Artificial lighting setup - i.e. no real direct sun light

larry_g1s · Post by **larry_g1s** » Tue Jun 24, 2008 7:12 pm

I've done a couple of scenes with Kray that I'm starting to be pleased with. And I think the new light portals are going to be fun when I eventually get to try them.

I'm looking to redo an conference scene I had before Kray. So my question is, how would one go about setting up a scene that is primarily lit using artificial lighting? Much like an office that doesn't get direct sun light. What types of lights would you use (spot, etc.), or would you still use luminous poly's? Thanks for any advice.

Pheidian · Post by **Pheidian** » Wed Jun 25, 2008 8:00 am

There are many ways, but I've used a lot of area lights in a rooms where there is not any or very little windows to get quite good results... They're easier to setup than luminous polygons and are always 100% invisible without any tweaking and tricks...

larry_g1s · Post by **larry_g1s** » Fri Jun 27, 2008 9:29 pm

What about when you're trying to portray light from an over head lamp (see example)? Would you use a spot light then, like one would usually do setting up the lighting, or is Kray different?

Janusz Biela · Post by **Janusz Biela** » Fri Jun 27, 2008 10:51 pm

Larry_g1s wrote:What about when you're trying to portray light from an over head lamp (see example)? Would you use a spot light then, like one would usually do setting up the lighting, or is Kray different?

For small lamps maybe try use spot light.
Try this scene (skyportal in window)

larry_g1s · Post by **larry_g1s** » Sat Jun 28, 2008 6:35 am

Thanks Johny, I'll try it out. The scene I'm trying to light will work in certain areas with light portals, but other areas it's too far removed from windows. I appreciate you sharing the scene.

mk · Post by mk » Sat Jul 05, 2008 11:55 pm

Oh thank you very much.
Your scene was very helpfull

I don't understand completly your setup (commands, skyportal shader,etc.. )
But my scene was very dark (small window and a large room), now my scene is very luminous.

Please more tips !!!

mk

Janusz Biela · Post by **Janusz Biela** » Sun Jul 06, 2008 1:04 pm

mk wrote:Oh thank you very much.
Your scene was very helpfull

I don't understand completly your setup (commands, skyportal shader,etc.. )
But my scene was very dark (small window and a large room), now my scene is very luminous.

Please more tips !!!

mk

What You no understand?

mk · Post by mk » Mon Jul 07, 2008 8:07 pm

After reading the Wiki, I found some answer but I still need help.

I did a copy of your "setup", the only difference is I have a gamma value of 1.
I did a skypportal

As you can see, my picture is dark - very dark.

How can I setup my scene to get a light like this picture (do I have to fake light ? )
note: when I use gamma (high value) , I loose all the diffuse.

http://www.kraytracing.com/image.php?di ... _roomB.jpg
http://www.kraytracing.com/image.php?di ... 700226.jpg

Do I have to fake the light ( not real light) ?

If you can help me.

Thank you.

my picture:

Janusz Biela · Post by **Janusz Biela** » Mon Jul 07, 2008 9:46 pm

I no see light from skyportals....
Maybe You make wrong setup (no fill light) just sun light.....
Please check skyportals in windows:
1/ All skyportals panel in hole windows must have direction for OUTSIDE room.
2/ must have : first shader kraysurface opt. invisible, second shader LIGHTPORTAL for Gi.

Maybe lumi sphere have few luminescence?

mk · Post by mk » Mon Jul 07, 2008 9:59 pm

ok I will check right now...
I will be back to you in few minutes

mk · Post by mk » Mon Jul 07, 2008 10:10 pm

Can I send you my scene to "debug" it ?
I don't see what's wrong.

I got more light , by using higher value for the sphere around my scene (selfillum from 300% to 1000%)
I got more light in the room, but I see no effect from the skyportal.

Janusz Biela · Post by **Janusz Biela** » Mon Jul 07, 2008 10:22 pm

mk wrote:Can I send you my scene to "debug" it ?
I don't see what's wrong.

I got more light , by using higher value for the sphere around my scene (selfillum from 300% to 1000%)
I got more light in the room, but I see no effect from the skyportal.

Check again this scene: http://www.kraytracing.com/forum/download.php?id=1848

what use skyportals and lumi sphere.

mk · Post by mk » Mon Jul 07, 2008 10:54 pm

I am starting to get better lightning.

I use a stronger illu for environnement sphere.

I don't use "cache irradiance" now, that give me better "pure white" surface.
I think I need to change the surface of the floor (black is not the best choise to reflect the GI inside the room.)

Cache irradiance make the render a bit "dirty" due to the blur process.

thanks for your help

Janusz Biela · Post by **Janusz Biela** » Mon Jul 07, 2008 11:13 pm

Try exponential 2.0 , 10 bounce light . When render is too dark - please add 1.5 or 2 Multiplier in Kray.
And ofcoarse sunsky turbity 6-7 on lumi sphere.

mk · Post by mk » Mon Jul 07, 2008 11:27 pm

very interesting ( Exponential 2.0 + multiplier 2.0) are very good for dark scene.
here is what I got only by changing those 2 parameters

-----------

about bounce light : are you talking about "recurse 10;" command ?

sorry, I dont understand "sunsky turbity 6-7". What do you want me to do ?
thanks again

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Artificial lighting setup - i.e. no real direct sun light

Artificial lighting setup - i.e. no real direct sun light