Lights, Reality4, a growing need to drink heavily...
Stryder87
Posts: 899
Hi everyone
I’m trying to render a scene and am really hitting a wall. It’s an inside scene with 5 lights: 2 are table lamps from the ‘InaneGlory's Lights and Lamps 1 - Table Lamps’ package. The other 3 are flat panel mesh lights, one as the main ceiling light and the other 2 as fill lights. When I go to do some rough renders in DAZ, they look not too bad, I just need to fix the lighting strengths (the table lamps work fine and the 3 mesh lights work). However, I bought and would really like to use Reality4 as everyone seems to rave about it. I’m running into a number of issues (now that I have actually had a chance to try it). I'm not sure if it's an issue with the latest release, although I did do another scene with it before and it worked.
The scene consists of ‘Luxury Bedroom Scene’, two G2F, misc props and the lights mentioned above.
1 – When DAZ/Reality transfers the scene and I go into the Lights tab in Reality, the two table lights aren’t even listed.
2 - When it transfers the scene and I go into the Lights tab, the three mesh lights are listed and checked, there is one IBL that is not checked (again, the two table lights aren’t even listed). When I adjust the Wattage and Efficiency of the mesh lights, then go to do the render, the scene loading fails in Luxrender with the error that there are no lights present.
3 – If I check the IBL along with the mesh lights the scene will load and start to render. Here’s the problem now; the table lights aren’t even lights, just static props, the mesh lights aren’t working (or at least aren't noticeable)and the scene is being flooded and overpowered by light coming through the missing wall of the bedroom, washing out a lot of the scene. I have no other light sources so I don’t know where this ‘other’ light is coming from (IBL?).
This is really becoming disheartening as I just want to create but the technical aspects of all this, especially lights, is just killing me.
Can anyone make some suggestions? I’m really lost here. None of it makes sense. I've tried reading posts about lighting and such, but it gets so technical it just makes me glaze over.
Thanks.
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Comments
The table lamps will need you, probably to select (in Reality) the material zone that is best suited to the task (hopefully a bulb material zone) and convert it to a light (right-click and select 'Convert to Light'). In general DS lights are not copied directly across as the difference between how DS handles light and how physics works means it is not worth the effort of redoing them.
When you say 'mesh lights' are these UberArea lights? If so, you'll need to convert those to lights that Reality/LuxRender will recognise as mentioned above.
What SimonJM said, never use DS specific lights with Reality. Only use the Reality lights or create/use simple mesh objects to convert into lights in the reality panel. You will need to know/understand about how light actually works to get the best results with unbiased rendering. If you have a lamp of any type, make sure there is a bulb object that you will turn into a light once you open the Reality panel
While I didn't get a chance last night to try out your suggestions, I did give it a quick testing before heading to work this morning.
I loaded the scene as usual, sent it to Reality and then checked the Lights tab. The 3 AreaLight Plane mesh lights I had in the scene were there (see attached screenshot) as usual. I went into the Materials tab and added the two lamps, right-clicking on the 'Bulb' object associated with the lamps and converted them to Lights. They then showed up in the lights tab as seen in the screenshot. I left the AreaLights as they were to test with first. A quick partial render in Luz and the table lamps were working! The AreaLight ones weren't though. So, doing the same as you suggested with them, even though they were already in the Lights tab, I converted them to lights as well and did another quick test render. They were now working, too, albeit too strong and a LOT colder than when rendered in DAZ itself. I need to figure out how to adjust that. My DAZ test renders are a lot warmer and darker in comparison.
You guys are awesome! :coolsmile: I'm always amazed at how helpful people are on this forum. Many many thanks.
Now another question... is there a way to adjust the light strengths 'on the fly' as Lux is doing the render so you can see the results in real time? I can't find anything in the different tabs or other adjustment areas, and making adjustments in Reality don't transfer across once Lux is up and doing it's thing.
Thanks again for the help guys!
You can change light settings inside Luxrender itself once the render gets going. I'm at work so I can't tell you the exact location but there is a light tab or something obvious inside the Luxrender window that you can adjust the settings with. On the next refresh you'll see the changes. VERY handy feature.
Once Luxrender starts changes made in Reality aren't applied unless you quit Luxrender and start the render again from Reality. I'm quite a novice at Luxrender myself but when the stars align it's just amazing what you can get from it.
