This might be a good moment to clarify that the camera settings you see in the sidebar of Lux are all merely scaling factors that make the image brighter or darker. That's all. They don't affect the render. They're calibrated so that they match real camera settings for real-world light intensity, but if it wasn't for that, they'd just be arbitrary numbers.

Quote - Dont mean to be a ball buster but my question was ignored once again... I must have the plague LOL

It's compiled into the scene and calculated like anything else. It's just when light rays strike the surface, nothing happens to them. The path is continued from that point exactly as it arrived. It also consumes a bounce of your total maximum (Reality uses 25 by default, or at least it has in all the scene files i've seen). The reason it's done like this is because null is generally not used by itself, it's combined with some other shader somehow to cause only part of the object to become invisible. Things like alpha mapping, sheer materials, volume-only objects, etc. See: http://www.luxrender.net/wiki/LuxRender_Materials_Null

Quote - J, light importance is not supported in Reality 2 but it will be in Reality 3

Cheers.

Ah, great to hear.

Quote - > Quote - Is that all my sci fi renders are taking 6 to 8 each but I think thats due to all the panels coverted to light...

That does account for speed loss, also the fact they do not generate much light, so Luxrender must take many, many samples to 'enlight' your scene.

I don't know if any of this is exposed in Reality yet, but there is a way to tell Lux not to trace light paths or shadow-ray tests on a lamp: http://www.luxrender.net/forum/viewtopic.php?f=8&t=7480&start=70#p81984

Quote - Your getting into some high end stuff whereas Im going back to 3Delight for the odd render

3Delight is just as "high-end" a renderer as Lux, or V-ray, or Mental Ray, or whatever. Happy Feet 2 and District 9 were rendered in 3Delight.

Quote - In the end I dont know if adding the 2 makes that much of a difference..

It's mostly noticeable when the sun is low in the sky, at midday there is very, very little difference. See: http://www.luxrender.net/forum/viewtopic.php?f=13&t=9065&p=86474#p86474

Quote - > Quote -  It is VERY important to remember that almost nothing you encounter is going to have an IOR much higher than ~1.5, which would map to a spec color of about 55 in Reality. Going much higher tends to make things bizziarely semi-mettalic.

J, is that relegated to just the specular, or the top coat as well?

With specular, I do keep mine well under 50 in most cases, especially on skin. 

The top coat, on the other hand, I will stick to my numbers! Five of these characters have crazy values for top coats and, I think, look decent.

Nope, top coat is the absoprtion parameters, those are completely unrelated. Those ones you can set with the classic "pick a color and eyeball it" method.

=====Nerd info time=====

Lux's glossy material (and its cousin glossytranslucent) is made up of two parts: a matte base reflector (essentially just the matte material) and a glassy glaze-coating. There are 4 main properties: diffuse color, which is the albedo of the base; specular color, which is index of refraction of the glaze; absorption color, the amount of light lost passing through the glaze to the base; and roughness, how smooth or (microscopically) rough the glaze is.

Now, the glaze is a glassy substance (technically it's a dielectric, but that term is almost-synonymous with "glass" when talking about shader config). That means it has an IOR. And that it exhibits the fresnel effect. That means that an incoming light ray can either be reflected like a mirror (specular reflection) or passed through the coat. In the event of the latter, the absorption settings (aka, the top coat in Reality) will determine how much darker the ray will be once it makes it down to the matte base. Whether a ray is transmitted or reflected depends on something called the "angle of incidence". Shallower angles (such as viewing directly) allow the ray to pass through. Grazing angles cause a reflection. The higher your IOR, the more reflection you get at increasingly shallow angles

Thus: When you increase your specular color, not only do you make your highlights and reflections brighter (and remember, spec highlights are merely reflections of light sources), you make them disproportionately stronger when viewed head-on. And on top of that, you will blunt the effect of the top coat, since that only deals with light that is NOT reflected by the coat.

Make sense?

Quote - > Quote - > Quote - > Quote - Specular color = coat IOR

Hi J. This is true if the index parameter is set at 0, which is what Reality currently does. Isn't it? I mean, it we set the index to a different value than that will be the IOR, innit?

Cheers.

 

Right. If you use the IOR command itself (float index) with a valid value (I can't recall if it > 0 or 1) that will be the coat IOR, spec color (Ks) is ignored. If IOR is zero'd out or not declared at all, IOR is derived from specular color via IOR = (sqrt(Ks)+1)/(1-sqrt(Ks)).

(To save you the math, an IOR of 1.5 corresponds to ~0.04, which when reverse-gamma corrected and changed to an 8bit integer for Reality's color picker gives you about 55. For water (1.33) you get ~0.02 aka ~39)

 

Wow that just made my head hurt.  I'm glad some of you understand all that.  Can someone put that in english or dumb it down for me?

tl:dr; Keep your RGB values for specular color somewhere in the 35-60 range. The rest is just explaining the technical bits about why you don't want to go outside that range.

