Added my own JPG texture, but lights wont work on it
heisdave
Posts: 130
I am am working with a daz asset for an in interior room. I changed the texture for a plain wall and made it a brick wall. Now I am trying to light it with areas of light and shadow for a render in Iray. When I create a spotlight and point it right at the wall, the wall remains dark. When I render in Iray, the spotlight does light the area, but only when I put the light RIGHT up against the wall. A distant light wil llight the wall but I cant get the effect I want with a distantlight. Is there some extra step you need take when adding your own textures to get them to work properly??
Thanks!
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a quick guess is you don't have your spotlight turned up high enough
Yes, you have to use very high values, like Intensity 100.000 or more.
But I wonder how a distant light can light up the wall, as they generally don't work in Iray. Is dome light turned on?
If the interior room is completely enclosed, then the dome light can't get to it. You can also adjust the spread angle of a spotlight to cover more area, but this may defeat the purpose of having a spotlight in the first place. A mesh light might help.
>>Yes, you have to use very high values, like Intensity 100.000 or more.
the intensity of the spotlight only goes up to 200% , which is where I have it set. or do i need to change the range?
yes if i make the spread range extremely wide, it will start to light the wall, but in a uniform way that defeats the purpose
Chances are very good you are working with the Iray render engine. Assuming that's the case, changing the "intensity" of the spotlight won't affect anything, as that is a 3Delight setting. You need to increase the Lumens, the second to the last parameter of the spotlight. Start off with something high, like 50,000.
Both Intensity and Lumen works, you just have to turn off limits for Intensity in Iray to use the values necessary (e.g. 100.000). The Lumen value is confusing as it doesn't match real life values at all (1600 Lumen compares to a 100 W bulb), it's pretty odd that you have to use 10.000 - 3.000.000+ Lumen for a spotlight, depending on distance and spread angle, to get a decent light. What the reason is for this I don't know.
The series in this post of mine started with a spotlight at 1500 Lumen. I also use a Distant Light a lot when I want the sun from a particular angle which is usually set between 10000 and 50000 Lumen. I have no problem lighting an image using these settings.
https://www.daz3d.com/forums/discussion/comment/2898646/#Comment_2898646
If you scroll down there are a few more posts adding and removing different lights.
I've always read that Intensity was a setting for the lights in 3Delight. This is the first time I've seen it said it works in Iray as well, if you turn off limits and crank it way up. As the saying goes, you learn something new every day!
I agree, too, that it seems really odd that the lumens necessary for a spotlight or distant light need to be cranked up so high.
The Intensity setting when used in Iray increases the Lumen by the percentage chosen i.e. 1500 Lumen at 500% is 1500x5 = 7500 Lumen. Using the Lumen setting and leaving the Intensity at 100% gives you a more accurate light as you can then set any Lumen value you want to get the light you need. So if 1500 isn't enough it can be set at 1560 (example only :) ), or if it is too bright then set it at 1490. You wont get that amount of accuracy using Intensity.
I guess it was originally, when DS had only 3DL. The reason it also works in Iray is probably because it's the same thing, just with different parameter scaling. It looks like the Intensity/Lumen ratio is about 1:10 in numbers (e.g. Intensity 100% = Lumen 1000).
As for distant light, only Intensity works AFAICS, Lumen does not have any effect at all. And it does't not work inside closed environments, just like the Iray dome.
Well like I said earlier the effective light ratio between Intensity and Lumen seems to be 1:10 so yes, you can fine tune Lumen more precisely by a factor of 10. But in practice it seems irrelevant as a difference of +/-10 is hardly noticable because of the high resolution of the Lumen scale in DS. With Intensity set at 100% for example, I need to set Lumen at 2.000.000 for the spotlight to get a decent light in this room:
Lumens work. You just have to crank 'em way up there. As I didn't realize intensity had any effect with Photometric lights, I've always used Lumens when using a Distant Light.
I wouldn't use a spotlight to light a room. It is used to throw light on a specific thing within the room the rest of the light would be ambient light using other lighting methods.
