Tips & Tricks for Iray for newbies......

SpottedKitty · June 2015

lordvicore said:
I'm not familiar with the prop/model you are using so sorry if this info is useless or not appropriate for your needs or the model's set up...
My guess is you are trying to get the effect of glowing runes written on (not carved into) the surface of the rock?

Yes, that's what the supplied 3Delight materials are set up to do — the three glowy rock pieces have the glow outline carved into them by bump/displacement, with a masked ambient map for the actual glow. The way I finally got it to work in Iray the way I wanted, I added a Geometry Shell for the glow effect and made sure both the rocks and the attached shells had exactly the same displacement maps, min/max values, and SubD Displacement Level settings. If I don't do all of that, I get the chunks cut out of the glow coming back again.

And now that I've seen how easy it is (now that I know what I'm doing :red: ) and how good it can look, I'm going to take on all the other Orestes "eldrich glowy stuff" environment sets I have in my content. The Foreverstones first, I think, they're nice and straightforward.

Szark · June 2015

zaz777 said:
Szark said:
well I think I have answered my own q about gloss colour. There is no difference in say setting gloss weight to 1.00 with a darkish grey colour than setting weight to say 0.10 and using white. As for Top Coat colour I haven't tested that yet. But if you set the top coat thin film to a thickness of 100 and higher and keep the colour white you can get some funky colours coming through. In my case various shades of purple depending the thickness so I am not sure why that is happening.
I'm glad someone else noticed this as I had come to that conclusion as well, but hadn't quite finished playing with it.
Along those lines, I'm also thinking that what is really happening here is that the actually glossy component is the result of multiplying Glossy Layered Weight x Glossy Color x Glossy Reflectivity, although I expect the Glossy Reflectivity part is a bit more complicated, i.e. probably not linear. Part of the reason I think this is because of a reference I found, since taken down, that used the IOR of a material to create what they called F0/minreflectance/specular-color. and DAZ's documentation for the Iray Uber Shader.
The equations used on the page for the Specular Cheat Sheet I found were the following:
F0 (linear) = (1-IOR)^2 / (1+IOR)^2

- or -

F0 (sRGB) = ((((1-IOR)^2 / (1+IOR)^2)^(1/2.2)) x 255)
One example value they had was for plastic and they gave it an IOR of 1.46 which generates an sRGB of 56/56/56. Skin IOR varied from 1.41 (low reflectance) to 1.49 (high reflectance) with sRGB values of 51/51/51 and 58/58/58 respectively.
That correlates with the limited documentation we have from DAZ on the IRAY Uber Shader where they say:
Glossy Reflectivity - The default setting is 0.50 and should generally be left here in most cases. This property roughly correlates to IOR and the settings of that property. The value is roughly the same as the IOR setting of 1.5, which is a good plastic base.
They also recommend, directly above what I quoted, that Glossy Layered Weight should normally be 1.0 and Glossy Color should normally be white (sRGB 255/255/255).
So, if we are to believe the documentation we have, for a plastic material we should set Glossy Layered Weight to 1.0, Glossy Color to 255/255/255 and leave Glossy Reflectivity at its default of 0.50. That means, in a PBR world, that those settings should be equivalent to setting the Glossy/Reflective color to 56/56/56 for a different renderer or shader. The 56/56/56 value is also about in the middle of the range of skin according to that page and other references I've seen.
It would make perfect sense for the Iray Uber Shader to come with defaults that are close to values for things that might be rendered, like skin and plastic and the other materials whose IORs fall near those. At this point I'm leaning towards setting Glossy Layered Weight and Glossy Reflectivity to 1.0 and using Glossy Color as the only input for the actual strength of the glossy layer or following the documentation's recommendation of leaving Glossy Layered Weight at 1.0 and Glossy Color at white, then using only Glossy Reflectivity as the determining factor for the strength.
I'm not sure what the Glossy Reflectivity value actually is. It might have something to do with a normal, but I think the actual information is buried in some DAZ code somewhere as the uses for Glossy Reflectivity I find in irayubermaterial.mdl don't seem to directly correspond to anything that is obviously of NVIDIA origin. Without knowing what the value really means, its hard to make a decision as to which way is best.
At this point, I'm beginning to think that DAZ went a bit overboard on the complexity of the Iray Uber Shader. One other thing I saw in looking at the MDL is that there are two pairs of numbers that are both used to compute coefficients, rather than have us directly enter them. This is giving us the illusion of having more control than we have, as the inputs aren't actually independent.
One component of an IRAY material is the material_volume. It can be either the vdf() or the anisotropic_vdf() VDF (Volume Distribution Function). Both VDFs require an absorption_coefficient and a scattering_coefficient. Those coefficients are computed as follows in the irayubermaterial.mdl file:
absorption_coefficient = log(Transmitted Color) / (-1.0 * Transmitted Measurement Distance)

