Light "Balance" Issue

[ivanjay]

Hi all,

 

I am having trouble with this model which has a daylight system coming from the outside (the wall with the sun outside is just a glass material since it is curtain wall and pretty much solid sun anyway).

 

The sunlight is creating a washed out appearance so I am turning my brightness way down. Now the sunlight looks great, but the areas not receiving the sunlight are dark as can be.

 

I cant seem to get the right balance.

 

I am using logarithmic exposure control and rendering with mental ray. My exposure control settings right now are:

 

Brightness: 25

Contrast: 60

Mid Tones: 3.0

Physical Scale: 1500.0

 

Color correction, desaturate low levels, affect indirect only, and exterior daylight are all unchecked.

 

Sun multiplier is 0.4

 

I am also not seeing the lighting effects I would expect on the walls, these are erco lights inserted into the model.

 

Thanks!

[erickdt]

What gamma settings are you using?

[ivanjay]

What gamma settings are you using?

 

Enable Gamma Checked

Gamma: 2.2

 

Bitmap Files:

Input: 2.2

Output: 1.0

 

I never know what to put in bitmap files section so hopefully that is right

 

Affect color selectors and material editor is checked.

[aaronrumple]

Use linear and expose for a nice midtone with a little burn. Export as *.exr and then tone map in Picturenaut.

[Justin Hunt]

what version of Max are you using?

[ivanjay]

what version of Max are you using?

 

Max Design 2010

 

I thought linear exposure is not compatible with mental ray? That is what the help file says.

[Lutz1973]

Hello everyone! My first post...

 

About Gamma:

Search for "Gamma pipeline" in the Max2010Design help, here's a nice diagram explainig all settings.

In short: All to 2.2

Exeptions:

Import of greyscale images like Bumps: 1.0

Import of HDR's : 1.0

Export of renderings as HDR's: 1.0

 

MR supports log and MR Photographic Exposure controls.

Linear is not supported by MR.

 

Beyond that you should leave the Sun Multiplier at 1.0 as this is photometric correct.

 

- Search for the mrSunPhotons menu (Daylight System Settings) and set a radius that covers your window opening. As your doing an indoor scene with exterior daylight you need your photons indoor.

- Use a sky portal to get some skylight indoors.

- Crank "Final Gather Bounces" in the bottom panel of the rendered frame window up. You schould not go higher than 6 bounces as your rendertimes will increase.

- Are you using GI with FG?

If nothing works you might concider setting decay (render settings, GI panel) to a lower value but be aware that this is not photometric correct.

-Play around with the position of the sun.

 

Play around with these settings to brighten up areas that are affected by indirect sunlight.

 

Keep in mind that sunlight comes in with an intensity of 100.000lx on a clear sunny day, a 60Watt bulb results in 720lx at a distance of 1 meter.

Maybe you should switch off the sunlight and light the scene with some nice IES-Files? I guess the counters are more important than the floor in the foreground.

 

Btw: The counters in the foreground need more segments and the gaps on the floor are too broad. Reduce the bump on the ceiling.

 

Please correct me if I wrote something wrong and please excuse my bad english...

 

Regards, Lutz

[ivanjay]

Hello everyone! My first post...

 

About Gamma:

Search for "Gamma pipeline" in the Max2010Design help, here's a nice diagram explainig all settings.

In short: All to 2.2

Exeptions:

Import of greyscale images like Bumps: 1.0

Import of HDR's : 1.0

Export of renderings as HDR's: 1.0

 

MR supports log and MR Photographic Exposure controls.

Linear is not supported by MR.

 

Beyond that you should leave the Sun Multiplier at 1.0 as this is photometric correct.

 

- Search for the mrSunPhotons menu (Daylight System Settings) and set a radius that covers your window opening. As your doing an indoor scene with exterior daylight you need your photons indoor.

- Use a sky portal to get some skylight indoors.

- Crank "Final Gather Bounces" in the bottom panel of the rendered frame window up. You schould not go higher than 6 bounces as your rendertimes will increase.

- Are you using GI with FG?

If nothing works you might concider setting decay (render settings, GI panel) to a lower value but be aware that this is not photometric correct.

-Play around with the position of the sun.

 

Play around with these settings to brighten up areas that are affected by indirect sunlight.

 

Keep in mind that sunlight comes in with an intensity of 100.000lx on a clear sunny day, a 60Watt bulb results in 720lx at a distance of 1 meter.

Maybe you should switch off the sunlight and light the scene with some nice IES-Files? I guess the counters are more important than the floor in the foreground.

