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Ring and Lines
Ring and Lines
Comments: 0
Horo

29.03.2024, 07:09








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Hotel Room Scenario
Hotel Room Scenario

            

Hotel Room Scenario
Description: Another study on global illumination for enclosed indoor scenes. I had begun to use spotlights mapped along the major walls as the indirect light. It is very accurate in some ways but difficult to set-up, along with not doing well with corners. Since there are no strongly colored walls I am assuming most of the color bleed would be minimal and therfore somewhat negligible. So I borrowed from the GI tutorial. In this case I have used a random cluster of 200 lights as the ambient or indirect in the room. Naturally all materials have no ambient glow assigned within the material lab, for those who are just joining us and our discussion on realistic lighting. The textures are simple, a wallpaper I found online, a really great wood texture I created a while back, and a fabric I have developed for the curtains and bedspread and chair. Not much magic here. The beds, chair, and dresser drawers were imported. The Room itself the doors the lamps all modeled in TrueSpace. I am not much of a modeler yet but that is my next thing to tackle. Outdoors is a Dystopia block.

Light as mentioned is a cluster of 200 lights for indirect. Two visible direct lights as lamps. There is a trick to the lamps but I will discuss that at some other point. The outdoor light is a single radial as sunlight and ibl as skylight.

I really need feedback on this one. It is again minimal, not a fully stuffed turkey because my goal is the lighting study. The scene is highly enclosed, this is alot like being a nighttime scene because the sun and sky have little direct influence from this angle.

Thanks all for your time. Feedback is most appreciated.
Added by: rashadcarter1
Keywords: rashadcarter1, bryce6.1, truespace, psp7
Date: 08.19.2008 05:32
Hits: 6274
Downloads: 97
Rating: 0.00 (0 Vote(s))
File size: 718.1 KB
Previous image: Small Living Room



Author: Comment:
richter
Member

Join Date: 04.15.2004
Comments: 1092
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Ok.. I'm not sure where to begin but let's see. Textures, models and materials are not our primary topic here, but I've got to tell you that the wallpaper looks very good and so the door and the bed as modeling work!

We were talking about the strength of the shaded areas. In my render they were too deep, but that was justified to some extent by the intensity of the main light in the room. However this thing needed correction. Right here you seem to be on the opposite side - your shadows are too weak if only two direct light sources are present and not much sunlight from outside, and I'm not being picky. For an almost night type of scene the shadows on the floor in front of the door create the illusion that the floor material has some ambient added. It just pops up too much compared to the rest of the environment. The white bed under the sheet is also affected bit.

Another thing, remember the light saturation in night scenes I was talking about? You might have tinted your lights, but it is hardly visible perhaps because of the light cluster applied. The cluster washes it out from the walls and ceiling. In order to be a little more specific about the saturation I provide two photos with different light colors in scene: Photo1 and Photo2. The first one is tinted blue, the second one has more complex influence over the room because it combines its color with the other lights in scene plus the wallpaper that doesn't seem to be white at all. But you get the idea. Photo2 also shows how the light in the room affects the exposure of the camera and the overall contrast of the image. In your scene the contrast is "linked" to the shadow blackness and light intensity. I get the impression of the near light being a lot weaker compared to the far one with an almost pure burning white core (which I very much like, it is realistic effect). Maybe the low power of the near light was intended? Different bulbs in the house? That could explain it.

The "sunlight" I perceive more like a fullmoon light judging by the brightness of the lightspots on the floor. Otherwise you'll need darker window glass to motivate the low intensity of the spots.
The lamps I guess are made of two spotlights pointing to the ceiling and the floor and one radial light in the center to illuminate the inner part of the lamp and distributing more diffused/dispersed light arond the horizontal orbit. The material might be something slightly transparent, who knows. It's up to you to tell.

Overall I think with more contrast the image will get closer to reality in terms of lighting. From there the models, textures and material you will adjust as necessary. I hope I've been comprehensive enough, Rashad.
08.19.2008 11:09 Offline richter richter at cold-may.com
Render Man
Member

Join Date: 11.10.2007
Comments: 358
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I think the scene looks good but I don't have a grasp on lighting as well as Richter. What I have suggested in the past is to find a picture on the net that is similar so a person can have something to compare to.

There are so many variables with lighting and how things should look it is hard for me to really know. Even the light bulbs in the real world give out different kinds of light.I don't see any banding or shadow over lap which is sometimes caused by the flat spotlights.