I saw an area dealing with Mesh Lights, but there didn't seem to be anything in there to actually adjust the individual lights. It looked like they were all lumped in together without a lot of options.
I'm going to see if I can find a manual for Lux on their web site. Sometimes vendors have good ones, sometimes they don't. I usually find I learn better just jumping in and trying stuff out, but this is all starting to drag on and be a downer. I want to get this stuff going here while I still have all these ideas in my head for what I want to do! ;-)
In luxrender, there is a light groups tab next to the render tab, all your light info is there. You can adjust the intensity, add some warmth or change the color on the fly. For more precise options depending on the light, look under the light tab in the reality panel (see image). Click a light and more options will show under it.
You don't adjust lights as such, you adjust 'light groups'. The fewer light groups you have the more efficiently the lighting is performed so having a group per light (if you have oodles of lights) is probably not a good idea. Your lights will, generally, fall into similar camps, so all lamps which would be the same could be one group, etc. To (re)define what group a light is in select the light and in the 'Light Properties' section overtype the Light Group.
Ok, but if I needed to adjust, say, just the 'fill' lights, yet they are all grouped together, how would I do this? To adjust them in Reality won't transfer over unless I stop the render and restart it, just to see if a small change was good enough. That could get really time consuming.
In the example I'm working on, I have 5 lights, 2 of which are what I consider 'fill' (the character wall ones), 2 which are environment/mood (table lamps) and the one main one (ceiling). Having 3 groups (main, fill, mood) would probably be fine for this scene, as I could at least adjust the major groups individually in Lux on the fly.
One quick question: if you have a light 'pointing' at a certain area, does that transfer over into Reality/Luxrender? I read that doing something like this can 'lock' the light source onto only that object (which I would think could work well if it's a fill light) and not affect surrounding objects.
It will depend on how the material zones and geometry pan out, but if you can see each of those lights as separate items listed then give the one(s) you wish to fine tune a different group name.
Light in LuxRender acts as light does in real life, you cannot constrain it's effects, such as limiting a light source to only illuminating one item.
I wrote up a short tutorial that might assist you with "pointing lights" in Reality.
http://jasongalterio.deviantart.com/art/Reality-Light-Viewport-Tutorial-514630566
Essentially what you want to do is add the Reality light to your scene. Then create a camera. Parent the Reality light to the camera. Go into the Reality Light's parameter settings and set translation & rotation to 0.
Now you can direct the camera viewport and the light will follow.
Awesome tips! I'll give these a go tonight!
Parent a light to a camera... didn't know that was possible. Genius!
Also, another trick you can try...
Set each light to its own group, but set the render size as relatively small. As small as you can get and still be able to do a test render.
In Luxrender, fiddle with the intensity of each light until you are happy with the results. Make note of the general relationship of the light intensities to each other. In other words, get a general proportion of each light intensity.
Close Luxrender and go back to Reality. Change all of the lights so that they are in the same light group. Set the intensities to the general proportion you were happy with. Increase the render resolution to your desired level.
The result should be a much quicker render while preserving the general relationship between the lights, without having to have a large number of light groups.
It was an "ah ha!" moment for me a couple of weeks ago. It didn't even occur to me to try.
After setting up the rig, you can take a look at it from a different perspective and fine tune it. For instance, I know that the Curved Light is fixed above the camera, almost light a traditional flash. So you can lower it down a little bit fairly easy.
The Mesh Light is the same way, but also blocks the view port. So you can lower it down and back a bit to make it function properly.
After I set up these two rigs, I saved them as Scene Subsets in my custom Library directory. That way I can add them with just a click.
So I managed to spend some good quality time working on my scene last night. Had some interesting results. I think I now really understand what Unbiased means. To me it seems that the lights you put in are as true to life as you can get, with only warmth (colour) and intensity the real settings. I was wanting to turn off shadows on a fill light and there was no setting for that in Lux like there is in 3dDelight. To get around that I'll need to split that fill light into 2 or 3 smaller ones positioned around the problem object. That's going to be a lot of fiddling. :-S
However, even after 8 hours of render time in Lux, the picture wasn't anywhere near done as there were still some pretty glaring artifacts, and it was obvious that the lighting was going to have to change. I did love being able to adjust light strength and warmth on the fly. I wish you could do that with 3dDelight.