- and -

scattering_coefficient = SSS Amount / SSS Measurement Distance
According to the MDL_spec_1.2.2_28Apr2015.pdf, on page 63, the coefficients are specifying The probability density (per meter in world space) of light being absorbed/scattered by the participating medium. This isn't really a problem, but it is misleading as you aren't actually specifying distances, a color and an amount as many combinations of them will create the same result.
For example, setting SSS Amount and SSS Measurement Distance to the same value, any same value, will give you the most sub surface scattering possible. In fact, a few tests I did that purposefully generated a scattering_coefficient much higher than 1.0, say 1,000.00, gave the same results as one equal to 1.0, but took a lot longer to render.
I didn't run many tests on the absorption_coefficient, but it is easy to prove that many different combinations of colors and distances will result in computing the same coefficient. For example, plastic's IOR of 1.46 computes to a F0(linear) of 0.035 or a F0(sRGB) of 56/56/56. I assume the log() on the color is done in linear space, so given an sRGB color of 56/56/56 yields a log of -1.456.
If we poke that color, 56/56/56, into our Transmitted Color and set our Transmitted Measurement Distance to 1.456, we'll compute an absorption_coefficient of 1.0, meaning that there is a 100% chance that the light will be absorbed within 1 meter of entering the medium. A different color, 230/230/230, or linear 0.8 would require a much shorter distance of 0.097 to result in a coefficient of 1.0, however it would still mean that there is a 100% chance that the light will be absorbed within 1 meter of entering the medium and the results should be exactly the same as the same Iray VDF is getting exactly the same inputs.
I'm not 100% sure what these mean at this point, but at minimum, we're not directly modifying the things we think we are, or at least what I thought I was modifying. I suppose it is possible that coefficients out side of the ranges of 0.0 to 1.0, or perhaps -1.0 to 1.0, have some special meaning or give different results, but I haven't observed the different results nor have I seen documentation that alludes to that.
I expect that as more information is revealed that we'll be making significant changes to how we setup our Iray materials, :).
EDIT: Added the first Transmitted Measurement Distance value of 1.456 which I omitted originally.
and
Top Coat Thin Film: As I said above if I set the thickness to 100 - 1000 I get some weird colours but if I set it to 100000 I get the gloss colour back to white. So I tried a wax type of colour and got a nice muted wax gloss finish. So what I don't understand is why am I getting some colour change when the thin film is thinner. I know this is in nanometres but I can't work out why the colour shift.

I don't know for sure, but since I'm logged in, I'll take a stab at an explanation, ;-).

I expect it has to do with the relationship between the thickness of the top coat and the wavelength of visible light. This higher frequencies of light, i.e. the blues/violets have wavelengths down to about 380 nm (nanometers). The lower frequencies of light, i.e. the reds have wavelengths up to about 750 nm.

So, if you stay in the range that is close to the wavelengths, you should expect some interaction with the light bouncing around in the top coat. Once your top coat is much thicker, I expect you tend to lose those "weird" colors.

wow thank you even though most of the gloss one went over my head but I liked the wavelength and colour explanation but it does make me wonder what use is it if we can't use top coat thickness for say a clear varnish or wax without this colour wavelength thingy happening.

L'Adair · June 2015

eiliestl said:
Convergence at 100% . Rendered to 7% and timed out after 1 hour and 45 min. Still not that clear. What more can I do?