Over all would have to say the same as Richter's last comments. I can see this room looking this way in the real world. I am sure it must have taken allot of time working with the lighting to get this set up.
08.19.2008 12:29 Offline Render Man alreich_4 at msn.com
rashadcarter1
Admin

Join Date: 06.04.2006
Comments: 2610
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Yes Richter, I understand what you are saying. I did play it safe with the saturation of the lights, I sensed they were not quite right and I should have considered the saturation issue more closely especially because indoor lights need that yellowness to feel legit, I know this from the Livin Large scenarios. I forgot to add that there are some radials in the bathroom area to bounce around the sunlight that enters in behind the door.
I considered tinting the cluster but I felt there were not too many strong color influences, I was not sure if I would overdo it. What I am getting from you is that I can take further risks.

Yes, the lamps are rigged the way you desribe with the up and down facing spots with the center radial, it is a time saver because I have disabled the shadow casting of the shades . So to create the impression of the shade acasting a shadow I used the up and down facing spots at double the intesity of the center radial. it shaved many hours off the render, I wish I had thought of this when I first rendered livin Large the original. You are wise and correct to note the lamp shade brightness issue. I struggled with it a bit. This I blame the cluster for as both shades are the same material and that material slightly transparent and therefore sensity to all lights used in the room. As you know I began using spotlights along the walls at first. Spots are good because they place the lights along the wall and the light leaves the wall traveling toward the center of the room dimming as it goes the way nature intended. In a spotlight mapped render the center of the room is the darkest part of the room because of the spotlight falloffs. But in the case above I did things the opposite way utilizing a random cluster of radials filling in the 3d space. This causes the center of the room to be the brightest area as the radials overlap. The lamp shade in the far corner looks brighter because all of the radials in the cluster are striking it adding to its brightness. The near shade does not show us its brighter side lit by the cluster. Truthfully the wall behind the near shade should be bouncing a strong light toward the shade and if I had aligned spots along the walls I would have easily captured the effect. I might update this one to see if I can get an effect closer to what you desribe. FYI my shadow intensity setting is 100%, full black. All surfaces are lit with lamps and the cluster along with a smidgeon of ibl light. I think the light we see entering as sunlight might actually be only skylight, the buildings are blocking the intense sunlight and since I used quality 16 for the ibl I think we are getting a skylight band and not the sunlight afterall, hence the lack of brightness. A higher IBl quality would have added many hours to the render so I avoided it.

RenderMan,
Replicas are the best training one can have. Replicas are humbling to say the least. I will observe the net to see what sorts of things I can find. Good suggestion.
08.19.2008 16:42 Offline rashadcarter1 rashadcarter1 at aol.com
connorzelinsky
Member

Join Date: 03.30.2007
Comments: 394
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I am going to write a little bit less than everyone else I think. I love it. Looks very realistic. The textures you made?/ used look perfect. The wallpaper looks especially good. I also like how you set up the room. Looks like a hotel room I would like to stay in.
08.19.2008 17:08 Offline connorzelinsky connorz16 at gmail.com
gat
Member

Join Date: 12.21.2006
Comments: 667
.

very nice lighting, and textures, once again ultra realistic
08.19.2008 17:51 Offline gat brshkv at yahoo.com
ecurbsemaj
Member

Join Date: 08.01.2008
Comments: 43
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I am no expert, my only quibbles are the shadows from the ceiling fan and the light through the windows. On the former, if you have only two lamps lighting the room, why so many shadows on the ceiling. On the latter, you have light angled in on the right side of the frames while the light on the floor angles to the left. Somewhat minor, but with the complexity of the lighting setup, that seems to have been overlooked. From an artistic standpoint, the image looks good.
08.19.2008 19:04 Offline ecurbsemaj bbeilhar at tampabay.rr.com
rashadcarter1
Admin

Join Date: 06.04.2006
Comments: 2610
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Thanks Gat and Connor. ecurbsemaj,thanks for you input also.