 

Btw: The counters in the foreground need more segments and the gaps on the floor are too broad. Reduce the bump on the ceiling.

 

Please correct me if I wrote something wrong and please excuse my bad english...

 

Regards, Lutz

 

-I set all Gamma's to 2.2

-I set a radius to the sun photons (I am assuming this will not affect the rendering but improve rendering time as we are limiting where the sun shoots photons)

-Final Gather Bounces was already on 7, should I go higher?

-I already had a sky portal

-I do have GI enabled (not caustics)

-I am leaving the sun multiplier to 0.5. I set brightness in my exposure control to 35. I know you are saying this is physically incorrect but the sunlight is very much over-exposed when I do not change this.

-I lowered the bump on the ceiling and reduced the gaps on the floor, thanks for noticing that. I have been so focused on the lighting I have not looked at anything else...

-I changed the sun direction to have it "aiming" more towards the back of the space hoping to get more light there

 

I am stuck on the segments on the counter. This geometry all came in from CAD and I cannot seem to figure out how to improve the curvature of these counters... Any ideas?

[erickdt]

"I am stuck on the segments on the counter. This geometry all came in from CAD and I cannot seem to figure out how to improve the curvature of these counters... Any ideas?"

 

You need to adjust your "maximum deviation for 3D solids" downwards in the AutoCAD import dialogue. The smaller that number is the smoother your imported curves will be. I typically have this set at .001-.005

 

E

[ivanjay]

"I am stuck on the segments on the counter. This geometry all came in from CAD and I cannot seem to figure out how to improve the curvature of these counters... Any ideas?"

 

You need to adjust your "maximum deviation for 3D solids" downwards in the AutoCAD import dialogue. The smaller that number is the smoother your imported curves will be. I typically have this set at .001-.005

 

E

 

Ahhhh I always thought it was curve steps. I bumped them up to 100 I guess for no reason. What do curve steps do? The help file is confusing on this...

[erickdt]

I'm not quite sure what curve steps does either. I have mine set at 100 as well. I find that these settings (attached) work best for importing AutoCAD...

 

E

[ivanjay]

Oh well, mystery setting.

 

Now back to the big question at hand. Anyone have any idea on how to fix this lighting issue? I am getting close to out of time and having to shoot it as is a high res which I would hate to do before I solve the problem. It is due tomorrow and I need to calculate final gather map on my end before sending to my outsource farm.

[ivanjay]

Hi Ivan,

 

With your current set up, you need to focus on your GI solution

as this is providing your bounced light. With GI enabled (photons)

your FG bounces are doing nothing. Turn FG off and focus on getting

your photon solution done, then using FG to smooth it all out.

 

OR turn of GI and put your focus into using FG bounces to move

light into your interior. Be aware though that at 4 or higher, FG

bounces become far more expensive in terms of render time than

photon bounces!!

 

regards

Bri

 

Thanks Brian. The point I must be missing is how do I get the light to bounce / distribute further into the space? I shut off final gather and am rendering just to see what GI only yields.... Is it just a matter of adding more photons or....?

[Lutz1973]

The last image you posted seems bright enough for me - the floor is even a bit overbright.

The whole image lacks a bit in contrast.

Remember that you need some dark areas in your image, otherwise it will look flat.

 

The problem maybe that the centre of your picture is the darkest area.

The most important part of your scene (the counter) is dark.

 

I know time is short for you, however:

Have you tried to switch the sunlight off and highlight the counters (the most important elements in your scene) with some IES-Lights? Maybe your scene will look more vivid with artificial lights...

 

The opening seems to be quite small anyway...

 

This shouldn't take longer than half an hour to set up but could change the overal look of your image damatically.

 

You should render an ambient occlusion pass btw.

 

Good luck!

[ivanjay]

You mentioned you thought it lacks contrast... Are you thinking in terms of a setting or in total with the colors etc...

 

Your post gave me a thought.... Maybe this is not a sunlight issue but a skylight issue. Maybe the front of my model is looking too washed out and the back too dark because the entire left side of the room is curtain wall with tons of light...

 

I am going to try shutting of the skylight and leaving on the sun to see what I get.

 

How do I render an ambient occlusion pass? I have read about that before but do not really know about it. I normally just check on ambient occlusion on certain materials (walls for example) when my rendering is near done.

[Lutz1973]

"Maybe the front of my model is looking too washed out and the back too dark because the entire left side of the room is curtain wall with tons of light..."

 

That's what I meant!

A bit more color won't be bad but the main problem is:

The more you try to get sunlight into the last corner of your room, the more contrast you lose and your image becomes more and more flat.

