www.kraytracing.com

Hey all mighty Kray'ers! Btw, how about doing Kray t-shirts with that neat logo (silver print would be nice)

Anyway, here's a little commercial project I'm working on at the moment, rendered naturally in Kray, render time for this image was around 20 minutes (it's still for preview purposes, gonna render print version for the final)

This is my first commercial project with Kray now, and I'm pretty satisfied with the ease of it in archviz for my clients needs...

C&C welcome!

Killer Pheidian. Man...seems like you're getting Kray down pretty well. Very clean, particularly for a preview. You'll have to share some of your knowledge/settings with us if you don't mind.

Well thank you!

Basic stuff where you start tweaking is using luminous dome around the model to make the base light for the room (actually that's only light here besides the sun, coz so many windows)

adding that luminous ball a surface of luminosity around 400%, with Kray Indirect shader multiply 2 or so... which ever fits fine.

Then photons are pretty medium stuff except there also multiply to 2 or so. FG is min 800 max 1500 or so (depending how dark the room is -> splotches)

Then you can add from the list in tailer command the prerender command, that pre-renders the GI multiple times, adding more rays there where needed (sort of multipassing). This causes better contact shadows etc...

Just do some preview renders with smaller resolution to see what lightning looks good in your scene, but definitely use the luminous "sky dome", around 100m in diameter...

I'll guess this'll get you started... Just TRUST the Kray's power to light up the scene with luminous polygons!

I've learned very much from Johny about the Kray, who is actually a veteran of the software already... So big thanks to Johny!

Here's another preview of the project...

Killer indeed! Very clean

About using a dome. Remember some time ago using MR, I was told it's faster to go with backdrop instead of using a dome since the GI scene will be much larger = longer render times. True with kray?

Thanks again mate, Kray really rocks... G. you should make a T-shirts available with some neat slogan for Kray logo... Or just black t-shirt with white Kray symbol in back or front... It's nice design (who designed it btw?)

Dunno if it's faster or not, but definitely light is more accurate when using only luminous polygons...

What I've heard from lot of people, luminous polygons are even better every way than good old area lights... And what I've used them my self (other than skydome) it is true... Of course for some special lights simulations the luminous polygons just wont do...

Oh and I'm no pro of this stuff, I think Silverlw knows more of what is going on in Kray and stuff... I'm just a humble user learning from others...

I have wondered about use of skydomes in Kray for a while, and this is the ideal opportunity to ask I guess.

What is the benefit of using a skydome? Isn't the point of GI that you don't need to use one? Certainly when I have used them, there doesn't seem to be much difference,
but maybe that's because I am very inexperienced with Kray.

Some time ago with V1.4, Grzegorz recommended that I use one, but between v1.5 and v1.6 I stopped because it seemed to increase render time and have little benefit.

I would be really interested to hear everyone's views.

great looking renders ! congrats.

about skydomes.. is there any advantage versus using the skylight plugin? which gives a "dome like" illumination if I am correct?

which one is better?

When I have time, I intend to create a "skyportal" shader, so to speak, for luminous polygons. Basically, the shader would check the backdrop's color based on the incoming angle. I don't know if it would work with Kray's lumilights, but it's worth a go.

Pheidian wrote:Well thank you!

Basic stuff where you start tweaking is using luminous dome around the model to make the base light for the room (actually that's only light here besides the sun, coz so many windows)

adding that luminous ball a surface of luminosity around 400%, with Kray Indirect shader multiply 2 or so... which ever fits fine.

Then photons are pretty medium stuff except there also multiply to 2 or so. FG is min 800 max 1500 or so (depending how dark the room is -> splotches)

Then you can add from the list in tailer command the prerender command, that pre-renders the GI multiple times, adding more rays there where needed (sort of multipassing). This causes better contact shadows etc...

Just do some preview renders with smaller resolution to see what lightning looks good in your scene, but definitely use the luminous "sky dome", around 100m in diameter...

I'll guess this'll get you started... Just TRUST the Kray's power to light up the scene with luminous polygons!

I've learned very much from Johny about the Kray, who is actually a veteran of the software already... So big thanks to Johny!

Here's another preview of the project...

Second image is very nice as well. I'm sorry if this sound like a dumb question, but how are luminous polygons different then a sky dome?

... I'm just a humble user learning from others... Smile

I like your attitude. Humility is rare these days.

Captain Obvious wrote:Basically, the shader would check the backdrop's color based on the incoming angle.

brilliant trick, that is the thing I miss in all those pictures where people put a white arealight or lumilight in the windows. That looks exact like somebody puts a large light in a window! The ceiling is then too light because in reality there would not come white light from the ground (except only if there is snow on a bright day ofcourse)
So for me a backdrop gradient (or sunsky plugin) gives the best look. (for lightmap mode) Backdrop does not work in photonmap mode, so there you need a spheredome. But in photonmap the dome emits and wastes an awful amount of photons because those do not reach the window and inside of room. So to tackle this problem you need the upcoming Skyportals to guide all those photons only to windows (or some to the visible outside)
In lightmap mode you don't have this problem because in that mode all photons are sent from camera viewpoint instead of lights as in photonmap mode.
Hope it is all clear to everybody now, if not, please ask me to explain it better.

Captain Obvious wrote: Basically, the shader would check the backdrop's color based on the incoming angle. I don't know if it would work with Kray's lumilights, but it's worth a go.

Skyportals will work like that but no photons will be wasted as Ervin explained.

Erwin Zwart wrote:......., that is the thing I miss in all those pictures where people put a white arealight or lumilight in the windows. That looks exact like somebody puts a large light in a window! The ceiling is then too light because in reality there would not come white light from the ground (except only if there is snow on a bright day ofcourse)......

The light gets onto the ceiling also from a balkony or a terrasse in front of the window, or from the window-sill. And not to forget from the buildings next to it. But usually a skydome gives a much better result, arealights in windows are only useful for deep rooms without enough windows.

Btw nice renderings

Silverlw wrote:

Captain Obvious wrote: Basically, the shader would check the backdrop's color based on the incoming angle. I don't know if it would work with Kray's lumilights, but it's worth a go.

Skyportals will work like that but no photons will be wasted as Ervin explained.

As far as I can figure, sky portals work by guiding photons. My trick would work by having a light that changes color and intensity based on the emission angle, which is not quite the same thing.