problem with mental ray lighting

[cakewalkr7]

I asked this on the WIP board, but so far no responses, so hopefully someone here might know. I'm just getting started learning arch viz and this is the first scene I've tried to create (in max). I worked through the mental ray lighting/final gather tutorials included with max and it seems straight forward enough. The examples they gave worked as illustrated, but when I tried to apply the same or similar settings to my scene, it's extremely dark and I'm not sure why. My scene consists of a daylight system with an mr sun and mr sky using final gather, logarithmic exposure set to brightness:65 and exterior daylight checked off. In the 3ds tutorial, there weren't any other lights used, yet the room was very well lit... is there a reason why I'm not getting more light through the glass in my windows and doors? Thanks!

[pixelperfectg]

Try this:

1) Delete your current light setup.

2) Change the renderer to scanline, then back to mental ray to reset any changes to the default setting.

3) Add a daylight system and target your windows with the sun.

4) Change the sun to a mrSun

5) Change the sky to a mrSky and click yes when it asks to create the physical sky for your environment.

6) Enable log. exposure control and turn on the exterior daylight option.

7) Enable FG and use the draft preset. Set the FG bounces to 3.

8) Render.

9) If the light levels look ok in this preview, then increase your FG settings manually or by using one of the higher quality presets.

 

If that doesn't light your scene then check these:

1) Is your sun aimed properly.

2) Is you scene scaled properly? For example, ensure the building isn't a mile long or anything like that.

3) Make sure you glass material is configured properly. You should be using the new A&D material for pretty much everything.

 

That's just an ultra basic workflow because it doesn't use photons. If you want to use GI photons along with FG, then the workflow listed above would inclue this:

6.1) Turn on GI photons only (not FG) and tune your photons.

7.0) Enable FG and use just enough FG samples to smooth out the solution.

 

Jeff

[cakewalkr7]

To scale? Hmmm.... it was all based off of guessing the dimensions of an interior photo. My units are set to feet w/ fractional inches.

[cakewalkr7]

Thanks Jeff, I tried all of that and it was still pretty dark. I then hid the house and created a box with a big window cut out just to see if perhaps I didn't have enough window space in my original to let enough light in. Even with a larger opening, it still didn't light it up much. I then turned off the daylight option in logarithmic exposure and turned down the brightness to 25 and that lit it up considerably. So, then I went back to my original house and tried it again. It was better, but I ended up adding 2 interior fill mr omni lights. Thanks for your help!

[John Dollus]

The exterior daylight option is mainly for exterior renderings as it uses a different color mapping scale. If you are rendering interiors, you want to turn it off and set your max level somewhere around the same value as your brightest light source.

[cakewalkr7]

Thanks John, that helps clarify things. There seems to be sooooo many ways to do something in max that it's hard to get my head wrapped around which way is the best/most efficient. Thanks again.