A nice image always needs some contast.

To my personal opinion all counters and the grey wall behind the main counter should be well-lit so that the center of your image and the important elements in your scene are bright. The rest may stay low-lit.

The easiest way would be to use artificial lightning.

 

However:

Ambient Occlusion pass:

 

Assuming that you used A&D-Materials:

Render elements tab -> add -> mr a&d raw: Ambient Occlusion

Check that "enable filtering" is switched on and define an output path.

Import in PS on a seperate layer above your rendering and set the layer to "multiply".

Change the transparency of the AO layer to adjust the strenght of the effect.

 

Regards, Lutz

[ivanjay]

Appreciate all of the help all, it does sound like some artificial lighting might help here. I just have an issue doing that because it isn't "real" but the look is what is important.

 

Attached is a progress with the "skylight" off and sun on. I brought up the brightness a tad as well.

 

I think this is starting to look a lot better, your thoughts?

 

I SINCERELY appreciate all of this help, fun deadlines!

[ivanjay]

What does everyone think of this one? I think this might work well enough for the final shot.

[ivanjay]

Hey Ivan,

 

My only other thought would be to lose the 'Log' exposure

and render with the MR photographic. The whole system

just gives better results (IMHO) than using the Log Exp when

rendering with MR!

 

Looking improved though!

 

Regards

Bri

 

Now, you lost me! I just wish I could get mr exposure to work instead of logarithmic, the control is much better.. Stuff turns black on me though, I don't know why.

[Lutz1973]

The last image you posted looks much better.

If you got some time left, you could try tuning some of the colors - to my opinion there's a bit too much beige in your picture.

The counters in the foreground "melt" with the floor because they're of similar color.

Maybe you can try to darken the base/the plinth of the foreground counters or perhaps make the floor a bit darker so that the counters come a bit to the fore. I would do that in post.

 

Don't worry too much about log or photographic exp., from my experience it doesnt' make too much difference, someone correct me if I'm wrong.

Most of the time I personally use photographic exp.

 

I agree with Brian, half the battle's won in post, especially when doing architectural competitions with short deadlines.

 

When your project is finished and you got some spare time, take a look at

render elements -> object ID ("object color" and "enable filtering" switched on).

This one renders out a seperate pass containing 3DSMax Object-colors.

Assuming you assigned every object in your scene a different object-color, you can use this layer in PS to select every single object in your rendering by color within a second.

7.50am here in germany, high time for a coffee!

 

Regards, Lutz

[mienq.blom]

Im not sure if this is the "technical correct" way, but this is how i do it anyway (i work with vray, not mental ray).

Darken the refraction colour of the glass to get rid of the bright washed out direct sun. Then add additional lights (invisible) just on the inside of each window. This way you can fake realism, but have complete control of the brightness and direction of the light source.

Im not sure which light you would use with mental ray. I normally use the vray plane light, so its the exact size and shape of my window and I can decide whether to have light reflect off both sides or only 1.

i duno.. maybe giv it a try?

I never change my scene settings according to light sources. I finish my scene settings with global illumination only.. and then adjust my light sources and camera settings accordingly.

[ivanjay]

The last image you posted looks much better.

If you got some time left, you could try tuning some of the colors - to my opinion there's a bit too much beige in your picture.

The counters in the foreground "melt" with the floor because they're of similar color.

Maybe you can try to darken the base/the plinth of the foreground counters or perhaps make the floor a bit darker so that the counters come a bit to the fore. I would do that in post.

 

Don't worry too much about log or photographic exp., from my experience it doesnt' make too much difference, someone correct me if I'm wrong.

Most of the time I personally use photographic exp.

 

I agree with Brian, half the battle's won in post, especially when doing architectural competitions with short deadlines.

 

When your project is finished and you got some spare time, take a look at

render elements -> object ID ("object color" and "enable filtering" switched on).

This one renders out a seperate pass containing 3DSMax Object-colors.

Assuming you assigned every object in your scene a different object-color, you can use this layer in PS to select every single object in your rendering by color within a second.

7.50am here in germany, high time for a coffee!

 

Regards, Lutz

 

I do agree on the color scheme, however this is an existing conditions thing. We are modifying existing counters.... Final gather got 80% through its hi res scan and I had to cancel since this needs to get to the farm. Going now!

[Jennifer]

The Log exposure control adds a gamma of 2.2 to the output of your image, so output gamma should not also be used with that control. The mr Photographic control will add output gamma, too, if you do not have gamma enabled and is smart enough to not double-gamma correct and disable its own gamma when gamma is set in Preferences.