Issues with lighting and Reality 2.5
Passero
Posts: 32
I am using Reality 2.5 and LuxRender to render my images and I cannot seem to get the lighting right.
I have an outdoor seen so I added a sun.
When I render the scene I get an efficiency of just over 100% which seems a bit on the low side for a bright day...
When I add a diffuser to get rid of the hard shadows from the sun, the efficiency drops to around 90% and my model is somewhat grainy while the rest of the scene (which is not affected by the diffuser is fine).
After that I tried adding a softbox but I have to crank up the setting to make it affect.
If I change the power to something large like 4k watt my scene isn't affected although the softbox is really close to my subject.
Only when I change the gain to 10 I see something change in my scene and I get an efficiency of 103%.
I attached an image of the scene that I am trying to render.
The current image has a sun, diffuser and 2 softboxes and both softboxes have a gain of 10 and power output of 4k and efficiency of 57 lumen/watt.
Any pointers on this?
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How long are you letting the render run for? What is the S/px value when you are finished with the render?
You do know that Luxrender doesn't stop rendering until you tell it to, and that overnight renders are common with Luxrender?
Yesterday I had about 200S/px. I know, not enough but I stopped it because everything else in my scene was nicely rendered without much grain. Except for the model. She was still grainy and because it was running at below 100% efficiency I thought it would never get better.
It's because I read that if the efficiency is not high enough, LuxRender doesn't find enough light and you might end up with grainy renders.
I am starting out with Reality and LuxRender and I am scarred I will loose a whole day rendering and and end up with grainy renders :)
I haven't used Reality or Luxrender for a long time.
If you wait for a while, I'm sure that someone will be along who can help out more with this. In the meantime, you could try just rendering the face of the character to see if it will eventually clear. Save your Scene as it is, start a new Scene, and merge your saved scene into it, and move the Camera forward (or change the focal length) to see if that helps any. It should render a lot quicker, and you may get to 2000 S/px in a couple of hours or less.
Hi yannic :) I've been rendering mostly with Reality for about 2 years now so hopefully I can help :-P
You've mentioned the efficiency and s/px value, both of which seem to be on the very low side :-S What are your film response, ISO, shutter, and f-stop values? I'll be able to better figure things out that way.
As a rule of thumb "less is more" when it comes to using lights in Reality, even for a daylight exterior scene. People have different preferences; I've come to prefer using sIBL for the key and a mesh or softbox for fill and/or eyelight, depending.
It's a pity the site that hosts the Reality forums is down till the 25th or I'd refer you there; I'll do what I can to help in the meantime ;-)
Welcome to your new obsession :lol: %-P
Thanks.
I initially wanted to post this on the Reality forum but as you stated, I noticed it was closed...
My camera in DS has no presets for ISO, shutter and f-stop.
In LuxRender when I use the linear kernel it picks following settings:
ISO 50, 1/1000 and f/5.6
I am also a keen photographer so I understand these settings are normally used in a very well lit environment so I don't really understand why I get an efficiency of around 90 or just about 100%.
Currently my evironment is setup as you described. I have a sun and a softbox to softer the shadows.
Attached is the progress in my render so far.
370 S/px - 55 kS/s - 117% Eff
It's been rendering for over 2 hours so far.
It's great that you have a background in photography; that's a big advantage when it come to Reality/Lux :cheese: I've trained and worked as a cinematographer, back when celluloid was still being used :P
The camera film settings are done in Reality, not Daz; you'll still need Daz to set the focus if you want a shallow dof, though ;-P
RL camera settings aren't always the equivalent in Reality/Lux; it took me some time to wrap my head around that :red:
From what I see, the first and second scenes have good key/fill ratio although they are rather grainy. Graininess is caused by "light starvation" as Paolo would put it. A quick and easy fix (and this may seem counter-intuitive) is to tweak the settings while rendering. That's one of the advantages of LuxRender: you can do that without ruining the render. When the image seems overexposed as you open up the ISO, don't panic; you can tweak down again when you get rid of the graininess.
