Chaos Corona Forum

General Category => Gallery => Work in Progress/Tests => Topic started by: tomislavn on 2014-08-18, 22:38:15

Title: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-18, 22:38:15
I am working on a restaurant visualization at the moment and I have decided to use Corona as my primary render engine. This is an early light study preview after few days of modeling the furniture and general layout.

What do you guys think about the lightning? I will be using around 40 IES lights, 12 Corona standard lights and Corona sky/sun with some portals on the front door.

I am kind of concerned about the whole look since, by the design, most of the furniture will be using a dark material. Do you think I will be able to pull it off with this setup or should I change it? I am getting pretty much the same results when I replace Corona sun/sky with HDR.

I think the main problem might be that the only light entrance is the front door - there is no windows anywhere.

I would really like to hear any kind of feedback from anyone that had similar setup/problem.
Title: Re: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-19, 12:20:00
No lightning tips for those small opening, "bigger than a kitchen/living room" scenes? :/
Title: Re: Restaurant Viz - Lightning
Post by: romullus on 2014-08-19, 12:46:53
If there's small openings and you want that ambient light would play significant role in lighting, then definitely, portals are your friends.

As for tips, it deppends on what mood you want achieve. You can turn all artificial lights on max power and get flat lighting, that shows well all geometry you put there, but are rather boring, or you can try to find fine balance between artificial and ambient light.
Title: Re: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-19, 13:05:34
If there's small openings and you want that ambient light would play significant role in lighting, then definitely, portals are your friends.

As for tips, it deppends on what mood you want achieve. You can turn all artificial lights on max power and get flat lighting, that shows well all geometry you put there, but are rather boring, or you can try to find fine balance between artificial and ambient light.

Thank you very much for your feedback Romullus, I appreciate it a lot! When you say that I should use portals - that means only on front door openings, right?
Title: Re: Restaurant Viz - Lightning
Post by: romullus on 2014-08-19, 13:15:18
If that's the only openings, then - yes :]
Title: Re: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-19, 13:16:40
If that's the only openings, then - yes :]

Hmm okay, thank you! There are 7 small planes with portal material on each door window opening already (on the sample render) so I guess that should be it then.

Need to work on the materials then check it out again :)
Title: Re: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-20, 12:02:55
Hmm, I am not quite sure how to feel about this. I have started to work A BIT on the material/lightning part and I am already starting to think that the lightning won't suffice without major tweaking.

Light setup: I have switched from corona sky/sun to HDR (PG's Clear Sky 1224) and at the moment there is around 30 lights inside of the casings that are ON. There are portals (with portal material) on the front door glass openings.

Here is a sample render (low quality, 5min quick preview with 20 passes) to get the general idea. No tweaking or post was done.

What do you guys think?

Title: Re: Restaurant Viz - Lightning
Post by: agentdark45 on 2014-08-20, 12:39:10
For interiors I tend to get them lit properly with natural daylight first. Imagine you were a photographer standing in the restaurant with all lights turned off, what would you see and would it be as dark as your render? After the render looks fairly ok, I'd then bring up the artificial lighting to a sufficient degree and drop the exposure slightly.

It seems like you need to tweak your exposure / highlight compression quite a bit judging by the test render in order to get the room lit evenly without harsh burnouts.

Another problem you might be having is that the black floor material could be too black and not bouncing enough light around the scene?
Title: Re: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-20, 13:20:14
For interiors I tend to get them lit properly with natural daylight first. Imagine you were a photographer standing in the restaurant with all lights turned off, what would you see and would it be as dark as your render? After the render looks fairly ok, I'd then bring up the artificial lighting to a sufficient degree and drop the exposure slightly.

It seems like you need to tweak your exposure / highlight compression quite a bit judging by the test render in order to get the room lit evenly without harsh burnouts.

Another problem you might be having is that the black floor material could be too black and not bouncing enough light around the scene?

Thank you very much for your feedback! Thing is, I can't really seem to light this scene good enough without using artificial lights. I have tried corona sky/sun combination, then HDR only - but each time I try to get it lit enough, I get insane burns that not even highlight compression can fix.

