ArchViz - 1000 lights?

[mike_verta]

Seasoned, grizzled veterans lend me your ears...

I have an archviz which will include animating chase light bulbs on signs in an amusement park. You'll be able to see the bulbs clearly, including the filaments inside. Wondering how best to approach this in VRay so it's both realistic, but renderable. If the lights were distant, I could cheat the chase patterns with animated self-illumination maps - I've done this before. But in this case, I'm wondering about what the actual light sources will be, and where to delineate the actual geometry from whatever's actually casting the light. There's no hiding in this one. The animation of the chase patterns might possibly be scriptable... not sure. But first up is handling a thousand actual glass light bulbs with visible glowing filaments...

Thoughts? Ideas? All welcome and appreciated!

[sirio76]

Vray can deal with thousand of lights without issue since the introduction of the adaptive lighting, in your case I would use a self illumination material for the filament (with no GI) and an invisible spherical light to get faster lighting.

[Morbid Angel]

I did something like that a few times. Its not that difficult actually, you just have to be strategic about how you begin, for example few things I would consider:
- model the bulb to whichever fullest modeling level you need for it to look good
- the bulbs glass always needs a lot of refractions, I would go with 25-35 reflection/refraction trace depths to get realistic refraction.
- for each object you need to number the bulbs sequentially so you know which is bulb 1, 2, 3 and so on.
- since you are in maya you are in luck. You can link your self illuminated material of the filament on/off state to the vray light on off state.
- I would animate one bulb vray light turning on/off and copy that animation with offset to the rest of the bulb lights, you can use free script called craOffsetKeys.mel (I can send that to you if you want)
- I would render the animation in 2 layers, 1 beauty with bulb lights always off. 2 every light in the scene is off except the animation of the bulbs, then in comp add them together.

[mike_verta]

Okay this is great but a couple questions: If I use invisible spherical lights around the bulb geometries, do they interpenetrate the glass bulbs, as in surround them, or do they have to be offset? And I assume I'd be unlinking the spherical lights from lighting up the glass or filaments geometry as well.

"- since you are in maya you are in luck. You can link your self illuminated material of the filament on/off state to the vray light on off state."

This is super-intriguing. How? I usually use maps in the map slot, and those maps don't just provide black/white (on/off) states for the glow, but actually fade like incandescent bulbs do. So we're talking about maps which provide an intensity gradient for each filament. I'm wondering if there's a way to link the sampled intensity of the map (say 0-255) to the intensity of the bulb. Would probably need a multiplier there, too...

[Morbid Angel]

I would place the vray light close to the filament inside, if you want to animate the light turning off as a range, don't use maps. Just animate the float value of the light's intensity. Essentially vray light will just illuminate the scene, filament will provide detailed reflections. If you want to get granular you can use vray mesh light, so in that way you can just light with the filament, but it may be more expensive to render it.

[mike_verta]

I would place the vray light close to the filament inside, if you want to animate the light turning off as a range, don't use maps. Just animate the float value of the light's intensity. Essentially vray light will just illuminate the scene, filament will provide detailed reflections. If you want to get granular you can use vray mesh light, so in that way you can just light with the filament, but it may be more expensive to render it.

And I would assume inherently noisier?

[Morbid Angel]

yeah, but it won't be terrible.

[SonyBoy]

I'd also do some testing if you plan to animate light intensity. I have experienced this simply being ignored at render time in the past.....