There are three render settings that control how long Iray will render a scene: Max Samples, Max Time and Rendering Converged Ratio. If any one of the three is reached, rendering stops. By default, Max Time is set to 7200 (seconds,) or 2 hours. You can set it higher, but if you set it to "0" it effectively turns off that setting and will render as long as it needs to reach one of the other two constraints.

Also, if you don't close the image, you can change these settings and resume a render that "finished" too soon.

I generally dial Max Samples to the highest value, Max Time to "0" and Convergence to 100%. As I can stop the render when I think it looks good enough. (I also do a lot of rendering while I'm sleeping.)

Another trick I've learned from the forums is to save the render via the File menu, leaving the render window open. I pause the render, (hitting cancel,) and then go to File>Save last render. This comes in handy if the render is being incorporated into another image. You can make sure it will work as is, and if not, go back and make changes without having to wait until the image has rendered to a high convergence ratio.

I hope you find this information helpful.

zaz777 · June 2015

Szark said:
wow thank you even though most of the gloss one went over my head but I liked the wavelength and colour explanation but it does make me wonder what use is it if we can't use top coat thickness for say a clear varnish or wax without this colour wavelength thingy happening.

You're welcome. Sorry for the late reply, I hadn't noticed your reply until tonight.

As far as top coat goes, yeah, one should be able to get good results like a clear coat/vanish over, say wood or something else with it if you make it thick enough. I've played around with it a bit, but haven't had much luck. The nifty colors you get when you keep the thickness near the wavelengths of visibly light are icing on the cake, :lol:, and actually useful for things like soap bubbles or an oil slick on top of water.

The point I was trying to make on the glossy/reflective topic was mainly that when I try to use other PBR material references/recommendations I've found, I'm finding that it isn't possible to directly use the values they recommend for the glossy/reflective channel in the iray uber material. The other channels map pretty directly to what we have available on the iray uber material shader.

For diffuse, metalicity, bump/normal maps, roughness maps, etc. you can pretty much follow what you find. On the glossy/reflective channel, you'll find that if the material is dielectric (non-metal), you plug in whatever shade of gray from the reference as an sRGB and/or linear color value/range. If it is metal, you'll get a diffuse color, normally black or very dark and an sRGB and/or linear color range/value for the glossy/reflective channel.

So, other, non DS+Iray references I see, give me one number, say 51 to 58 (sRGB) or 0.029 to 0.039 (linear) for skin reflectivity to use as a gray scale color for the glossy/reflective channel. Many times this value actually originates as an IOR and you can use the equations in my original post to convert the IOR to the linear or sRGB color value.

In my understanding, this value actually incorporates the weight of the glossy/reflective layer and how reflective a material is is dependent on the IOR of that material. In the iray uber material, we actually have Glossy Layered Weight, Reflectivity, Glossy Color and Refraction Index (IOR). So, we have 4 inputs to account for what should be one value you'll find in most places, at least the ones I've found.

So, most of my previous discussion on the iray uber material's glossy layer was about how one might make those values (the sRGB and linear colors) work in a way that makes physical sense when one is using that shader.

In the last part of the discussion, the part about transmission and scattering, I was trying to show that for those, there appears to be fairly concrete evidence that some funny business is going on under the covers of the shader. Its likely, or at least possible, that a similar thing is occurring with the glossy layer and that one might be able to ignore a significant number of the parameters while maintaining complete control over the results.

Szark · June 2015

zaz777 After making my reply I went away looking at light wave lengths and the relationship with Nanometres and I am finally understanding what the top coat thickness is for. One article I found was about making a realistic car windshield (windscreen in the UK) and they described the layer between two laminated sheets of glass having a NM of such and such so it was in the blue part of the spectrum. That really hit the message home for me.

I have a feeling that the Glossiness Iray shader is for helping the transition from 3delight, but it is only a guess. I also found that following PBR info doesn't work with the Glossiness Iray shader so I am sticking with the Metal/roughness shader..

Thanks all that has really helped.

Szark · June 2015

I think this image explains light spectrum NM and helps to choose what thickness to make Top Coats to get the colour we want

PS well it isn't so easy as that as I just test it so it would seem it also relies on the IOR of the top coat. Need to do some more digging on this.