As I already said I use Distant Lights a lot as sunlight and rarely go above 50,000 Lumen. The distant light isn't for interiors so if you want to use it you would need to remove a wall or the ceiling to let it in. You can use the Iray Dome in interiors using Finite Dome and scaling it to fit inside the room and turning Draw Dome off and only using it as lighting.
These two images use one Spotlight set at 10,000 Lumen as I wanted the shadow sharp against the far wall. The second image has a Volume Cube to try and get a God Ray effect. The Environment is set to Scene Only so no other light is being used.
Hm, yes, you're right. Must have done something wrong when I tested it the first time (no light even a 1.000.000.000 Lumen). Probably had set Intensity at 0 or less. Maybe they should have hidden that Intensity control in Iray to avoid any confusion and just let it remain at 100%, it seems that you can do fine with Lumen alone.
Hm, how do you scale the dome to the correct size? I've tried to set Radius to 1, but no light, and can't see what I'm doing. The dome center is per default world center, right?
Sorry it should be Finite Box. When you choose that and scroll down you will see three sliders for Width, Height and Depth, you use these to scale the box to fit inside the room.
@Taoz
FWIW, I've never had to use a lumen value approaching even 1,000,000 to light a scene. Values between 300,000 and 500,000 are the highest I have needed. There is also no significant penalty to using geometry settngs on sportlights and more than one spotlight in a scene (within reason.
Just to point out also. Using the Finite Box inside the building wont light it but will give some ambient light to add to any added lights.
The first image below is the Finite Box Enlarged so you can see what it should look like and the light that is coming through the windows from it.
The second image is the box shrunk to fit inside the room.
The third image is the box settings.
The fourth image is what I got using the HDRI I had already open which is the light image, the low res one not the background one, for Alexs_Apartment. I have shut off the glass so that there is no light coming through from the outside.
OK, not sure what geometry settings are though? And I actually have two spotlights in the room in the renders I posted, just turned one of them off to show the Lumen value needed for one light (which is less of course if you use several).
As for the Lumen values as such I don't care so much about what they need to be to work, though it would be smarter if they were lower (lower resolution). What I'm complaining about is that they're totally out of sync with Lumen in real life.
Thanks. So it's ambient ligh - that explains why the render looked so weird when I finally got this to work. Does the box have to be the same size as the room, just a bit smaller? I found it very hard to see what I was doing, making the room partly transparent helped seeing the box, but still. A script that would automatically do all the work would be handy, and probably not hard to make.
The lumen value for lights in Daz is actually not that far off from real world values, but you have to adjust the Tone Mapping values in the render settings to appropriate values for your scene.
Think if the Iray engine as a completely manual camera that is by default set for bright outdoor scenes. If you take that camera indoors without adjusting the exposure controls first, and then try to take a picture with it, the resultant picture will be very dark.
The "Tone mapping" settings are the exposure controls of the Iray engine. http://docs.daz3d.com/doku.php/public/software/dazstudio/4/referenceguide/interface/panes/render_settings/engine/nvidia_iray/tone_mapping/start#white_point
The attached render is of a Gen8 female in a completely enclosed 3m x 3m room with a single point light in the center of the room at a height of +- 2.5 m. The lumen for the point light is set to 800 (more or less the same as a 60w bulb).
I attached a picture of the Tone Mapping settings I used for the scene. In this case I adjusted the ISO value to get close and then tweaked the "Exposure Value" setting.
Note that I did not adjust the materials for the "walls". The walls are just planes with the default material so they are slightly reflective, hence the second dim shadow behind the character.
@Taoz "OK, not sure what geometry settings are though"
You can change te geometry of a spotlight in the Parameters>Light>Geometry tab. The atached shot shows a spotlight that will act like a 100cm disc softbox.
Ah, OK, yes that makes sense. Thanks!
Oh, OK, was actually playing with these settings yesterday to see what happened, but the name "geometry" just didn't ring a bell. Thanks!
Just one (IMHO major) flaw with the light geometry settings — you can't see in the Viewport what shape and size you've just set up. Something for the next D|S version, maybe?
You can if the viewport is set to Iray and show emmiter is on.
Ah, yes that's right. I hardly ever think of that, because my current system crawls through displaying the Viewport (or Aux.) in Iray, so I never use it.