I guess it must be the floor material that is causing that. Without materials it comes out just fine.
Title: Re: Restaurant Viz - Lightning
Post by: CiroC on 2014-08-20, 17:30:53
Couldn't you control the highlight compression with the HDR Toning in Photoshop?
Title: Re: Restaurant Viz - Lightning
Post by: fco3d on 2014-08-20, 19:54:19
You have a lot of pendant light there, is that the architect choice? or it is your design?
If some design all those light, and you follow the intensity of those lamps you room should be lit correctly.  in real life those spaces don't look like those sine "Scandinavian" renderings that we see all around, with that dark floor, and dark furniture your scene will suck a lot of light.
First I would check the intensity of our spot lights, adjust the spread angle on them too, then check the albedo of your materials. if everything still too dark for you taste, you can always save as an EXR 32 bits and fix the image in Photoshop or sue hidden lights in your scene to compensate the low lighting.
AS mentioned before here if you are a photographer and the place does not have enough light, then you will have to use "fill lights" to compensate.

Check this images references from the internet, look how much light is coming from the lamps and how many are they using to compensate the lac of natural light.
Also you also will see the falloff of the sun light coming from small openings.

http://2.bp.blogspot.com/-5N9vz4sHg6U/UaI1tg87exI/AAAAAAAAABg/_Q9oiImHUCY/s400/Restaurant-Interior-Design-Ideas-and-Gallery.jpg

http://premierline.net/_ph/5/33746599.jpg?1404080958



edit :wrong link
Title: Re: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-20, 19:59:57
Thank you very much for your valuable feedback guys :) I will try to play a bit more with it. It was an architect who created/designed the layout. I am just doing the visualization of his project.

This is the last render - HDR only, no other lights are on atm.

Seems decent to me. I guess :/
Title: Re: Restaurant Viz - Lightning
Post by: agentdark45 on 2014-08-21, 01:33:38
What about aiming the sun into the room through the doors so that it casts over the seating? That should bring up the interior light levels without creating burnouts.
Title: Re: Restaurant Viz - Lightning
Post by: antanas on 2014-08-21, 03:25:39
 Hi, recently I worked on similarly lit project and one thing I can tell - that lighting scenario sometimes can be a real pain in you know where :) Well from my recent experience or rather my recent mistakes, you can learn this:

- 1st portals should be done similar to this
- on the outside of the window\door facing the interior plus one portal plane should cover entire opening no need to add portals for each of the window's glass parts, sorry if I'm mistaken about what you did, but you wrote "Corona standard lights and Corona sky/sun with some portals on the front door" so I made a suggestion you didn't set up those correctly and portals done that way (I mean multiple portals, especially if done on the interior side of the window) can produce some ugly-never-going-away noise or just do not speed up rendering at all - it depends on the situation

- 2nd try to make window glass one sided geometry with thin(no refraction) option ticked in its material - this is quite important, yet not just for speed or noise (well those too, but difference is not too big) but more (from my bad experience) to the power/brightness of reflections/refractions/specular coming from the hdri (probably corona sky as well but I have not tested this) and it will be quite difficult to balance lighting and reflections coming from the outside with those from the inside objects  - I don't know if that's a bug or physically correct behavior (which I highly doubt) but this happened to me so better be safe than sorry :)
 
 Hope that helps .   
Title: Re: Restaurant Viz - Lightning
Post by: snakebox on 2014-08-21, 06:19:12
Sorry to jump on this thread, but quick question to those who know... when you create a plane and add the portal material to it... does it matter which way the plane is facing? like is there an in and out? or does it boost environment to both sides? 

Also seems like intersecting geometry isn't a problem? or do people put them just outside/inside say of windows?
Title: Re: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-21, 08:03:01
@agentdark45 - Sun in HDR is already aimed through the main doors, just not straight in the middle, it has around 30 degrees offset - you can see it on the soda machine shadow. But I will try that version today :)

@snakebox - I am pretty sure that the plane (portal material) works both ways, no matter of the facing.

@antanas - First of all, thank you very much for you suggestions. Yeah I have a separate portal plane for each window (7 in total on the front doors, but they do not overlap) - it might be wrong :/ so I will try to cover whole doors with one big portal. I am creating portals from the inside maybe a few inches apart from the actual window, so that might be the problem as well. All my glass materials in this scene are already having the "thin" option ticked.