SpottedKitty · June 2015

Szark said:
PS well it isn't so easy as that as I just test it so it would seem it also relies on the IOR of the top coat. Need to do some more digging on this.

It does get a bit complicated — the important distance isn't the thickness of the top coat on its own, but the path the light takes through the top coat. If it hits at an angle, the path through is longer than the thickness. This ties into the differences in IoR value as well, since this affects the change in angle when the light hits the surface of the top coat. There's a lot of maths involved if you want to calculate exact values, and it made my head hurt when I brushed the fringes of the subject at school.

Szark · June 2015

LOL My head always hurts with this stuff. Yeah after some more reading I thought it was something like that, glad to know I was heading in the right direction. Thank you

Lagrange · June 2015

I faced a strange problem. I installed Daz 4.8 but iray render didn't appear, there is only old 3delight. I don't understand how it is possible. How to make iray appear?

TJohn · June 2015

helleformer said:
I faced a strange problem. I installed Daz 4.8 but iray render didn't appear, there is only old 3delight. I don't understand how it is possible. How to make iray appear?

You must have installed the 32-bit version. Iray is only in the 64-bit version.

Lagrange · June 2015

Yes, I have an old comp, it's not 64 bit. Dead gommit! So there is no way to get it?

namffuak · June 2015

helleformer said:
Yes, I have an old comp, it's not 64 bit. Dead gommit! So there is no way to get it?

Nvidia only provides a 64-bit version.

dHandle · June 2015

Well, this is definitely interesting.

I just recently got re-interested in Studio, and I’ve been researching Iray. I started reading posts from back in March when the beta was released. I followed Sickleyield’s tutorials on Youtube and DA.

And I tried to reproduce results from settings posted by others. In particular, Ben98120000’s demo using the Level 19 scene. (post #155)

http://www.daz3d.com/forums/discussion/53695/P150

I had a hard time getting his results, so I started fiddling around with the settings on the spherical primitive. I made a default sphere with diameter of 1m and tried to place it in the scene where he placed his. I couldn’t get it right. I tried repositioning it. Nope.

Then I scaled it down and BINGO! It looked very much like his scene. But my settings were a bit different. I chalked that up to changes made from the beta to the full version, but the interesting thing was what I noticed when I rendered out different scale sizes of the sphere primitive.

I of course first rendered it at 100% scale (in the parameters tab) .

Then I scaled it down to 50%, and rendered it, then 25%, then 12.5%, 6.25%, 3.125% and 1.5625%.

Then I tried it at 200% and then WAY down to 0.125%.

There are some differences, of course, but amazingly, the size of the sphere has very little to do with the lighting of the scene.

I didn’t touch the other settings between renders…just the scale.

I rendered the scenes for 4 minutes each, which was only 2-3% and around 400 iterations.

Here are the other settings:

I put Iray uber base on the sphere, and also on everything in the Level 19 scene (Like Sickleyield showed on Youtube). I put the Emissive shader on the sphere, and made sure the headlamp was off. (2 different settings)

Environment: scene only

Emission color: White
Emission Temperature: 2900
Two Sided Light: on
Luminance: 1500
Luminance Units: W (Watts)
Luminous efficacy: 100

As far as I remember, everything else was default settings.

Here are the renders. Sorry if they’re a bit large…

dHandle · June 2015

The last one, I typed in 0.125% by mistake, so the sphere is REALLY small!

Hope this is meaningful. If it's been covered elsewhere, please forgive the repetition.

Like I said, I'm just re-entering the game...

Cheers!

"D"

dHandle · June 2015

Ok..so I relit the scene this morning after thinking about it some more. (3am…don’t you just HATE that!)

I won’t post ALL the partial renders this time (you’re welcome…), but this one may help a few folks. I left the environment mode on scene only, and turned off the primitive sphere. (It was very dark!) Then I went into the Level 19 details, and looked for anything that was labeled some kind of light. Again, like Sickleyield showed on one of her Youtube videos.