I just checked a previous render which is also a daylight exterior scene, it's eff is 107%; daylight exteriors tend to have low efficiency because the light travels a long distance before bouncing back to the lens. Low efficiency is not always a bad thing just as high efficiency is not always good (like when a scene is overlight and the RAM usage goes through the roof :shut: )
My suggestion, like JimmyC's is to create as safety file (and don't forget to change the file name and output in Reality!) , render in Lux and tweak the settings as it renders. By way of comparison my daylight exterior settings are:
Film Response: Agfacolor Vista 800 (doesn't over saturate the colors; kodak favors reds and yellows and fuji blues and greens, like in rl %-P )
ISO: 1250
Shutter: 1/8
f-stop: 2
In the safety render, I suggest tweaking the ISO up while bringing the Shutter and f-stop down. While rendering you can have it a bit overexposed and bring it down later by stopping down and/or tweaking the gain (both of which can be done during rendering as well).
I think bringing up the ISO and bringing down the shutter/f-stop should help with the exposure/graininess.
By the way, the eyes look a little cloudy; try setting the material to Glass, removing all the maps, check "Architectural", set Index of refraction at 1.04, move the thin film thickness and thin film IOR to 0 and set opacity to 1.0. You should get better results.
THanks for the tip.
I didn't know I could tweak the gain from my lighting while rendering. This is great. I lost so much time in stopping my render and just tweaking the light gain... Doh.
Increasing the ISO seems counter intuitive to get rid of grain...
I just set the ISO to 400, f/16 and 1/1000 shutter.
I don't see much difference when it comes to grain.
I am currently at 570 S/px
Will the grain go away if I let it render to up to 1000 S/px or won't it get better?
It's strange that only my model is grainy. If you look at the background, especially the leaves in the water, they already look crisp to me.
Thanks for the eye tip. I will try this out on a different render cycle :)
You're very welcome. It's a learning process; I don't remember how long it was before I realized that I could tweak the settings during rendering :-P
I don't think the grain will go away, not with your current settings (I've had renders that have reached 25K-30K s/px :lol: and yes, they were daylight exteriors). Tweaking the ISO in Lux is adjusting the lighting in fine increments; while it may seem like a lot, bringing the ISO from 50 to 400 won't appreciably change the light starvation, especially since you've stopped down from f/5.6 to f/16. Any light that would have come through by upping the ISO would have been negated by the "aperture" getting smaller.
Conceivably those settings could work if you let it render to 5k. Alternatively, let more light in during the render and when the grain disappears stop down.
Beginners ask is there any way to speed up the rendering time, the short answer is "no", if you want a good render. The long answer is "yes but only if you use network rendering" but that's another story :P
See if I get this right...
During rendering I should crank up the ISO to something like 800 or higher?
After it has been rendering for a while I can stop it down to a normal value like 200 and this would solve the grainy pictures?
If not, I don't think I understand how to solve the grain.
I will speed up the process later, I have 3 high end laptops that I will configure as my personal LuxRender farm ;)
My recommendation is to bring up the ISO and lower the f/stop. Most likely it will look overexposed. That will actually address the graininess because now the image is getting enough light. Or you can just lower the f/stop till the hot spots look 1-2 stops overexposed. Let it bake till it looks good then you can tweak the settings.
I hope all of this this makes sense :)
And it's great that you have the hardware for a render farm; that will cut down the render time :cheese: I use 4 machines with i7 processors and the 32 core total is a huge help %-P
Thanks for all the help and useful info.
I learned a lot from this thread :)
I stopped the rendering after a little over 5 hours 30 minutes and got just below 1000 S/px.
For the last 90 or so minutes I followed your advise and let it capture light in a slightly overexposed setting.
I didn't really know that those settings would change the actual render. I thought they were just for visual inspection of the rendering. Because of this, it makes much more sense to play with these settings during rendering.
Here's the result and I am actually quite pleased with it. It's so much better than the rendered from Daz3D itself :)
I'll start another rendering in bit and will keep the advice in mind. I will also try to get better eyes.
Do you have any tips to increase the realism on the skin? I seem to notice that Reality 2.5 doesn't do a good job in translating the skin material from Victoria 6 (or any 6 model) to Lux so I guess I need to do some tweaking there as well.
W00t :-) That's pretty good :cheese:
It's a PITA the site's down; there are threads on the best settings for hair and eyes in Reality :-S Hair is one of the big issues; there are Do's that work and a number that don't :shut:
Thanks for the watch, btw ;-)
Reality does skin well, actually: this article really helped. But in addition to that, make sure to use specular maps; that's when I started seeing the "poetry of flesh" :)
This is Michael 6 HD with Gen 6 skin; at that point I still hadn't gotten the hang of the eyes :down:
holy.... This is really nice.
