PDA

View Full Version : non-additive light?



erikals
10-06-2009, 02:52 AM
is there any way to make a non-additive light?
or maybe there is a plugin?

i'm trying to achive the effect to the right of this picture...

http://www.newtek.com/forums/attachment.php?attachmentid=78076&stc=1&d=1254819433

Lightwolf
10-06-2009, 04:43 AM
The lighting itself is computed within the shading, so you'd need a special shader as opposed to a special light.

Basically, instead of adding all lighting, only use the maximum.

Do you need it for a whole scene or just for a single surface with a specific set of lights?

Cheers,
Mike

erikals
10-06-2009, 05:41 AM
true, it more about the shading i guess, would've been nice to just add a light though.
simple...

i didn't quite understand... "Basically, instead of adding all lighting, only use the maximum."

usually for this i only need 1 surface that is affected.

i'm trying to use this for a non-GI sss trick i will post in the "Radiosity, animated" thread
http://www.newtek.com/forums/showthread.php?t=98861&page=28
getting closer, but not quite there just yet...

Lightwolf
10-06-2009, 05:48 AM
true, it more about the shading i guess, would've been nice to just add a light though.
simple...

i didn't quite understand... "Basically, instead of adding all lighting, only use the maximum."

The former is what the shaders do internally, the later is how you'd like to see them behave.


usually for this i only need 1 surface that is affected.

Using how many lights?

Cheers,
Mike

erikals
10-06-2009, 05:54 AM
...3 lights should do i think,

Lightwolf
10-06-2009, 06:20 AM
...3 lights should do i think,
In that case... use three single light illumination nodes from the db&w tools, one per light, run the results through a colour to scalar, then max them together and use the result to modify your plain surface colour.

I just checked, unfortunately there is no max node for vectors or colours :(

Cheers,
Mike

Jarno
10-06-2009, 06:43 AM
Or fake it with a single spotlight with a mask in front of it?

---JvdL---

erikals
10-06-2009, 06:57 AM
Or fake it with a single spotlight with a mask in front of it?

---JvdL---

nah, the problem is GI is too slow using SSS (unless it's Sigma2)
http://www.newtek.com/forums/attachment.php?attachmentid=78074&d=1254816678
so i simply exclude the GI from the SSS sphere...
however that creates zero light in the shadow, looking unreal

-------

so now, i add a second light, good, but it also adds light while it's in the light, making it look funny...
hm, think i have an idea, adding a 3rd light... and excluding objects...

erikals
10-10-2009, 11:38 PM
nope, can't this to work.

there might be a way using nodes, maybe Gerardo would know...
it would probably have to be some sort of buffer node... or difference node, if such exists...

hmm,...
http://www.newtek.com/forums/showthread.php?t=71751
http://imagic.ddgenvivo.tv/forums/PFconfig.png

gordonrobb
10-11-2009, 01:50 AM
Or render each seperately, then comp them in Photoshop with a layer blending type that does what you want.

erikals
10-11-2009, 04:07 AM
...yes, i kinda thought about it, but no blending type works... (tested all)

...but even if i did, it would in this case, as i'm rendering sss, make previewing the sss very tricky, going back and forth between PS - LW to see the effect.

so, a good idea, but i'm finding it tricky at the moment.

WCameron
10-11-2009, 11:04 AM
I think the old Lume somethingorother from Dynamic Realities did this sort of thing. maybe G2 can?

- Will.