I made them emissive. But I noticed something different from SY’s method. I didn’t drop an emissive shader on the lights; I just twirled down the arrow to reveal all the sub-menu items and noticed one of them was labeled “emissive”, so I made the adjustments there.

I changed the “emission color” to white; Emission Temperature: 6500; Luminance: 1500, Luminance units: W (Watts).

I made the consol lights green, lights on the wall red, stairway lights white, and the scene was still really dark. These little lights can’t really illuminate a whole huge space like this.

So, I went looking for ceiling lights. They’re named “Neon”. I played around with Luminance: 50,000, 25,000 and finally settled on 10,000. I like the results! They act like ceiling lights. You can see the dark area in the shadows where the ceiling lights can’t shine under the overhang.

I only rendered the scene for 4 minutes (1%), and about 400 iterations again.

If anyone knows a better or more realistic way to set lights up, please chime in here. I’m making it up as I go…!

Thanks!

“D”

Szark · June 2015

I found the best way to set up lights is to use real world lumen and Kelvin (temp) values and increase Tone Mapping ISO to 1600 or 3200 and drop shutter speed down to say 50 which will let more light in to the camera. Then once you done that add some fill light via Point or mesh lights. Mesh light planes behind the camera works well IMHO.

dHandle · June 2015

Thanks, Szark.

I didn't even attempt to tackle the "camera settings", even though I understand them. Off the top of my head, the default settings seem like they're suited for an outdoor scene in bright or moderate daylight: ISO 100, Aperture F8.0 and shutter speed 1/125. These settings will ensure that most of the scene is in focus, anyway.

I just left all that for another time. Trying to wrap my mind around properly lighting a scene first..at least the technical aspects. I guess my next steps should be trying to light a scene with a "dome", or "dome and scene", or the sun settings.

I think I need to get a good grip on what type of conditions these settings are best suited to. Why would someone chose one setting over another? Would my render have been more realistic if I had used "dome and scene"? It's a completely enclosed indoor scene. Sun settings don't seem to be indicated, unless there are windows (which there aren't in Level 19). Dome settings allow for HDRI images to be used as light sources, right? Again, that would seem to indicate an outdoor scene

I understand I could probably tweak any lighting setup, and make it look decent. I would just rather avoid quick and easy setups that work, and have to unlearn bad habits later.

I'll keep you posted.

"D"

RAMWolff · June 2015

Need help with getting my moon shine set as the scenes light source. I remember doing it once but I can't remember where I set that up where you select the source in the scene to be the main light rather than the default or the headlamp. HELP?

Also, is there at all a way to make something "glow" so I can try to make a moon glow effect or is that something that iRay just can't do just yet??

Tutorial,
Tips,
Help!

Gracias

Szark · June 2015

dhmohr said:
Thanks, Szark.
I didn't even attempt to tackle the "camera settings", even though I understand them. Off the top of my head, the default settings seem like they're suited for an outdoor scene in bright or moderate daylight: ISO 100, Aperture F8.0 and shutter speed 1/250. These settings will ensure that most of the scene is in focus, anyway.

I just left all that for another time. Trying to wrap my mind around properly lighting a scene first..at least the technical aspects. I guess my next steps should be trying to light a scene with a "dome", or "dome and scene", or the sun settings.

I think I need to get a good grip on what type of conditions these settings are best suited to. Why would someone chose one setting over another? Would my render have been more realistic if I had used "dome and scene"? It's a completely enclosed indoor scene. Sun settings don't seem to be indicated, unless there are windows (which there aren't in Level 19). Dome settings allow for HDRI images to be used as light sources, right? Again, that would seem to indicate an outdoor scene

I understand I could probably tweak any lighting setup, and make it look decent. I would just rather avoid quick and easy setups that work, and have to unlearn bad habits later.

I'll keep you posted.

"D"

If the room is totally enclosed the Dome or Sun/Sky isn't going to help. Yeah HDRI in this case wouldn't be any good either.

