I've noticed that every now and then my renders end up with these lighter pixels spread around certain surfaces. Usually hairs, but this has happened with other things like Clothes too.
I thought this could be renders finishing too early, but that doesn't seem to be the case, the render above, for example, converged way before any of the hard cutoffs (time or samples) from the settings. Do people usually up the convergence ratio to above 95%?
What causes these noises? How can I reduce the occurrence of these?
Thanks for any kind of assistance
Edit:
Increasing the convergence ratio to 98% (from the default 95%), greatly reduces this problem.
But I was wondering if there are other things to address that could solve this issue.
No idea of the cause, however, a lot of hair resources have this problem. I used to suggest reducing the subsurface scattering however, I've not found a better way (from
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).
Selecting each surface for the hair and under Geometry select a value of 0.98 for cut-out opacity That's worked for me with issues I've had with hair causing random bright bits.
No idea of the cause, however, a lot of hair resources have this problem. I used to suggest reducing the subsurface scattering however, I've not found a better way (from
You must be registered to see the links
).
Selecting each surface for the hair and under Geometry select a value of 0.98 for cut-out opacity That's worked for me with issues I've had with hair causing random bright bits.
Sakrilas - What kind of spotlights are you using? If your spotlights are set to "point" instead of, say, "rectangle," this can contribute to this as well. True point lights pretty much don't exist in nature - most real lights have some "area" to them. This cuts way down on "fireflies," because each pixel gets illuminated from a variety of different angles, even if those angles are small. Point lights tend to generate very hard shadows, and also artificial point reflections.
Sakrilas - What kind of spotlights are you using? If your spotlights are set to "point" instead of, say, "rectangle," this can contribute to this as well. True point lights pretty much don't exist in nature - most real lights have some "area" to them. This cuts way down on "fireflies," because each pixel gets illuminated from a variety of different angles, even if those angles are small. Point lights tend to generate very hard shadows, and also artificial point reflections.
I feel like I should do a course of lights and cameras, because this has to be my weakest link at the moment.
I get amazed with the work of other render artists out here, like the ones by SilkandMilkProductions.
Until a week ago, my lights where always a combination of simply assigning an HDRI and use the Emissives from the scene itself. For closed spaces I would rely on culling out part of the scene behind the camera to let the HDRI poke through to the characters. Sometimes I would even create my own emissives by making a primitive shape and changing the surface properties of it.
This one over here is an example of that:
Inside her fitting room booth, I added 3 emissive cylinders at the roof with a warm light colour, just to make it easier for the player to see Casey's front.
Recently I started to use Ghost lights and I've been loving it. This scene below uses HDRI for the most part and 2 weak ghost lights to fill it a bit more with light.
I never really relied on setting up "point" or "rectangle" lights. Should I be employing these rectangle lights often then?
I would really love to sit down and go over a multiple hours course to be able to move a bit in the right direction with lights.
Do you or anyone here have any suggestions for a course? Paid or not, I would be very interested in checking it out.
Until a week ago, my lights where always a combination of simply assigning an HDRI and use the Emissives from the scene itself. For closed spaces I would rely on culling out part of the scene behind the camera to let the HDRI poke through to the characters. Sometimes I would even create my own emissives by making a primitive shape and changing the surface properties of it.
This one over here is an example of that: View attachment 1290719
Inside her fitting room booth, I added 3 emissive cylinders at the roof with a warm light colour, just to make it easier for the player to see Casey's front.
Recently I started to use Ghost lights and I've been loving it. This scene below uses HDRI for the most part and 2 weak ghost lights to fill it a bit more with light.
I never really relied on setting up "point" or "rectangle" lights. Should I be employing these rectangle lights often then?
I would really love to sit down and go over a multiple hours course to be able to move a bit in the right direction with lights.
Do you or anyone here have any suggestions for a course? Paid or not, I would be very interested in checking it out.
I found this to be a pretty helpful tutorial for some nice ways to setup interior lighting, which tends to be more complex than exteriors where you can rely more heavily on HDRIs. The only issue I had was that he doesn't really cover strong character lighting, more just environment lighting, but I find that's a good first step in the process.
Start by turning any surface lights that might have come with your environment props off or down very low, so your scene is very dark. Then, light your environment with one or two large spherical point lights and/or ghost lights. Then brighten up faces or whatever you want to be the focus of your shot with a large disc spotlight or two. If you want more highlights (shine off the skin, glint in the eyes, etc), use smaller, stronger spotlights targeting the areas where you want those effects. Lastly, add back-in any visible lights in your shot by turning back up the surface lights for only the areas where you can see a particular light source, just so it looks like they're on, or you could fake them with spot renders and photoshop.
