Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: aaouviz on 2018-11-28, 09:01:08

Title: Simple interior lighting
Post by: aaouviz on 2018-11-28, 09:01:08
Hi All,

I'm currently working on a set of bathrooms which the client wants rendered at 7k. I've never done 7k before, so I'm trying now in my early development to optimise the scene as much as possible.

I'm wondering, if I replace the door (behind the camera, only seen in detailed reflections) with a corona rectangle light as the main source of lighting, is this workflow 'acceptable'?

Attached are two quick tests. The quicker one is with the rectangle corona light (set at intensity of 1), the longer one is with basic white Corona environment. Both of these are the only source of light in the scene. (53 seconds vs 2m)

Although the rectangle light was a lot quicker (and supposedly has lower noise), there is a lot of visible noise in the reflections - most noticeably the shower faucet. Obviously, I'll be adding more lights (probably only mostly strip and ceiling lights - corona lights, hopefully no emissive materials). The noise does seem to disappear when I do zoom renders.

Any feedback appreciated. Should I, for some reason I'm unaware of, not use the rectangle light workflow? Thanks!
Title: Re: Simple interior lighting
Post by: Kalopsia on 2018-11-28, 09:48:19
With Coronalight there is no problem at all.
If you use Environment make sure to put a Portal inside the door.
As for selfiluminationg materials, they can be used without to much trouble when you have to creat a visible light. Like a Lightboulbe. Then you creat a coronalight to light the scene and use your selfilumination only as visible light. In other words, use a CoronaSwitch material with a GI material that has no selfilumination. This prevents calulating the lighting form that material but it still shows up as a lightbulb
Title: Re: Simple interior lighting
Post by: aaouviz on 2018-11-28, 10:03:56
Thanks mate. Appreciate the reply.

Am I right in understanding that the Portal won't illuminate the scene more, but will improve the calculations (speed up the rendering/less noise?).

Generally, should portals be used in all cases where exterior environment illuminates interior scenes? Ie; with HDRI, Corona Sky, etc?
Title: Re: Simple interior lighting
Post by: Kalopsia on 2018-11-28, 10:37:23
Yes, portals speed up calculation. In fact, in Coron it is not like in Vray, you won't find the portal inside the lighting section but as a material, because it does not add light into the scene.
Although I think it is still true that the portal will help the light to get inside the room and thereby add light (this was true 10 years back XD) but not lighting the scene itself. So only using a Portal won't do anything.
You can even use it as a submaterial, this is great when using a box as room and using MaterialID to add different materials and a lightportal. So you can change your geometry in one Editpoly and the lightportal will fit perfectly.

And YES you should always use lightportals, although in the helpdesk they tell you that there are circumstances you don't need them. Many artists have done tests to establish that you always need a Portal.
Unless you use Vray Next with an adaptive dome XD