Portals with interiors

[Stugys]

Hello, my question is do i need portals for better interior lighting, and do they help reduce render time, how proper way to set up it, i was googling about it, and found various answers, they are dont needed or they are for better quality, so what is the truth, or it dipends on interior situation?

[vlado]

I've been doing some experiments with recent versions of V-Ray and portals didn't really seem to help that much anymore. I would generally stay clear of them. We will also work to improve V-Ray's sampling so that there is even less need for portals in the future.

Best regards,
Vlado

[andybot_cg]

vlado When do you think the improvements in the sampling will be at the point where the portals are not needed? The most recent tests I did (maybe about a month ago now, using Vray 3.5) still shows that for a room with a small proportion of daylight openings, using portals still gives a big advantage (almost 2x faster at the same noise threshold.)

[vlado]

I have no idea yet, it's still research, but it would be clearer in a month or so.

Best regards,
Vlado

[glorybound]

I stopped using them the first time Vlado mentioned that they were no longer needed, which had to me 6+ months ago, and I don't miss them.

[andybot_cg]

I just ran a comparison of my testing model that I last rendered in May. I'm using a month-old Vray 3.5 build. The only difference between the renders is that I turned off the portal lights in the windows. I can test with the latest Vray, but it sounds like there hasn't been that much of a change in the engine since a month ago.

[Stugys]

andybot did you use simple portals, or portals, and where you placed it inside toom or outside room if i can ask?

[andybot_cg]

Simple portals with sky environment. I'll do a test with hemi light as well.

[glorybound]

Any render time hits? Is it worth the effort to add the lights if you can brighten things up in post production? Side by side you can see the difference, but it's hard to say which one is 'correct'.

[andybot_cg]

Yes, almost double time difference (the render times are in the stamp at the bottom). Seems it's only the case for env. lighting. With a dome light it's about equal with or without portals. Yes, the lighting is not identical, seems that could be adjusted by tweaking the exposure.

[zjyh2008]

emmmm，emmmm，emmmm，

[jazzmanny]

Hi! I am needing some advice i am trying to do a interior scene and i can't figure out how to light it like in the reference image here is what i have so far.

[Stugys]

Jazzmanny first of all i noticed that your top (ceyling lights) too strong, now all bright parts of image are burned out, brown furniture glossines value are too high if you trying to get really close image result like in reference, try to lower i guess below0.85, dont know. your broun furniture hight is too high, in this case you loose shadows in that gap, can you show your light setup in the scene, becaus it looks not identical for reference, I is obvious when you look in the shadows directions and spreading area on the floor

[jazzmanny]

Yeah, the issue is if i try to use like say in the reference image i see they have lights in the mirrors that has a issue when i try to put lights there and crank the light intensity so high it starts to add a ton of noise in it. So i was trying to cheat to add light in there. The hardest issue is that the light is interior and i can't add a window in there since in this reference the shadows would be messed up if i did even more so. So i am just trying to get some advice on how to LIGHT this scene because i am brand new to using vray.

[glorybound]

I would assume a lot of architectural photography gets some post production, so you might be able to go the extra mile in PS. I always run PS's Camera Raw, which balances a lot of things out. Here is your image with Camera Raw's default.