Sassy lights in mental ray

[alias_marks]

Hello all. Wow! I'm having trouble finding out why mental ray is worth it. I'm having some trouble getting my lighting right and thought some of you may have some pointers. I've posted an image of what I've got so far. Mostly what bothers me is that I'm not getting a good varaion in shadow ranges from the objects that are in the foreground vs. the objects in the background.

 

I am also having touble getting my brightness up below the roof without washing out the roof on top. It seems like my variation/falloff in shadows is way off all around and I can't seem to change the right settings.

 

I'm also getting this weird light glow under the soffit even thought there are no lights under there.

 

Any ideas?

 

I've posted a sample images and my light/render settings. I'm using all mental ray - DGS materials with 3ds max bumps

 

 

 

Render Settings (sorry about image resolution, photobucket is acting up)

 

Light Settings (I know my multipliers are set fairly high, when I set them down to 1 or 2 I end up with a completely dark image)

 

 

Thanks for looking and any ideas you may have.

 

Michael

 

*edit - changed resolution size of render settings image

[Justin Hunt]

Use FG Fall-off. This limits the effect FG samples influcing object that are far away

 

Akso dont be afraid to use 1m+ photons and 1000+ photons per sample. Give the samples to work with. Set a sample radius to something relevant to the scene scale .This in turn will let you lower the FG samples to under 50

 

Use the Indirect illumination settings of each light to tweek. Use Manual rather than automatic. The energy can be set higher to get more light into the deep areas, rather than increasing the intensity. Decay is the energy fall-off , Typically I use between 1.7 and 1.5 and start with 50000 GI photons and go up, I have gone up to 2m without much hit on render time and got fantastic results.

 

JHV

[aaron-cds]

Exteriors with mental ray are easy - trouble free. Check out the exterior mr tutorial to get started http://lakehao.home.comcast.net/ Start with the settings in the tutorial and experiment from there.

 

The problem that you're having is your decay is set to inverse square. Set it to none and change the multiplier back to 1 - 2. The skylight multiplier is about 25 times too high as well. That should make a difference.

[alias_marks]

Great tips, thanks for the help. I found that tutorial very helpful and if anyone else reading this thread wants to check out another great exterior mental ray tutorial, I highly recommend this one by qball. He really goes in and explains reasons for picking certain settings over others.

 

He also goes into a good ammount of detail discussing the settings to use when doing test renders vs. final renders.

 

Here's a progress shot of where I've been able to go after taking your suggestions into account and going throught the tutorials.

 

 

Turns out the biggest mistake I was making was having the "exterior daylight" box checked in the environment settings. I just had it left over from scanline, but it turns out mental ray works way better without it.

 

Now on to tackle materials.

 

Thank you

 

Michael

[aaron-cds]

Now if you really want my 2 cents . . .

 

Unless you're going for that overcast day look, you're shadows are way too blurry for a sunny day and not blurry enough for a completely cloudy day.

[Thiago de Andrade]

i agree with Aaron. Try also using only FG with exterior scenes, MR is very fast for exterior scenes, and also in an overall context, the photon bounces were also too high on the first config. I think you've discovered it on your tutorials, huh? If you're using logarithmic exposure control, don't be affraid to increase the number of contrast and middle levels.