davidstvz

Let's Trade Physically Based Rendering (PBR) Settings

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I'm wondering what settings and tricks others are using to get good PBR shots.  I've found the default settings for physically based rendering (exposure 0.2 and HSB all 0.0) don't look very good in most settings.  I've gotten some good looking shots, but using very unintuitive values for the settings. It seems the only settings we have to work with are found in "3D -> Rendering Techniques -> Technique Options" on the "Physically based" tab, and of course the lights themselves and material properties. We can change camera exposure, and HSB (hue, saturation and brightness). In the camera settings, I have all shadows, reflections, bloom and edge smoothing active (and in edit->preferences->render I have edge smoothing on high).

 

For well-lit shots (indoors and out), I've found I can usually correct the contrast by cranking the brightness up to about 80.0 and adding just a little saturation (about 5.0). From there, I set the exposure to vastly different numbers to get the shot looking right.

 

Outdoor day shots work well with exposure near default of 0.18; I use 0.20.  In fact, this looks almost identical to using default settings and then running Photoshop's automatic contrast correction on it.  Strangely, I've found that decreasing the sun's lux value from 100,000 all the way down to 10 only has the effect of reducing a little bit of bloom in the scene. You probably can't even see the difference unless you switch back and forth using a photo viewing app. Going below 10 makes the scene progressively darker, but not as if night were coming on, it's just as if the exposure needs to be different.  I might be able to get better contrast using this effect, but haven't sorted that out yet.

 

000010lumen.thumb.jpg.72adaab9cd41ed43613ca12c784ef67b.jpg100000lumen.thumb.jpg.f0f53572a04f9a1539093fb3ba7bf4a6.jpg

 

 

 

 

Outdoor night shots with many lights look good with very low exposure of around 0.005.  I added an invisible lamp to the shot below with a low brightness of 500 lumens and placed it about 30' above the camera (point mode; shadows disabled).  This added some gentle ambient lighting, otherwise the roof would have been pitch black.I could probably tweak this shot a bit.

 

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Indoor shots need something in between depending on how many lights are involved and how bright they are. For example, my fully lit kitchen shot has exposure at 0.10 (brightness still 80.0). I had to set the undercab light lumens very low (100 instead of 1200) to keep them from washing out everything.

 

kitchen-nighttime.thumb.jpg.01c91c490a97b129471393f444497cc8.jpg

 

 

 

For the cabinet-lights-only shot, I reduced the lights further to only 25 lumens, reduced exposure to 0.05 and brightness down to 0.0. I also turned on the living room can lights and made them very dim to add a little extra ambient light. I probably could have done a better job of that by putting an invisible light above the island.

 

kitchen-undercab-only.thumb.jpg.2512ce8750480a6462d0166990f4bcd2.jpg

 

 

One problem I have not solved yet is that indoor shots with the sunlight coming through windows tend to look a little too washed out.  I can't seem to find settings I like for this scenario.  First the kitchen in the morning with no lights on, and then in the afternoon with all kitchen and living room lights on.

 

kitchen-morning.thumb.jpg.48dc19d85ca5e3f9eada4b934feb2a34.jpgkitchen-afternoon.thumb.jpg.ad087fc6858323efbf68c02ffb117ca0.jpg

 

 

 

If anyone has any suggestions, I'm all ears.  There aren't a lot of settings to play with, but there are definitely some hacks to make the output look better.  Photoshop can be involved if necessary, though it would be great if HD Pro can output good images directly.

 

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With PBR there are NO specific settings that "fit all occasions", period. Each scene may or may not have a backdrop that effects lighting effects in the scene. Certain material combinations can affect how reflected light appears on other objects. The first thing I usually adjust is the lighting intensity and adjust sunlight direction and intensity until I get just the look I intend. As I said, certain colors in backdrops and room materials can adversely affect outcomes. You just have to confront what you are looking at and then make adjustments until you obtain the outcome you desire, it is an Art and NOT a Science.

 

DJP

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I agree in general as you can tell by the widely different settings I used to get the shots above.

 

I was just looking for tips and tricks I hadn’t discovered yet if anyone has them.

 

One thing I’d like to do is make darker sun shadows or figure out a way to adjust them in any case. That might be best done after the fact with a photo editor.

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A lot of people who do a lot of renders also use Photoshop or the like to adjust their images, such fine adjustments are easier to make in such applications.

 

DJP

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