Lighting help

stalmage_e7ed8eaf7a

I've been using DAZ for a couple of months now but I'm still having problems with lighting.  Specifically, when I add a distant light to a scene, the default light setting of 1500 Lumens causes the scene to render washed out--almost completely white.  I have to drop the Lumens to under 5 to get anything usable.  But at that setting, the scene looks dull.

Am I missing something?  I'm using Iray, if that has anything to do with it.

Fishtales

You also have to adjust the camera settings in Tone Mapping for the amount of light in the scene if using Iray. They work on the same principle as a film/digital camera without the noise at high ISO :)

Ostadan

Distant light lux values are different.  They are lumens per square centimeter (because, you know, it doesn't fall off, and hits everything in the scene not in shadow).  Sunlight at noon hits a sea-level target with a flux of 9.8 lumens per square centimeter, so the numbers on distant lights have to be turned _way_ down.

 

evilded777

The really simple answer to your issue is: dont use distant lights.

Distant lights predate most PBR amd they are, in general, not physically accurate, but an attempt to mimic Sun and Sky lights.

Iray's Sun and Sky is a much better option than using Distant Lights, so is HDRI lighting.

stalmage_e7ed8eaf7a

Thanks, all of you!

One question.  When I go to add a light (in the Create menu) I only see four kinds of lights:  distant light, spotlight, point light, and linear point light.  Are Iray's lights found in a different place?

mjc1016

There are no 'Iray' lights...

Those 4 are the basic lights and what settings are exposed depend on which renderer is being used.

 

stalmage_e7ed8eaf7a

So then where do I find the Sun and Sky lights?

Renomista

stalmage_e7ed8eaf7a said:

So then where do I find the Sun and Sky lights?

In The render Setting under Environment. By Default the oprion is on Dome and Scene, Change that to Sun Sky Only.

Please note that normal Lights (e.g. Spot Lights) doies not work in this modus.

But Mesh-Lights (Surfaces with Light Emission) do. So You can replace a Spot lights by a Plane primitive with an emissive surface

 

stalmage_e7ed8eaf7a

Thanks!  I got the dome lighting to work but I need more lights to illuminate corners and soften and add shadows.  However, I'm having a hard time figuring out how to make an emissive surface work.  I've found some tutorials on it but I don't see any results in my renders.  I've tried both planes and spheres, even using Iray shader presets on them but to no avail.  Is there something I'm missing?

stalmage_e7ed8eaf7a

Slight correction:  There does seem to be some slight influence from the plane, but only on a couple of textures (in my case, hair and eyes).  The surface has no effect on the rest of the face or body.

stalmage_e7ed8eaf7a

I bought some additional light presets and tried them out, but I got the same result--no effect on the scene.  In fact, to verify this I changed the Iray render settings to Scene Only to turn off the "sun".  At this point, my scene is black.

However, I noticed something--when I'm using the Iray drawstyle and move any of the light presets, the subject lights up briefly as I would expect and then goes completely black.  Is there some setting that might be causing this--something that sucks the light out of the scene?

Renomista

You wont see the effect of the emissiv surfaces in the texture shader preview, only in the render.

if you dont see it there you probably need to push up the luminacy

Fishtales

It does sound as if your Tone Mapping settings are wrong for the amount of light in the scene. The settings are adjusted like a camera to get more or less light into the lens of the DAZ Studio camera.

stalmage_e7ed8eaf7a

Renomista said:

You wont see the effect of the emissiv surfaces in the texture shader preview, only in the render.

if you dont see it there you probably need to push up the luminacy

I did a test render but it had the same effect--the subject was black.  I'll try more luminacy.

Fishtales said:

It does sound as if your Tone Mapping settings are wrong for the amount of light in the scene. The settings are adjusted like a camera to get more or less light into the lens of the DAZ Studio camera.

I'll give the tone mapping settings a try too.

Thanks!

SpottedKitty

The tone mapping settings are especially important since the default values are just right for an outdoors bright sunny day — that's what the default Iray environment light is. If you have an indoor scene, or the light level is brighter or dimmer than "sunny day", then your render will look terrible. It's very much a juggling act; you must balance the amount of light in your scene with the amount of "light sensitivity" of the camera.

SickleYield

Hi!  I've done three tutorials that cover this exact thing!

 

stalmage_e7ed8eaf7a

Thanks, everyone!

I finally figured out what I was doing wrong.  I wasn't properly applying the emission preset to the primitive.  Even though I had selected the surface tab on the primitive, I ended up having to double click twice on the preset (yes, two double clicks) to get it to take.  (This is from the content library and not the Presets tab.  For some reason, almost nothing I have in my library shows up under the Presets tab.)  Once I did that, it started having an effect on the scene.  Then I learned about cd vs. kcd and just how much luminance you need to get a primitive that's not near a subject to actually light them up.

Problem solved.