Here is a scene that uses Scene Only. The background colour you see is just a background colour provided by the Environment Pane > Backdrop > Colour. The candle light is pretty much set up as real world lumen output...almost I had to tweak it a little. The table lamps have the Lumen output of 40 watt GLS (Tungsten filament) lamps. I have two mesh light planes either side, behind the camera to provide some fill light. I had ISO at 3200, F/stop 2.80 and Shutter at 60 and it was still too dark without the fill light. Yes I could have increased the fill light intensity and reduced the Tone Mapping.

I referenced some Photography sites to get an idea what settings are good for what situation.

Szark · June 2015

This scene I didn't use any fill lights at all. I used the Sun/Sky using the Sun Dial to provide the suns position, setting ISO at 1600, f/stop 4 and shutter 50. 10000 samples and Render Quality of 2.00. I didn't render it out fully as it would have taken a day or two. I can only render using CPU.

Szark · June 2015

RAMWolff said:
Need help with getting my moon shine set as the scenes light source. I remember doing it once but I can't remember where I set that up where you select the source in the scene to be the main light rather than the default or the headlamp. HELP?
Also, is there at all a way to make something "glow" so I can try to make a moon glow effect or is that something that iRay just can't do just yet??

Tutorial,
Tips,
Help!

Gracias

Nope no Ambient only in Iray and you never will being a realistic render engine. Glow equals Emission so you need to turn it into a light source. The only trouble I can see is that you will need to really crack up the light output thus destroying any detail the moon has.

To use a mesh light only you will need to set the Render Settings > Environment to Scene Only

mjc1016 · June 2015

Szark said:
I referenced some Photography sites to get an idea what settings are good for what situation.

That is probably one of the best tips around for setting up scene lighting, especially interior scenes.

Szark · June 2015

Thanks it helped me no end. One thing we don't have to worry about at the moment is camera shake so we can use low shutter speeds.

dHandle · June 2015

Szark said: If the room is totally enclosed the Dome or Sun/Sky isn't going to help. Yeah HDRI in this case wouldn't be any good either.

Here is a scene that uses Scene Only. The background colour you see is just a background colour provided by the Environment Pane > Backdrop > Colour. The candle light is pretty much set up as real world lumen output...almost I had to tweak it a little. The table lamps have the Lumen output of 40 watt GLS (Tungsten filament) lamps. I have two mesh light planes either side, behind the camera to provide some fill light. I had ISO at 3200, F/stop 2.80 and Shutter at 60 and it was still too dark without the fill light. Yes I could have increased the fill light intensity and reduced the Tone Mapping.

I referenced some Photography sites to get an idea what settings are good for what situation.

If you were standing in this bedroom when it was lit by those 2 table lamps and a candle, that's probably what you would see. If you photographed it with a fast lens, your photo would probably look very much like this, too. When there isn't a lot of light in the scene to begin with, the image will naturally be dark.

Even so, it's a great "mood" image! Very nice! I would say it's...photo realistic!

You could put a camera on a tripod to reduce shake. This would allow you to use a lower shutter speed, thereby making the image a bit brighter. You could up the ISO a little bit...6400, maybe. That would make it brighter, too. But expect grainy images...especially if you make large prints.

In the 1st image, I notice there is light up high on the ceiling. Is that from the chandeliers?

The 2nd image looks very nice, too! The sun provides a lot of light! It bounces all over the place!

What I know about photography helps me some, but the aperture setting is a bit of a mystery. In a camera, one of the main functions of the aperture settings is to determine the depth of field focus. But from what I understand, the tone mapping in Iray doesn't use it for that. Focusing and depth of field are in the camera settings.

If that's true, what's the aperture setting for? Allowing in more light? To what end? You can already control that twice over with the shutter speed and ISO settings.

There has to be a difference between ISO controlling the light, shutter speed controlling the light, and aperture settings controlling the light in Iray, and what I am used to in photography.

Anyway...very nice renders! Thanks for taking the time to set these up!

"D"

Aala · June 2015

Szark said:
This scene I didn't use any fill lights at all. I used the Sun/Sky using the Sun Dial to provide the suns position, setting ISO at 1600, f/stop 4 and shutter 50. 10000 samples and Render Quality of 2.00. I didn't render it out fully as it would have taken a day or two. I can only render using CPU.

