A (hopefully) simple light question.
Usually when I light an interior scene I just put spotlights all over the place to light it, because they're easy for a foolish person like me to understand; just point them at what you want lit. But I have a lot of scenes that have square light panels on the cieling (space ship corridor for example), and I'm sure there must be a quick and simple light I could use for them to project light. I tried using UberAreaLight plane, and in the viewport it lit things just fine. but when I render it doesn't seem to light anything and I have a glowing plane floating there. Also it loads with AreaLight Headlamp blocker, no idea what that is. I'm not looking for anything photorealistic or resource heavy, just a quick simple way to add ceiling lights.
Any suggestions, guys?
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Comments
Iray or 3dl?
I use 3DL.
I often use the UberAreaLight shader on the lighting surfaces, but you do need to crank it up a little, and I also try to remember to activate fall off an dincrease (can't recall the option/parameter!) to 32 or more to prevent 'blotching' Best used with other sources of light to even things out (a direct light with shadows set off is useful for that). Could also continue to use spots, but increase spread angle to 120 degrees or more.
I selected the light panels and then clicked UberAreaLight Base in the lights tab in smart content, but couldn't see any change in the viewport, and the render was just black.
The UberAreaLight shader does not emit light in the preview pane and you do need to crank it up a little, if using for an overhand light for example I'd probably start at around 25,000 for intensity (and don't forget to turn on drop-oiff, and set to (I think) squared)
The panels now emit light, and I've made falloff active, there's all falloff start, end and decay. Any idea what kind of setting they should have? I'm just messing with things at the moment.
Unless you have a specific need I'd leave the falloff start and end as default, is it dceay that can be linear, inverse square, etc., if so the inverse square one will provide natural falloff/decay.
The headlamp blocker does just that, it prevents the camera head light from illuminating the scene when the only light source is the area light shader. It has no impact on the final render.
If you activate fall off and leave the start/end at 0 and leave decay at default 2 (inverse square root), the light will behave in a realistic manner. Remember to activate shadows and crank up samples to 64 or more to get rid of noise. And, as Simon mentioned, add atleast a zero or two to the intensitiy, as a starting point. Also, for a more realistic effect, insert the panel diffuse map into the ambient color slot and set ambient on, for a glowing effect. To make the light the right color, insert the same map into (light)color.
I've almost got the result I want. However on decay all I see is a slider bar, no options for linear, inverse square and so on. Am I looking in the wrong place? And although the square lights are now lighting the scene, the squares themselves are not glowing like a light would, although ambient is set to 100. Thanks for the info so far.
Thanks also, I'll try these and see what happens.
Another quick question, what does "crank up samples" mean and how would I do that?
With the light panel selected, in the surface editor tab there is a samples channel, the default is 8, which is very low, and will result in grainy shadows. 64 is a good starting point.
The ambient channel only makes the panel glow, it doesn't affect the light being emitted. Intensity will control the emitted light intensity. Color will control the emitted light color.
Use Ambient coloor (set to 100% probably) and to a color and/or map which mathes eitehr the diffuse or lighting color to make it look lie it is glowing.
In surface editor I have pixel sample ( x and Y) set at 4 and shadow samples set at 16. And I still can't get the light panels to glow although ambient is at 100.
No that has to be the render settings you're looking at now...the area light shader settings are found in the surface editor tab.
Check the ambient color...set it to pure white and it will glow.
Found the samples setting you mentioned where you said it would be (a case of me being blind there) and changed that to 64. Altered ambient to pure white as well. I'll see how it goes.
I usually make the ambient colour roughly the same as emissive colour so the colour of th elight is similar to the colour of the glow.
Ambient is at 100, pure white, diffuse and colour map and everything all match, but still won't glow when rendering whilst using uberlight shader.
Iguess it comes down to what you mean by glow, then - if it's the appearance of a 'blutrred nimbus' around the light source then you'll have to do something else to achieve that: you might do it with a bit of 'atmospherics' near/around the light, or by doing something in postwork.
You might want to try an intensity of 10000 if the diffuse maps are very dark, which can be the case with light panels. Also note that you can turn off limits for ambient strength, and set it to 200 or more.
Looking at this now, am I imagining it or did the omUberBaseLight used to have a drop down wheer you could select the type of dropoff as well as the decay setting?
Not that I'm aware of. Fall off is simply controlled by fall off decay in the surface tab. A number of 2 (the default) equals the physically correct fall off, while a number of 0 equals no fall off. The start- and end values can be used to limit the light spread, to speed up rendering, but is not physically correct:)
A quick play with it: using 100% for Ambient in all 3, makign sure I set Ambnient Active to On first (omUberAreaLight seems to set it Off by default, when applied), 1st with 100$ Intensity and 32 Samples, 2nd with 250% Intensity and same samples, last one with 250% intensity and 64 for samples.
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I think Ambient Active was where I was going wrong, didn't realize it needed to be turned on.
Also, is it my imaginaton or does increasing the sample number greatly increase the render time?
Yes, increasing sample number does increase render time, but it does, markedly, improve the quality of the render: you will get a feel for what you need in association with otehr lighting.
Increased render time for a single image is fine, but for a comic strip with several panels it's going to take a quite a while. As I'm not going for photo-realistic what settings would be best with the lighting to get a decent, but fairly speedy result? If that's possible?
From memory it can depend on what other light sources you have - you'll need to experiment I am afraid. By all means use the default (low) value to get an idea of the light and shadows you get, then crank it up to a point where you are hapy with teh additional quality and yet not tearing your hair out over render time. I'm a programmer so I tend to do multiples of 2, but I usually start at 16 or 32 and see how they play out, but I generally do not do comic strips with the need for a rapit turnround. The blotchiness you can get from the UberAreaLights on surfaces where the light shines can be lessened by more samples but also by other lights being active in that portion of the scene. Have a play and get a feel for what you need and want and like.
Cheers for the info guys, there's always new stuff to learn with DS. I'll have a mess around with the settings and lights and see what happens.
If speed is important, don't use the area light shader, just the DS default shader with ambient strength at 100. Place spotlights just under the light bulbs/fixtures, with a spread of 180 or a little less, adjust light falloff -color and -strength. Note that the falloff ratio of the standard DS spots is adjusted in parameter/light. A value of 0.02 equals physically correct behaviour, IIRC. The standard lights samples are controlled in render settings/samples. You also could use the dz shader spotlights (library/light presets/dz lights). Their samples can be set independently for each light, sample settings are in (with the light selected) parameters/light, and the render sample settings are overridden. Finally, if you own the AoA lights, use them! Render the fastest and have many advanced options to speed up rendering.
Thanks, I'll take your advice and only use the area light shader when I have more time. For speed I'll use your suggestions thanks.