Ecurbsemaj,
As you know indirect light in Bryce is not easy to get right. The theory tested in this scene is of using a radom cluster of radial lights to provide ambient. In the case above 200 radsials were used and the shadows are well blended in most cses but the fan gives them away. This is one of the drawbacks of the random radial cluster. The more lights in the cluster the smoother and less noticeable those shadows would have been. Also, if I had disabled the shadow cast from the radial cluster this banding would not be an issue but then again the scene would begin to look horribly flat very similar to ambient channel glow which is far from realistic. The outdoor light as mentioned above is from the Image Based Lighting skylight. not the sun itself. I used quality 16 which means that only 8 ibl lights are above the horizon affecting the scene. What we are seeing is not the sunlight because my sunlights are always very bright, in this case it is the ibl light, as only one of the 8 lights seems to have made it around the buildings outdoors to reach the interior of the room. If I had used a higher ibl quality the spot on the floor would have been dithered with many more ibl lights from many more directions through the windows making it obvious it was indirect skylight and not direct sunlight. Also back indoor, If I had used perhaps 500 radials in the cluster of lights as ambient the banding of the fan's shadows would disappear from the many overlapping lights. So in conclusion what we are seeing are the problems that are casued by using too few lights. The more lights the better both for Image based outdoor indirect skylight and indoor indirect light.
08.19.2008 19:56 Offline rashadcarter1 rashadcarter1 at aol.com
Horo
Admin

Join Date: 05.26.2004
Comments: 4721
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First, this scene looks quite complete to me. The bedspread is excellently modelled.

To light. Now richter made a most important statement in his the Attic - Night-time when answering to your remarks. Photorealism - and that's what you're after - has a lot to do with film speed and the white balance setting. Photo 2 richter put a link to is a photo with the white balance in the camera set to daylight, hence the ugly yellow. Also, it is overexposed but photorealistic nevertheless for the simple fact that it is a photograph. The blue of Photo 1 is difficult to account for. I've seen blue when photographing in a room with bulb light and daylight seeping in through a window and having the camera white balance set to bulb.

Your hotel room was photographed with several different exposures, combined to an HDRI and tone-mapped. You will never see the bulb distinctively so near the camera and have the shadowy parts so bright on a LDRI photograph. You can't argue that the lamp shade absorbs that much light because I can see through it to its other side. The fabric is very fine and highly tranparent.

The shadows cast from the random radials is indeed a problem we have to face. We propose not to use soft shadows but then, we mix that light with the reflection map and the initial scene. Just using the radials to fake bouncing light asks for a different strategy. I don't know for sure but I think soft shadows ought to be engaged. I've also noticed that you may get away with less than 200 radials. David rendered successfully with 64 and I've used 128 in my experiments. If you can get away with half of what you've used here, this might compensate a bit for the soft shadows considering render time.

IBL - I think it may be a bit of an overkill here. If you think it is important, give it more lights. With 16 lights, the shadows get wrong. I've noticed this on all my probes I've made from outdoors recently. The sun is at 0 deg. and you expect the shadow pointing to 180 deg, but it points to 240 deg. Only if I go to 64 lights and beyond in my test setup I get the shadow at exactly 180 deg.

Photorealism has many variables: film ASA, exposure time, f-stop. We may standing in the same room and each of us takes photographs and each one gets a different one. It finally depends on what you want to say with the "photograph". My hotel has bright rooms or my hotel has cosy rooms, or my room is ideal for spending a week or two in it or it has the intimity for two persons wanting to be close. It has a lot to do with mood and a photographer attempts to get the mood his customer wants to be conveyed in the photo that will finally appear in next years catalogue.
08.20.2008 17:29 Offline Horo h.-r.h.wernli at bluewin.ch https://www.horo.ch/
rashadcarter1
Admin

Join Date: 06.04.2006
Comments: 2610
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Wise words Horo. The soft shdows idea I find daunting. This is not a failue to acknowledge the truth of the statement, just that even 64 lights with soft shadows would take weeks. I think such settings are still out of reach for me. Ideally the soft shadows would complete the indirect impression. The results would be amazing.

In the way of photorealism I am at a disadvantage becasue I do not know camera processes. A bit like learning ballet before learning hip-hop, understanding photography before learning Bryce has given you a super understanding of what is possible and why. I envy that talent. This idea of filters is essential so I will study this further, thanks.

I did not model the beds, they were downloaded from turbosquid or renderosity. Normally one would not expect to see unmade beds in a hotel room but the fabric falls so nicely that we still like it. I agree the model was very well done. It is low in polygons also.
08.21.2008 20:47 Offline rashadcarter1 rashadcarter1 at aol.com


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