This is really nice! Well done! Shame that you can render with a CPU only. What system do you have?

And if you don't mind me asking, what set is that scene from?

dHandle · June 2015

Here's what I ended up with. I found a few more lights to "turn on", and let it render out a little longer...25 min...about 38%

I added a backdrop too. (Thanks for the suggestion!) I noticed that the backdrop isn't emissive. With the floor as shiny as it is, I would think there would be some orange glow from outside. Have to think about that...

I think I am about ready to put this one to bed, and move on.

"D"

Khory · June 2015

I would think there would be some orange glow from outside.

You know your right. Some of the orange shining through would be logical. Is the glass in the doors Iray?

Szark · June 2015

dhmohr said:
Szark said: If the room is totally enclosed the Dome or Sun/Sky isn't going to help. Yeah HDRI in this case wouldn't be any good either.
Here is a scene that uses Scene Only. The background colour you see is just a background colour provided by the Environment Pane > Backdrop > Colour. The candle light is pretty much set up as real world lumen output...almost I had to tweak it a little. The table lamps have the Lumen output of 40 watt GLS (Tungsten filament) lamps. I have two mesh light planes either side, behind the camera to provide some fill light. I had ISO at 3200, F/stop 2.80 and Shutter at 60 and it was still too dark without the fill light. Yes I could have increased the fill light intensity and reduced the Tone Mapping.

I referenced some Photography sites to get an idea what settings are good for what situation.

If you were standing in this bedroom when it was lit by those 2 table lamps and a candle, that's probably what you would see. If you photographed it with a fast lens, your photo would probably look very much like this, too. When there isn't a lot of light in the scene to begin with, the image will naturally be dark.

Even so, it's a great "mood" image! Very nice! I would say it's...photo realistic!

You could put a camera on a tripod to reduce shake. This would allow you to use a lower shutter speed, thereby making the image a bit brighter. You could up the ISO a little bit...6400, maybe. That would make it brighter, too. But expect grainy images...especially if you make large prints.

In the 1st image, I notice there is light up high on the ceiling. Is that from the chandeliers?

The 2nd image looks very nice, too! The sun provides a lot of light! It bounces all over the place!

What I know about photography helps me some, but the aperture setting is a bit of a mystery. In a camera, one of the main functions of the aperture settings is to determine the depth of field focus. But from what I understand, the tone mapping in Iray doesn't use it for that. Focusing and depth of field are in the camera settings.

If that's true, what's the aperture setting for? Allowing in more light? To what end? You can already control that twice over with the shutter speed and ISO settings.

There has to be a difference between ISO controlling the light, shutter speed controlling the light, and aperture settings controlling the light in Iray, and what I am used to in photography.

Anyway...very nice renders! Thanks for taking the time to set these up!

"D"

Yes there are chandeliers, 3 of them with ten candles each and 4 candles on each end of the room

Aperture Setting: No idea it's there maybe for the future.

Szark · June 2015

atdheshala said:
Szark said:
This scene I didn't use any fill lights at all. I used the Sun/Sky using the Sun Dial to provide the suns position, setting ISO at 1600, f/stop 4 and shutter 50. 10000 samples and Render Quality of 2.00. I didn't render it out fully as it would have taken a day or two. I can only render using CPU.

This is really nice! Well done! Shame that you can render with a CPU only. What system do you have?

And if you don't mind me asking, what set is that scene from?Thanks. PC i7 3770 Quad core, 8 GB of Ram and a lowly GT610 GC.

The scene is http://www.daz3d.com/rosemill-moor and http://www.daz3d.com/rosemill-moor-ii

Szark · June 2015

dhmohr said:
Here's what I ended up with. I found a few more lights to "turn on", and let it render out a little longer...25 min...about 38%
I added a backdrop too. (Thanks for the suggestion!) I noticed that the backdrop isn't emissive. With the floor as shiny as it is, I would think there would be some orange glow from outside. Have to think about that...

I think I am about ready to put this one to bed, and move on.

"D"

No backdrop isn't emissive. I forgot that Level 19 had doors with glass. ;) Even so you wouldn't get much light come in, yes some but not enough to light the whole room.

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