I am open to more suggestions :) it helps a lot! Now back to experimenting!
Title: Re: Restaurant Viz - Lightning
Post by: romullus on 2014-08-21, 10:20:51
I do agree about portals, but not necessary so about windows glass. With Corona, i almost never use "thin" glass hack, because i find it unnecessary. Glass with real refraction works very well in most scenarios and look real.
Here, in this image (https://forum.corona-renderer.com/index.php/topic,2466.msg32000.html#msg32000)  i used two boxes (4 surfaces total) for window glasses with physical glass material and it doesn't has any negative impact on render speed.
Title: Re: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-21, 10:28:51
I do agree about portals, but not necessary so about windows glass. With Corona, i almost never use "thin" glass hack, because i find it unnecessary. Glass with real refraction works very well in most scenarios and look real.
Here, in this image (https://forum.corona-renderer.com/index.php/topic,2466.msg32000.html#msg32000)  i used two boxes (4 surfaces total) for window glasses with physical glass material and it doesn't has any negative impact on render speed.

Yeah I agree on the glass material, I have tried it now without Thin option and it renders the same speed and it kinda looks the same also - but that's because I am using a simple plane for glass not the box like in real-life example I guess. Tnx :)
Title: Re: Restaurant Viz - Lightning
Post by: antanas on 2014-08-21, 12:25:48
Sorry to jump on this thread, but quick question to those who know... when you create a plane and add the portal material to it... does it matter which way the plane is facing? like is there an in and out? or does it boost environment to both sides? 

Also seems like intersecting geometry isn't a problem? or do people put them just outside/inside say of windows?

Well from my tests when portals are made outside the window noise goes away faster, about the direction, well here I'm not sure cause every time I did portals I did them with normals facing toward interior cause that just seems logical to an ex v-ray user and more important what would be the point for portals to work for both sides (if I'm wrong, someone please correct me), about portals intersecting geometry - I had read somewhere on the forum what it does not really matter but nevertheless I try to avoid that just in case. Still I'm surely not the most knowledgeable corona user in the world so better to wait till someone preferably Keymaster or Rewalanche decides to elaborate us on that matter further, of course if there is further to it :) 
Title: Re: Restaurant Viz - Lightning
Post by: antanas on 2014-08-21, 19:49:19
Well maybe I've done something wrong or that was some specific build bug at the time which was corrected later, but there are the differences which I mentioned :
Title: Re: Restaurant Viz - Lightning
Post by: antanas on 2014-08-21, 19:59:45
There is quite considerable difference in sample count + in the one with thin glass I had to lower that same hdri's intensity to match lighting with that one with the solid glass, cause one thing I forgot to mention before is lighting quantity difference coming from windows if those are done this or the other way, but otherwise all is the same - materials, render settings etc. Just don't freak out by those images that interior was heavily wip at that moment (strange I even bothered to save those) so it is quite unfinished/unpolished and no post at all. Nevertheless notice difference in reflections, refractions and the lighting itself and judging from Rewalance's post in this thread https://forum.corona-renderer.com/index.php/topic,135.msg14557.html#msg14557 more specifically this line "If you use regular thick glass with refraction in windows, any ray that passes through it is considered a caustics and your scene will take extremely long time to render..." that behavior is quite explainable though I didn't notice any considerable speed improvements when using thin glass, well maybe some but surely not extreme :) 
Title: Re: Restaurant Viz - Lightning
Post by: snakebox on 2014-08-22, 03:36:08
Well maybe I've done something wrong or that was some specific build bug at the time which was corrected later, but there are the differences which I mentioned :

This seems like a pointless comparison, no data on passes, light is clearly different. 

Interesting topic though, personally I have always used the box method until recently after reading around, now trying the single face plane with (Thin) but I don't notice any real difference in rendering, so I guess ill have to setup a side by side test too as it would be really good to know what is happening.
Title: Re: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-23, 18:36:14
A little update.. raw render while working on the materials, kitchen counter side, 88 passes only :) - looking pretty good!