That's been the general process I've been using lately and has produced much better results than trying to start with prop lighting or cut out walls and use HDRIs as the primary interior light source.
I never really relied on setting up "point" or "rectangle" lights. Should I be employing these rectangle lights often then?
I would really love to sit down and go over a multiple hours course to be able to move a bit in the right direction with lights.
There is no "one size fits all" approach to lighting, of course. I'm far from an expert, but I've learned a thing or two so I'll just tell you a few things I know.
Ghost lights are awesome for situations where you have to get light in, and there's no way to do it without the spotlight being visible. A ghost light is simply an emissive surface (usually a plane) that has had its opacity dialed down very, VERY low so that it doesn't render as anything.
There are, IMHO, two disadvantages of ghost lights:
Because they are non-directional, if you use a large one, they tend to wash out any shadows. The result is that your scene can look "flat." This can be somewhat counteracted by keeping them smaller in size.
They result in scenes that can be much slower to render than scenes that use only HDRI's and spotlights. The reason for this is that iRay "understands" spotlights, and knows that it has to pay attention to them when rendering a scene. Emissive surfaces, on the other hand, iRay just kind of "discovers" as it throws rays around the screen. As a result, scenes with emissive surfaces tend to converge more slowly than scenes without them.
So, I almost always start lighting a scene with spotlights rather than with ghost lights, and use them only as a last resort.
A few tricks:
If I'm lighting an interior, one way to do it is to put several large spotlights in a rectangular array just under the ceiling. By "large", I mean setting them as rectangles with their width and height set to maybe 100x100. Set their "angle" (which defaults to 60 degrees) to maybe 120 so that the light spreads well. Unless the ceiling is very low, this will typically give good area lighting from "character head down". It won't, however, usually light faces well, but then...
I almost almost always have a spotlight-per-character in the scene, which I face so that it illuminates the part of the character I want lit. (usually their face, but sometimes the back of their head if they're facing away from me). These are also rectangles. The larger the rectangle, the less in the way of sharp shadows it casts, of course. So, for a closeup where I want some shadows to enhance the 3D effect, I'll typically use something like 20x20 or 40x40. If it's an outdoor scene, or a scene in a large, well-lit room (like, say, a store), then I'll go more like 100x100.
Here's an example of the combination of the two of those. Two large rectangular lights pointing down from above with (I think) 150 angle, then a spotlight per character (off-screen left and right) pointing at each character. I was careful with the one lighting Melanie to not cast a shadow on the wall, since all the lighting is supposed to be from above (the way it would be in a house) and the spots are just to create some "fill" to reduce the shadowing on the faces. (One problem with this shot is that the walls are white. If I had it to do over again, I've have set the house up with non-white walls, since that would make the characters stand out better. Oh well.)
Other items:
You definitely want shadows. Even if they're subtle. That's what makes the characters look 3D. If you look closely around the room you're in, you'll see there are lots of subtle shadows. So, you don't want illumination from directly in line with the camera. As a result, I almost always have my spots offset to the left and right of the camera, even if they're pointing at a character who's directly in front of the camera. This is sort of 2/3 of the classic "three point lighting." (The third light would be a "rim" light from behind the subject. A lot of times it's hard to get that light in there, but having the "key" and "fill" lights gets you a long way.
In this one, the hallway is illuminated with those overhead spots I mentioned, and then there's a key and fill light on either side of the camera pointing at the character. (You can see them reflected in his eyes.)
Of course, sometimes the optimum position for a spotlight tends to put it in the field of view of the camera. This can particularly be the case if you're using large rectangular spotlights - corners might peep into view.
If the required spotlight is facing toward the camera (unusual, but sometimes...) or if its reflection shows in a mirror or something, then you really don't have much in the way of alternatives - you really have to go with a ghost light.
If, however, the spotlight is casting its light in the same direction as the camera and the problem is just getting rid of that black rectangle that shows up as the back of the spotlight, you can hide the back of the spotlight by turning off the "Render Emitter" setting in the spotlight. (Why that isn't the default I'll never know. Why would you ever WANT that black rectangle in your scene?)
Finally, there are times you want a darker scene. Iray does poorly with dimly-lit scenes. So, instead of turning down the lighting, what you can do is to light the scene more or less normally, so that iRay has plenty of light to work with, and then adjust the exposure level under "Tone Mapping". (Diddle with "Exposure Value," "Shutter Speed" or "F/Stop" - it doesn't really matter which one, as they're all interconnected.)
