Frustrated with IRAY and lights
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MOVED THIS QUESTION TO DAZ STUDIO FORUM. NOT SURE HOW TO DELETE IT. SORRY.
I am very frustrated with DAZ Studio and its treatment of lights for IRAY. First of all, there is no relation between the preview and how the render will look. None. Second of all, it seems hard to even get lights to show up at all in many cases. I must be doing something wrong because no one else is complaining about it. Can someone tell me what render settings are required so that basic lights actually light a scene? I already chose (Scene or Dome and Scene lighting),
Please help,
Keith
Post edited by keithml on
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To move a topic to another forum, click on the gear icon on your original post, click edit and then change the category from the drop down list at left of the page. Please do not post another copy in a different forum, as this means people can be duplicating the effort whilst trying to help you
Thanks.
Chohole. OK, now I know how to move it. Is there a way to delete it?
By the way, I am still in need of help with Lights under IRAY. Please see the top post.
I actually merged them, having seen 2 posts with the same title, before I realised what they said. You can edit them yourself, you just can't delete them. In fact Moderators don't actually delete anything, we just collect it in a hidden area.
I can't actually help, as I use Bryce.
Your initial post doesn't describe much in the way of how you are attempting to light the scene or whether you are just starting out with IRay or have some experience.
If it is the former, you might like to watch SickleYield's tutorial to get you started. I had big problems at first with guessing luminance settings but you get used to that eventually. Also look at some products to make the setup easier - Ghost Lights by Kindred Arts and, perhaps, Painters Lights ... both available in the store and there are threads in the forum about how to use them.
Thanks marble. Originally I was using the helper light setups and it works quite well. The problem is when I use the basic lights in DAZ, there doesn't seem to be a relation to the actual lighting and the preview. Also, the lights need a huge luminance boost and with position based lights, much closer proximity, to get results. Point lights seem particularly problematic. Take a simple room with no lights. Put a point light in and a person. Set the environment to scene only. I just don't get the results I would expect and the preview display is of no help at all in light placement. Is there a best setup for a case where I am going to use the basic lights in a dark room? What is the best way to preview the results. Are their products with better basic lights (point, spotlight, etc) for Iray?
Thanks,
Keith
DS viewport only recognises certain types of lights (I think Photometric Lights only but I may be wrong). So the scene in the viewport will not show you the lighting if you are using mesh lights such as the Ghost Lights I mentioned. When I say viewport, I'm talking about the OpenGL preview, not the IRay preview which I try to avoid because it hammers my GPU.
So you have to do a test render to get an idea with IRay. I do test renders rather than the IRay preview. Other things to remember - the camera headlight is often on by default so that might spoil whatever you are trying to achieve with (photometric) point lights or spots. Also, you can try switching off the viewport Scene Lights (CTRL-L) - that will show you what the scene looks like with just photometric lighting (or it will be dark if there are no photometric lights).
The luminance settings for the built-in light types (Distant, Spot, and Point) are based on real-world values, though it may not appear that way. Lumens is a measurement of visible light emitted by a source of a particular geometery, but in a scene you're really dealing with overall incident light. Spot lights can focus their lumens in a specific direction, for X lumens will appear to be a brighter light on the subject than from a Point light, which casts in a 360 degree sphere. With all the lumens going everywhere, there's less to shine on any particular surface in your scene.
Unless you take into account all the variables involved, you're better off just ignoring the actual values and not try to replicate the real world. Know that a spot light of about 15000 lumens at a distance of 10-12 feet will do a modest job lighting a single character.
Some ideas, in no particular order:
A) Point lights are not for lighting a person, unless the person is some globular sphere and you put the point inside it. Reserve point lights for casting overall illumination in a scene, as ambience, or to beam out some light from a lamp prop in your scene.
B) Forget distant lights unless you want the sharp shadow. Good for something like sunlight streaming through a framed pane window, where you want to cast a "gobo" shadow from the panes. Otherwise too harsh for most things.
C) Rely on an HDRi for general ambient light. This only works if there's your set doesn't have a ceiling that will block the light.
D) Ignore Preview Lights except as a gross indication of placement. Only Iray knows the strength and quality of the lights, and this occurs only at render time after making significant calculations. Though slow, you might have some success using the NVIDIA viewport preview, which is a real time rendering that approximates (but does not 100% duplicate) what you'll get in a full render. The NVIDIA option is there with the other scene view options: Wire Frame, Shaded, and so on.
E) If you know photography, best advice I can give is FORGET most everying, and use the knowledge only as a guiding principle, not the steady rulebook you may be used to. Iray is not a camera, despite the camera-like controls.
THanks marble and Tobor. Great advice.
D) Ignore Preview Lights except as a gross indication of placement. Only Iray knows the strength and quality of the lights, and this occurs only at render time after making significant calculations. Though slow, you might have some success using the NVIDIA viewport preview, which is a real time rendering that approximates (but does not 100% duplicate) what you'll get in a full render. The NVIDIA option is there with the other scene view options: Wire Frame, Shaded, and so on.
I always turn off the headlamp of the camera; you don't have control over its light and it becomes a bit comfusing.
You do have control over the headlamp, both intensity and position. It can be useful, but I agree it's often easier to just turn it off and use a specific light. It's a bit wacky under Iray: internally, camera headlamps are said to be D|S distant lights, but they aren't Iray distant lights -- too many differences in the light quality. They appear to have more in common, beam spread and shadow detail, with a directional point light.