 lumens, what happens at 8250, or even 82500.
The following is the output calculation done in the shader. The scene unit size is set to centimeters. I wonder if there's an issue where it should be 1 meter? All of the other lights use 1 cm as the scene size, so this appears to be right. Anyway, just thinking out loud...
(Going to try code formatting below...let's see if it works.)
export color calc_emission_intensity(uniform bool emission_profile_enable = false,uniform light_profile emission_profile = light_profile(),uniform float emission_scene_unit_size = 0.01,float emission_flux = 500,float emission_temperature = 6000,color emission_tint = color(1)<br /> ){
color emission_color = (emission_temperature < 1) ? emission_tint : (emission_tint * math::blackbody(emission_temperature) );color intensity = emission_profile_enable ?emission_flux / df::light_profile_power(emission_profile) *emission_color / (emission_scene_unit_size * emission_scene_unit_size): emission_flux * emission_color / (emission_scene_unit_size * emission_scene_unit_size);return intensity;}
...interesting. for the lamps on the walls you just use the bulbs and they illuminate their immediate surroundings I'm not getting that at all without using extremely high settings. However for the street lamp it appears you applied the shader to the glass rather than the bulb .
I see in the second one you applied the emissive shader to just the bulb on the streetlight like I did. I wouldn't think that the size of the mesh should affect how much of the surrounding area is illuminated as again size of the mesh did not seem to matter in Reality/Lux. The bulbs used in modern street lights (not the lenses) are not very large but based on what I have been seeing based on my tests and your attachment would have to be huge in order to cast the "correct" amount of light on the surroundings.
Have yet ro deal with the interior lighting, but that is on hold until I can get the exterior lights to work correctly.
Yes, the set comes with the "wet" look for the street as a default. I turned it off in my scene saince I have a fairly clear sky moonlit backdrop.
Lux accounts for area, but the given number of lumens is spread out over that area. So a value of 1000 lumens pumped into an area of 1 m^2 will light that area to the full 1000 lumens...but 1000 lumens into an area 10 m^2 will only be 1/10 that or 100 lumens...so if the scale translation is wrong then yes, you need to go to absurdly high values to get the expected light output.
kyoto kid
Forget that first one, that was my first attempt at getting the lights to cast light when I first started messing about a few weeks ago and hadn't noticed that it was the glass that had the shader, I have moved on since I set that scene up. The second scene is the right one with the shader on the bulbs
This is the .duf file for my street lights. Merge it into your scene and shut off the originals, the ones that are mine will have the (2) after them, and see if they work. The first link is just the .png thumbnail. Right click and save as to a folder,
http://www.ftscotland.co.uk/temp/Bryce/london-emmisive-lights-01.duf.png
http://www.ftscotland.co.uk/temp/Bryce/london-emmisive-lights-01.duf
...so in effect, Iray lighting does not follow the RL model then when it comes to luminosity.
Interesting. When I use a Photometric Distant Light to supply a 'Sun" light for a scene using an HDRI that does not have one, I have to turn the Efficacy down so it doesn't wash everything out.
However with Iray mesh lights, it appears I have to do the opposite and like you say assign absurdly high values to get the desired effect. (like 60 w @ an efficacy of 100,000 to get the "real" effect of a 60w 825 lumen bulb, that seems just as crazy and "unrealistic" as lighting in 3DL).
The lights in my set for gas mantles are only 5 watts at Efficacy of 1.5. The lights in the space hangar range from 3 watts at E=5 up to 85 watts at E=15.
What I've been able to gather, and lacking any other documentation about it, the distant light (the sun is just an extension of that) is measured as lumens per square centimeter *at* the scene. This accounts for the sun/distant light being an infinite light source with parallel rays. Here, "Photometric" doesn't mean falloff, inverse square, or other qualities of local light sources, it just means the light has a luminance and color temperature control.
FWIW. other Iray forums for other software don't seem to be reporting this as regularly as here. Also, the problem doesn't seem an issue with the built-in light types. So I'm wondering if it's the implementation of meshes for emissive objkects, and the way output flux is calculated. This is actually something anyone can play with. The code snippet I provided is part of the Uber Iray MTL file. It's just a text file and is easily edited. Just make a backup first!
...do I have to insert all that code somewhere? I know jack about scripting.
As to my scene, again as you can see by some additions to the background, it is set in a modern era where the gas mantles would be replaced with electric bulbs. I've seen old streetlight fixtures use Mercury Vapour and even HID Sodium bulbs.
KyotoKid...which version of Studio are you running?
Fishtales...same question.
kyoto kid
If you right click on the .duf file and, when the menu pops up, save the file to somewhere on your computer and then use Merge to Scene in DAZ Studio to merge it into your scene. It will replace the original street lights with ones with the Emissive Shader already in place at my settings.
I shut this last render down so it is still grainy. The street lights are 150 watts at E=15 and 5500K; the interior lights are 100 watts at E=15 and 3500K; the wall lights are 150 watts at E=15 and 4500K; the distant light I have posted an image with the settings for it.
...which is a pain when using HDRIs that don't supply a "sun" (or a very good one) as the edges of the shadows cast by a photometric distant light are too sharp and don't falloff properly like they do with the Iray "Sun" (there is no "shadow softness" or for that fact any shadow controls when using the Photoreal render mode). Not critical for this scene as Moonlit shadows tend to be more "distinct" and "hard" since the light source is only about .0026 the distance away as the sun).
This is what gets me, if Iray is supposed to be so "realistic", why does it seem many of the lights it employs are apparently, not, and so much still seems to be left to "guesswork" as in 3DL?
...4.8.0.59 x64.
4.8.0.59 .....64 bit
The thing about collision target has set off a series of chain explosions in my mind.
Among other things, I now realize I can handle centaurs pretty well. This is an attempt at doing one nude, and using a simple cutout to help make the transition less ugly. Not perfect, but it's a very basic stab at it.
Also, I now realize I can DRESS centaurs without too much work, simply by having collision to the horse part. Yay!
Now if we had otters, my college campaign could come to life. ;)
I asked because there are some differences between the current version and the last beta version in light behavior...or at least some I noticed. But since both of you are running the same version, that compounds the strangeness, instead of clearing anything up. Fishtales seems to have more control and more reasonable settings...sort of what I'd expect things to look like at a given setting.
Have either of you adjusted tonemapping settings?
I always adjust the Tone Mapping settings. I set up the lights I want in the scene and then set the Tone Mapping to suit so that I can lighten or darken the image as the mood takes me. I just treat the scene as if I was using my camera to take the picture.
Bed time for me. Will have to wait until tomorrow to read any more
KyotoKid, Probably best not to change things unless you know scriping. But, you can see the base calculations they are doing. The value gets passed to the Iray engine, which -- from posts on other forums -- doesn'tseem to have an endmic problem with mesh intensities. It would just be easier to start adding zeros until you get the look you want. Maybe Daz will simplify this in future versions.
Still trying to get a handle on lighting and eyes.