This scene had a normal daytime HDRI, for example, but was then darkened that way. I then put a (very bright) downward-facing spotlight at the top of the lamppost.
Anyway, those are a few of my tricks. So, I do use ghost lights when I must, but spotlights tend to be my go-to tool, since I can usually make the do just about anything that ghost lights or emissives can except in VERY tight quarters, and I've found that I get better shadowing and faster rendering with spots.
I'll certainly check out this tutorial you shared, dynamix.
Both of you made me realize that I shouldn't be relying on the emissives of the scene. I must say it's pretty daunting to see how many things we'll have to keep in mind in regards to the lights for the render.
But I'm sure with practice this will become second nature eventually.
Your explanation about emissives vs spotlights, Rich, also made me understand why I have renders that take 3 hours and still don't end up with a high quality in the details at the end. Thanks for showing me your thought process too. I'll be referring to this thread for reference.
I need to spend some time playing around.
Just out of curiosity, does any of you (or anyone else reading this thread) make use of helper scripts to make setting up these spotlights easier?
I've seen this helper tool here
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And I have a thing for Riversoft Art, a lot of their scripts are amazing at making life easier. I was wondering if you would have any suggestions for other tools that would help setting up spotlights for the scene.
Just out of curiosity, does any of you (or anyone else reading this thread) make use of helper scripts to make setting up these spotlights easier?
I've seen this helper tool here
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And I have a thing for Riversoft Art, a lot of their scripts are amazing at making life easier. I was wondering if you would have any suggestions for other tools that would help setting up spotlights for the scene.
I looked at the description of that script. While it might certainly help some people, I don't think I'd use it. Given that you can "look through" spotlights just the way you can look through cameras, positioning a spotlight to point directly at a certain target is (at least to me) absurdly simple. When I'm doing overhead lighting, I'll set the spotlights to point directly down using their rotation dials, and then position them using the "Top View". When I'm setting up figure spots, I'll just create a spotlight (usually telling it to position it where the current view is), twiddle with the parameters, and then use the "look through it" to position it where I think I want it in the screen. Pretty easy peasy.
Note - some of Riversoft Art's scripts ARE awesome, I'm just not drawn to this particular one.
I just want to say thanks again for all the suggestions and tips. Specially you, Rich , for taking so much of your time to explain things in detail to me.
I'm still learning, but last weekend I went over 2 courses of lighting techniques.
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where she teaches best prectices for 3-point lighting, and the one recommended by dynamix911. I'm still just scratching the surface and playing around with the dials, but at least now the idea of manually posing spotlights or point lights around looks way less intimidating than it was a few days ago.
You know... it even made me like rendering even more fun. This here is a render where I tried putting some spotlights lights around.
Using the 20x20, 40x40 to make shadows harsher and 100x100 for soft shadows is being an amazing rule of thumb too.
I just wanted to chime in back to give a progress report and show my appreciation. You guys are great.
That's a nice render. Among other things, it REALLY illustrates the "rim" light effect of the 3-point lighting. (The "glow" around her hair and on her left shoulder.) I don't tend to use rim lights, partly because many Daz hairs don't deal with it well. (No surprise - hair is VERY hard to make work realistically in all ways.)
For the general public, a few other things I didn't specifically mention in my earlier wall of text:
Positioning a light so that you get a nice reflection off the eye (particularly with closeups) is another one of those subtle things that can make a render look more photorealistic. This figure is probably a bit too far away for that effect - no worries.
One thing that I see a lot in renders is situations in which figures are back-lit. Darker figure, brighter background. In some cases, that's an effect that you want, but those are less common. If you want your figure to stand out, you generally want it lit somewhat brighter than the background. Combining this with Depth of Field is a great way of directing the viewer's eye, since the eye is automatically drawn to the parts that are brighter and in more focus. This render does a pretty good job of illustrating that - note how the figure is subtly brighter than the background, and the effective use of depth of field to separate the figure from the camera in the foreground, and from the background.
One thing that I might have tried, if this was a render of mine, would be to add some external light coming in through the window. The outside is bright during the day. Even if the window is on the shady side of the house, you still get a lot of ambient light coming in windows. So, I'm seeing bright sky, yet there doesn't seem to be much external light hitting the curtains through the window. It'd be interesting to see the effect of a directional light or a big spotlight outside the house casting light through the windows onto the curtains. (Possibly this could also be attacked by rotating the HDRI outside.) You'd get some shadowing from the window sashes onto the curtains, etc. which would be a subtle, but realistic-looking, effect. (Of course, it also might fail miserably - that does happen with experiments.)