One issue I'm not sure about: the table lamps. I had them set to 25Watts, 5 Efficiency, but you could still clearly see the light bulb through the shade, even though the shade was set to 95% opacity strength. Maybe I'll need to bump it up to 99% Opacity, drop the wattage to about 15 (although 25 was really nice) and make the efficiency around 2. Learning that as I go.
The biggest annoyance was transferring from Reality to Lux. I added an extra light to brighten a face, and Lux never saw it (plus I had to redo the Convert to Light part on the other lights again). I tried reloading Daz, Reality and Lux a couple of times but it wouldn't 'reload' the information into Lux properly. I tracked down about 3 places Lux was saving it's scene information and deleted it all, then it seemed to finally see the new light properly. Is there a simple way to force Lux reload from Reality??
I suspect this scene, being indoors, will be a lighting nightmare for me and me limited knowledge on how this stuff works, so I may be better off doing this one in 3dDelight and the outdoor scenes I'm planning I can do in Reality. Or maybe there is an indoor Uber2 light setup I could use to take care of some of the fill in lighting that would work well in Reality/Lux?
One other thing I found: some of the skin textures really have that 'waxy' look I read about. I found this: "At SSS scale 4.0, a lot more light travels into the object. More than 1, tend to give you more of that wax like look." If this is true and would help make the skin look more 'real', would you adjust this in Daz, Reality or Lux (not that I saw this setting Lux anyway)?
Oh, and turning on Noise Correction in Lux made for some very very weird 'haloing'-type effects on objects, particularly skin. An SSS thing (not that I really understand how SubSurface Scatter works anyway). :question::question:
tldr haha
edit - I forgot to add... When I added an extra light, Daz automatically added a Headlight Blocker. It seemed to stop the new light from working until I deleted it. What is this and why does it get put in?
Glad you are getting a better understanding. I personally never use DS lighting, which I view as a good thing as I don't have to switch mentality from a biased, to unbiased way of thinking. You having a want to turn off some shadows is a perfect example as that isn't an option in unbiased rendering. The bigger the light source, the softer the shadows though.
On the lamp, try raising the opacity on the shade and change it to matte translucent or just use a bulb shaped object, I have used both methods depending on the scene and the lamp used.
On skin, I strip everything but the actual main textures out in DS and then adjust settings in the reality panel, less confusing that way.
I never use noise correction, tried it a few times and never got good results.
Not sure what you're referring to here. I'll have a look when I get home, but I'm not sure what you are stripping out. Something from in the character itself or settings on the surface (skin)?
Man there's a lot to all this!! haha
Two thoughts...
One, you shouldn't have a headlight blocker if working with Reality / Luxrender. Headlight blockers are for special lights that DS doesn't consider lights. If you have no DS recognizable lights in the scene, when you render, DS will automatically add a light. The headlight blocker blocks this light. So while DS thinks there is no lights in the scene, the non-light still emits, as well as the default hidden light that DS adds.
Two, something that not every one agrees with... If you force Luxrender lights to do things they shouldn't, Luxrender tends to "break."
What I mean is, if you make Luxrender lights be way too bright then they have a right to be, the render goes berserk with artifacts. This can happen if you are trying to get light to flow into areas of the scene where it wouldn't normally go.
Try to approach the lights like a photographer would. Position them as if you were really taking a picture. Place reflectors to get light to flow into spots that direct light doesn't go. Always try to use multiple light sources, one light source will almost always cause harsh effects.
(And multiple light sources isn't the same as multiple light groups.)
I'm not familiar with reflectors in Daz. Is that a Daz thing or Reality/Lux? Where do I find those. I dabble with photography, so I'm familiar with reflectors, I just didn't know they existed in Daz(or I just didn't recognize what it was if I saw it). That would be a lot better (quality-wise) than trying to use a straight light source and neuter it down to simulate reflected light.
Reflectors don't exist as stand alone props. They can be any prop and are actually defined by the material settings. The material settings will reflect or absorb the light just like in reality. So if you keep that in mind when you are setting up the scene, you can achieve the results without any extra work.
One of the things I always suggest to beginners is to try not to add extra lights. Instead try to use an indoor scene prop. And try to use the surfaces that make sense as light emitters. Lamp bulbs and the like.
The light fixtures in these props tend to be positioned as they would be in reality. And in reality they are positioned there for a reason. That makes them perfect for understanding the nuances of intensity and such.