Quote - > Quote - Specular color = coat IOR

Hi J. This is true if the index parameter is set at 0, which is what Reality currently does. Isn't it? I mean, it we set the index to a different value than that will be the IOR, innit?

Cheers.

Right. If you use the IOR command itself (float index) with a valid value (I can't recall if it > 0 or 1) that will be the coat IOR, spec color (Ks) is ignored. If IOR is zero'd out or not declared at all, IOR is derived from specular color via IOR = (sqrt(Ks)+1)/(1-sqrt(Ks)).

(To save you the math, an IOR of 1.5 corresponds to ~0.04, which when reverse-gamma corrected and changed to an 8bit integer for Reality's color picker gives you about 55. For water (1.33) you get ~0.02 aka ~39)

Quote - The shine we try to mimic in 3D, which is essentially the oils, can be duplicated more effectively with the top coat. Strangely enough, I've found some great combonations with ethnic skin (some character's I've made promo images for are Cuban/Asian, etc.) and using a color for the top coat that one wouldn't think is even remotely like skin, gives great results. 

One fellow I have with caucasion skin uses a top coat in the area of 192 (light grey) in concert with some diffuse tweaks. Utilizing a self-made exr light file for IBL, I've gotten several renders where you'd swear its a photo. Same for an african american female, and an asian female. Lickably delicious ;-)  The asian has a top coat that looks like an orange crayon... 

Specular color = coat IOR, and thus both reflection intensity and strength of the fresnel effect. The second part is important, higher spec color not only makes highlights brighter, but they will strengthen dispropotionately on surfaces directly facing the camera. It is VERY important to remember that almost nothing you encounter is going to have an IOR much higher than ~1.5, which would map to a spec color of about 55 in Reality. Going much higher tends to make things bizziarely semi-mettalic.

"top coat" in Reality = absoprtion color + absroption depth, this is the amount of light lost in the coat. Stronger absorption will be darker, especially at grazing angles.

Glossyness = microscopic surface roughness of the coat. Rougher settings will blur reflections, resulting in larger and softer highlights.

Quote - The official 1.1 still does not have the importance brush ? or has it been updated?

If it had the refine area brush, it wouldn't be 1.1 anymore now, would it. ;)

Quote - Question for the light boffins: using a meshlight (RealityLight), is it quicker than a material converted to light?

It's the same thing, an area light is an area light. What matters is how many faces it has (the fewer the better, remember quads are triangulated and count as 2 faces). Also, lights covered by another object will be very inefficient compared to an exposed lamp.

Quote - > Quote - How do I get truly reflective glass? As I sit here (10pm), looking out of the window, the inside is reflected on the window, and I can see what is outside. In Reality, how can I do that?

The glass material will do it. Just don't use the Architectural flag. The best is to have a pane of glass that has thickness to scale.

Cheers.

The arch flag doesn't affect reflections, it just disables transmission refraction (thus also giving a transparent shadow instead of refraction caustics). This is pretty much exactly what it's for, actually. The thing you need to remember with window reflections is they mainly have to do with how bright the light is on the inside and outside of the window. If it's bright inside, the reflected light will overpower the transmitted light, making the glass look like a mirror. If it's bright outside, like a sunny day in a room with the lights off, the transmitted light dominates. So just make sure you have enough interior light. You can fudge it if you want by increasing the IOR (thus weakening the fresnel effect) or mixing in the mirror material, but neither one is physically correct, so try to do it with lightining and keep the ~1.5 IOR. (mixing in the mirror material might vaguely mimic how a one-way mirror is constructed. Which, btw, also relies primarily on having more light on the "mirror" side)

Quote - > Quote - Do not make any changes unless you really know what you are doing :)

 

LOL figured as much

If you're curious what you're looking at.... ;)

http://www.luxrender.net/wiki/Scene_file_format_1.0

Quote - I need to write them down one of these days, but going by memory here, the lower 100's on thin film usually produce a subtle blue/purple effect,  and the 300's and up have a orangy-red like the chamelion paint (dupont made it first, I think!), similar to tear-off visor shields on race helmets. I haven't used the 200 range much as the intervals are pretty wide in the color band.

I would think the light source used has something to do with it as well, but in this instance, I too prefer the 'Sun' light for quality and shadow effect, when you can get away with it that is!

I didn't mean to bash on your rez size, just curious! 

Some kind soul actually made a rather over-the-top chart for that: http://www.luxrender.net/wiki/LuxRender_Materials_Glass#Thin_Film