Another thing that might be considered is the fact that the computer screen is a light source. For a small laptop in a bright room, it's a pretty minor effect. But if she was closer to a bigger screen or in a darker room, it's a definite contribution.
Of course, when you're banging out renders for a game, you usually can't afford to be a perfectionist about them. You can't spend days fine-tuning a single render that your readers are going to look at for all of, maybe, 10 seconds. But every now and then I take a single render and use it as a workbench for "let's try some techniques."
But, at the end of the day, when doing lighting, the best advice is "Think about how light works. Look around you - critically. Focus on where light is coming from, and where shadows are being cast. At the end of the day, shadows are as much your friends as lights."
FYI, here's an illustration of where I made a monitor cast light. (Granted, it's probably too much light for the relatively dark web page, but I used the same setup for a series of images, some of which were brighter.) In this case, the monitor image is emissive. That's necessary to make it look realistic since monitors do, after all, emit light. But there's also a ghost light positioned just in front of the monitor to cast light on his face. I liked the effect.
This scene has an HRDI outside that both provides the background for through the window, but also casts light onto the window frame. As you can guess from the directional shadows being thrown by the monitor and the chair, there's then an overhead light (downward-pointing spotlight with a wide angle and large area) that's simulating the room light up on the ceiling.
If the room had been darker, I'd have probably changed the temperature of the ghost light to 9000 degrees instead of 6500. That would make the light onto the face be slightly blue-ish, which gives a kind of "artificial light" effect. Low temperature lights - maybe 4500-5000 - are more red-orange. Great for, say, firelight scenes. High temperature lights are more blue - they're good for night scenes or other artificial light sources. 6500 is pretty close to "sunlight."
One more option, I don't know if it was specified but increasing the Rendering Quality does help with those spots in the hair. Test it, with small resolution, you will see that a higher Rendering Quality setting will get rid of more of those spots, but at a cost, slower.
One more option, I don't know if it was specified but increasing the Rendering Quality does help with those spots in the hair. Test it, with small resolution, you will see that a higher Rendering Quality setting will get rid of more of those spots, but at a cost, slower.
Not that one imho. They did a slight change in opacity layer (around when they introduced PBRSkin iirc, not sure if it is from shader brick they 'cleaned'/updated or from an Iray update tho), problem is exacerbated in older OOT hair custom shader. Putting opacity at .99 should fix it.
There is no "one size fits all" approach to lighting, of course. I'm far from an expert, but I've learned a thing or two so I'll just tell you a few things I know.
...
A few tricks:
If I'm lighting an interior, one way to do it is to put several large spotlights in a rectangular array just under the ceiling. By "large", I mean setting them as rectangles with their width and height set to maybe 100x100. Set their "angle" (which defaults to 60 degrees) to maybe 120 so that the light spreads well. Unless the ceiling is very low, this will typically give good area lighting from "character head down". It won't, however, usually light faces well, but then...
Rich this is really helpful, thanks. A couple of follow-up questions to the above.
- How far away to you typically space these spotlights?
- How many of these spotlights do you find yourself using in a "standard" rectangular array?
- Is there a ratio you use for the luminance of these spotlights vs the luminance of the character focused spotlight?
Rich this is really helpful, thanks. A couple of follow-up questions to the above.
- How far away to you typically space these spotlights?
- How many of these spotlights do you find yourself using in a "standard" rectangular array?
- Is there a ratio you use for the luminance of these spotlights vs the luminance of the character focused spotlight?
TL;DR: I recommend looking into environment lighting, following that with basic lighting techniques (three point lighting, side lighting, rembrandt, etc.), and then cinematic lighting tutorials. Regular lighting tutorials can mostly be applied to Daz with a bit of experimentation.
Holy necro lol. Not Rich, but I think I can drop my two cents here. This isn't exactly an ideal way to light a scene, or interior, though I suppose the definition of 'ideal' changes within context. As he said, this isn't ideal for faces. Spotlights are basically exactly for that, lighting up the characters/figures.
That being said, what I often find myself doing is lighting an interior by turning off the environment lights and then replacing them with a ghost light. It's basically what I do
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and
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. Both of which are using older Ghost Light assets that no longer work with newer versions. SY Invisilights Iray is basically the same the same thing. What do after inserting those ghost lights is accent the lighting created them with spotlights. Always safer to start a little dimmer with the ghost lights and you want the accent of spotlight to show up.