Title: Re: Restaurant Viz - Lightning
Post by: antanas on 2014-08-24, 14:19:59
 Hi I think a texture of the wood\wood-looking tile material on the floor is a little bit too small for that purpose and I think tiling could be a little more dense plus it surely needs some randomization, those tiles look like they've been made using floor generator and if so you could easily randomly shift uvs on those using for example this http://www.scriptspot.com/3ds-max/scripts/mass-randomizer nice script. Anything other than that - hmm, its a bit too early stage of the making to advice something :).
 About that which I wrote earlier (reflection dimming with solid geometry glass) - I've done some more tests, more accurate this time and put results in my own thread https://forum.corona-renderer.com/index.php/topic,2361.0.html , well reflection dimming is still there, yet I'm sorry, I was wrong about lighting differences - it really was my mistake.
Title: Re: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-25, 10:36:34
Hi I think a texture of the wood\wood-looking tile material on the floor is a little bit too small for that purpose and I think tiling could be a little more dense plus it surely needs some randomization, those tiles look like they've been made using floor generator and if so you could easily randomly shift uvs on those using for example this http://www.scriptspot.com/3ds-max/scripts/mass-randomizer nice script. Anything other than that - hmm, its a bit too early stage of the making to advice something :).

Hey Antanas, thank you for your comments :) - I am aware of it and as much as I would love to do that, I am running out of time and since this should've been some quick/rough viz of the place with some simple textures, which in the end got switched to a some kind of a semi/photorealistic project - I can't really afford to work more on it. I am rendering the final pictures now and it should be ready for tonight (deadline).

I will definitely try to do some more work on it in my spare time (which I kinda lack though) so I can have this shine in my portfolio though :)

Here is a raw render of the first view - 230 passes, took 2h45min on my i7 4770k machine. Kinda not sure what to do to make this noise go away completely in the ceiling and above the counter (apart from leaving it cook for like 4-5 more hours which I cannot do at this point).

Title: Re: Restaurant Viz - Lightning
Post by: romullus on 2014-08-25, 11:24:21
I think, there's something wrong with some materials in your scene. There's too much noise left on walls for 200+ passes.
Title: Re: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-25, 11:29:12
I think, there's something wrong with some materials in your scene. There's too much noise left on walls for 200+ passes.

What could it be? There is some small bump and reflection bitmap (0.04 value though) in the wall material, other then that is pretty much standard corona material with a little bit darker white (grey) color just not to make it clear white. Did I do it wrong?

EDIT: Added 2nd view, notice the noise left on counter glass (thin, simple glass material pure black diffuse, 1.0 reflection white, 1.0 reflection glossiness, 1.0 refraction, 1.0 refraction glossiness) and again the darker wall areas (in shadow mostly)

220 passes, default settings
Title: Re: Restaurant Viz - Lightning
Post by: antanas on 2014-08-25, 18:38:03
Oh I know your pain - deadlines+perfectionism+some amount of laziness or distractions suck badly :(
 On the subject - I would suggest this noise is coming from caustics produced by metal surfaces almost directly lit by those lamps check your metal's diffuse colour to be completely black check it's reflection ior to not exeed 20 (or even 10 in some cases) and if this does not help the noise situation then only longer rendertimes will or matid/wirecolor masks plus photoshop plus neatimage or dfine (noise reduction plugins) are your friends to quickly get rid of that noise without rerendering - at least those help me everytime I'm in such situations which are too frequent for my liking but still are almost inevitable :)
Title: Re: Restaurant Viz - Lightning
Post by: fco3d on 2014-08-27, 19:52:42
This is looking a lot better, You should try to put some articulation in your stainless Steel counter, and maybe play with some coated metal instead, because now it look very grainy and I don't think more cooking time will make it look better.
Also what value are you using for your black now they look very dead black.
Title: Re: Restaurant Viz - Lightning
Post by: tomislavn on 2014-08-28, 08:24:17
This is looking a lot better, You should try to put some articulation in your stainless Steel counter, and maybe play with some coated metal instead, because now it look very grainy and I don't think more cooking time will make it look better.
Also what value are you using for your black now they look very dead black.

Hey fco3d, thank you for your comments. You are right, more cooking didn't help, which I did was I reduced the IOR of the metal surface to 19.50 instead of 25 that it had before, also the reflection glossiness a bit - it kinda helped with the noise. Black is 3,3,3 if I remember correctly but I have used contrast value of 4 in Corona render options so it did make it tad too black.

@antanas - Thank you for the IOR tip :) it helped!

Anyway, this project is finished - I should post new renders in the gallery :)