Is this the default skin or did you apply a different skin? I don't seem to get similar details in my Victoria 6 skin. WHen I render it seems plastic and without much tone differences.
I still have a lot to learn ;)
Thankies much for the kind words :) I still consider myself a n00b; it's a journey, not a destination :-)
It's the skin that comes with Michael 6 HD. It's all about settings, though. I actually do prefer the earlier skins (I use the M4/V4 Auto converter plug-ins).
What is key is making sure that the skins (no matter what generation) have a photo-sourced base, vendors do mention that. Getting the settings right is also key, the ArtXtreme interview has a very good range for glossiness. Most vendors will also include specular maps, which is key for making skin look alive :)
On the other end of the spectrum, giving skin a high gloss is good when you want it to look artificial :lol:
Did I also mention I am also a noob with Daz3D? :D
If I load my model (Victoria 6 or any other), will it have a proper skin or do I need to tweak it?
Currently I don't actually tweak the material. I just assume when I load the model it has a proper skin material loaded...
It's not so much about the character having the proper skin as it is having the best settings :)
When you invoke Reality 2.5 the "materials" tab is highlighted; this is where the settings are tweaked. It can be a PITA to calibrate but this is where the magic happens :lol:
Selecting the "Owner" column arranges everything according to the "asset" it belongs to. Most of the time the settings will be too high. Choosing the right settings and applying different maps may seem daunting at first but it does become easier with experience ;-)
This is my second render using LuxRender and first using Reality 2.5 (I prefer Reality over Luxus...at this point).
I used default settings with "Lela for Victoria 4 and Genesis 2" on the SubSurface Mat for the skin and just tweaked the clothing all to Matte in Reality and rendered with 1 RealityLight-Curved....this cooked for 19h36m (I started it and went to bed and work the next day).
I was amazed at the outcome! I am sooooo looking forward to actually understanding how to 'use' Reality to make my renders as I envision them in my head!
Based on your render using "Michael 6 HD with Gen 6 skin" 'bandit' I want to try out an M6 render next. These types of threads are awesome, thanks I learn a lot from the members of this community.
(hard to see the skin results on the render without seeing in full size)
I'm sry if im in the wrong form, but I didn't know where else to turn. iv'e ben playing with daz3d now for about two years ive gotten a lot better since I first started but i'm nowhere near where I want to be. with that being said here is my problem, I would render an image in daz and come up with these kinda results the I saw WOW there is something that could make it look more real that's when I bought reality 2 and that's where I started to get stuck. first I could not find where the image was @ then I didn't know how long I was supposed to let it render for one time I let it render for 24hrs and it looked like my render in daz was better looking then in lux. so I try to google to see if they could help with lighting or how to get a nice looking image from start to finish like what to do in daz then what to do in lux before rendering I had no luck im not good with all the terms they use for tweaking so I was hopping someone could pls help me I don't what a softbox is or if it would help or mesh lighting but I here it a lot and I don't know how to use, I just double click on sunlight and call it a day lol my computer in a hp AMD Athlon 64x2 Dual-Core Processor 4200+ 4gig ram 320GB Nvidia GeForce 8200LE graphic im not sure what this means but I hope it helps
Hi.
A couple of notes, which I hope will help.
Don't get stuck with efficiency, I never look at that number.
First make sure that you are using the Linear tonemapper. If you use the autolinear you will not be able to adjust the lights to your liking, since Lux will automatically adjust the exposure.
Cranking the gain up is perfectly OK, the sun is much brighter than the standard mesh light. You can also use mesh lights only or a combination of IBL and mesh lights. No need to use the sun for outdoors.
Hope this helps.
I also been using it for over 2 years if I add lighting to the sun it will increase time. I don't need to. I usually balance the Sun and sky lights
Reality forums are back online, finally :lol: These forums are great but you'll get faster responses there, I promise ;-P It's also where Reality users hang out :P
@sloth_xvx sorry for the delay in responding :red: I love what you did; it's wonderful use of chiaroscuro :-)
@ducenickels The sun will give you a very harsh light. A softbox and meshlight creates even and diffused lighting; think of it as a beauty light :cheese: In the Michael HD example a meshlight provides the key (main light) and a plane is placed behind the figure and converted to a light to provide a soft back light ;-) I used the same technique for my forum AV but with a stronger backlight and less powerful key :)