> Samuel Benge wrote:
>> Tim, it's a crazy thing you tried. It did work out, though! The render
>> time
>> isn't as bad as I would expect with such high settings. The emitting
>> media is
>> meant to simulate a plasma screen, yes?
>
> LCD. One of the newfangled insanely-bright ones.
>
>> I'm not sure if you are aware of this, but there is a way to reduce
>> radiosity
>> artifacts even when you've reached your 1600 samples limit. You can do
>> this by
>> adding a tiny surface normal to your objects. I usually use
>> normal{bumps /*.25*/
>> scale .001} and antialiasing with a low threshold (+a0.01). You should
>> still
>> keep a low error_bound, but you can get away with lowering the
>> nearest_count
>> down to 1 and maybe even use a lower samples count.
>> The biggest problem is reducing the appearance of noise, but with
>> adequate AA
>> settings you can make things look pretty smooth. IMO, it's preferable
>> to the
>> standard radiosity artifacts. I think even Thomas would agree :)
>
> Huh. I should try that. Due to egging on from someone on 4chan's /3/
> board, I bit the bullet and finally downloaded the latest beta and am
> rendering a version with an image that has a better range of colours.
> Holy crap 3.7 is faster than 3.5. So much so that I decided to really
> push the settings...
>
> I dropped the brightness from 10 to 2, kept 1600 samples, dropped error
> bound to 0.01, 0.005 minimum reuse, 20 nearest count (to keep the sharp
> edge of the shadow from being all grainy), but lowered recursion limit
> to 2.
>
> I wanted to show as much of the colour-bleed effect as possible, so had
> to hunt around for a better image...I actually tried setting gray
> threshold to less than 0 (shouldn't that in theory increase saturation?
> haha) but it only allows 0--1. :(
>
> It's coming along quite nicely. The walls are a bit sluggish, but it
> flies through the media itself like it's not even there.
>
> I long for the day when I can use Moray in conjunction with this.
>
> --
> Tim Cook
> http://empyrean.freesitespace.net

Emissive media is fast to compute: no shadow tests.
Media don't receive radiosity lighting.
Your media is very bright relative to the surfaces behind it, making the 
radiosity sampling for those areas bailout immediately.
End result: your media renders very fast compared to the rest.


Alain

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