That is to say that there's a difference between environment/indoor lighting and character/figure/object lighting. One isn't exclusive to the other, hence what I wrote above. Context of a scene and how it's lit are important to deliver mood. For example:
This render is done with an HDRI (which is minimal in regard to the lighting here, only illuminating the window sill closest to the left.), two spotlights and a ghost light for the painting in the background. The idea here is that the spotlight is acting in place of the sun to illuminate the figure. In three-point lighting, this would be called a key light. It's your main light source in most traditional uses. The rim light is often exactly how it sounds. It's creating a rim of light behind the figure, as you can see on his shoulder and hair here.
Of course, this isn't the only way of lighting characters. If you're in a darker scene, say at a restaurant or diner or something a bit darker, using primitive lighting can be super easy. I find using cylinders and scaling them down on the proper axis (axi?) until they're the shape of Quasar tube lights to work best. This is actually a pretty common indie technique.
Daz spotlights are quite easy to understand once you understand how lighting works.
The bigger the spotlight is, the softer the light's edges will often be. So, if you go 100x100 with a rectangle geometry on the spotlight with 50000 lumens, you might get something like the left. But if you drop that 100x100 to something like 50x50, you'll get something closer to the right. I'm aware they're two different examples, but they working under the same fundamental concepts of bigger vs smaller spotlights.
So, working under that same concept, how does a rim light work? If the bigger spotlight carries softer edges, the smaller spotlight will then obviously carry the harsher edges. Like you can see in the above post. The best advice I can give is to watch lights. See how they work and interact with the world, with whatever their environment is. See what the lighting does at different angles. Each style of light is going to do different things, but that doesn't mean they have to be fundamentally used in the same way for every picture, video, or render. Three-point lighting could basically be all you ever use and every render could still look great. It's just about how you apply them.
Apologize for the book, if this wasn't what you were after and would still like to hear Rich's advice (completely understandable, honestly.), just thought I'd throw my two cents in. May help someone else, so I'll just leave it lol.
For indoor scenes I use a ghostlight slightly smaller and lower than the ceiling to light up the whole room.
This is the base light of the scene.
If there are windows, put a big ghostlight or spotlight outside for the sun.
Lamps in the scene provide extra pools of light, don't rely on them to light up the whole room.
These are my accent lights.
Finally, I put a half-cylinder or half-sphere ghostlight around the character in focus, angled to simulate the perceived main light (the sun from the window or a lamp shining on the character).
This would be my key light I guess.
I find that this setup is sufficient for the most part, extra lights can be placed if needed.
Here I used the ceiling light, outside sun and half cylinder.
Here I used a HDRI with low intensity for the background light outside, and a ceiling light for the indoor part.
The lamp on the balcony provides a little accent and a half-sphere simulates that on the man.
If I tried to only use the light from the lamp to light up the man, the rest of the balcony would be way too bright.
This is the same setup, only the half-sphere is re-positioned, because the woman is standing between the lamp and the man.
I fell out of the habit of using ghost lights primarily because iRay handles spotlights far more efficiently than emissive surfaces. In many cases, I found that using a large spotlight with a large "spread" value gave me visible results that were very similar to using ghost lights (as long as the light was not in the camera's field of view) but rendered much more quickly on the rig I had at the time.
In addition, too extensive use of ghost lights can give you a very "flat" looking render, without the shadows that (to me) make things look more "3d."
That's NOT to say that they're bad - used correctly they can be very effective. They just weren't my own personal go-to tool, unless I really needed an invisible light because it was in the camera's FOV.
Rich this is really helpful, thanks. A couple of follow-up questions to the above.
- How far away to you typically space these spotlights?
- How many of these spotlights do you find yourself using in a "standard" rectangular array?
- Is there a ratio you use for the luminance of these spotlights vs the luminance of the character focused spotlight?
It depends on the environment, of course. I tend to use rectangular lights that are 100x100 (1 meter square) with, as I said, a 120 or 150 spread. I usually have a gap of a few meters between lights. For a hallway, I'd probably have one line of them down the middle of the ceiling. For a locker room or living room or something like that, maybe a 2x2 or 3x3 array of them, depending on the size of the space. I usually adjust the luminance of the spotlights so that the background is lit to the level that I want.
That being said, what MissFortune said about faces is exactly correct - this won't give you good lighting on the faces of people in the room - this is for background lighting, so the room isn't dark. I will then typically have a couple of spotlights that illuminate the characters themselves. Otherwise, you have the problem of their faces being somewhat shadowed by the overhead lights.
As to the ratio of overhead to character, that's all "eyeball calibrated," based on where I want the viewer's eye drawn. Frequently, I'll dim down the background just a bit when I'm doing a close-up of a character so that the aren't "backlit."
Bottom line - there are lots of different approaches. Sometimes it's just as easy to remove the ceiling and let exterior HDRI's be your background lighting. The techniques mentioned above are all good too.
