Mental Ray/Image Based Lighting & the Daylight System?

[Brad_S]

Hi all-

I am new to this forum and pretty new to 3DS Max, though I've been trying pretty hard to get myself up to speed.

 

I do Design Visualization in an architectural firm and am trying to teach myself 3DS Max, a daunting task to say the least.

 

I use 3DS Max 2008 with Mental Ray and have had pretty good luck using the daylight system for my exterior images. One of the issues I have run into however is trying to get a realistic clouds while using the daylight system. I have tried creating physical clouds using atmospheric apparatus helpers using the fire effect and the fog effect but inevitably the clouds come out black...they work great without the daylight system, but I'm partial to this system and would like to keep using it. I'm not against using a dome if I have to but again I have had difficulty figuring out how to get the dome to work with the daylight system.

 

I thought HDRI's would possibly be the answer but I am again running into issues where the sky looks great but I loose all shadows and depth to my image. I have to crank up the brightness in my environment just to see the building at all.

 

I have been struggling to find good tutorials on hdri's and image based lighting that deal with mental ray specifically and the daylight system.

 

Basically, if anyone can help me figure out how to get clouds in my daylight system it would be Soooooo appreciated!

 

I think the answer is in Image Based Lighting with HDRI's, but I'm open to all ideas.

 

Thanks for your help on this-

 

Brad S

[Macer]

Heres one option:

 

http://mentalraytips.blogspot.com/2007/02/clouds-with-mental-ray-sky.html

 

Its a non hdri option but with a bit of experimentation it works well.

 

For hdri in MR checkout:

http://www.mentalboutmax.co.uk/Html/training/MentalRay/HowTo/index_MR_Ht.html

 

Good luck.

[fzappa]

Clouds with mental ray sky

 

http://mentalraytips.blogspot.com/2007_02_01_archive.html

[Brad_S]

Thanks for the reply Macer-

 

I checked out Zap's site and I am familiar with the process of placing the image file in the haze control of mr Sky but I haven't had really good results, the image always comes out...well...too hazy. Yellowish and moody. The video on his Web site shows some pretty good cloud effects but I have yet to be able to reproduce this yet.

 

I will check out the Mental 'bout Max video if I have to, although I would always prefer to take some free advice if I can get it y'know. I can't help thinking I must be missing something otherwise there would be a lot more people having the same issues that I am having.

 

Thanks again

-Brad

[Justin Hunt]

A nice way to get the haze to work is to separate the skylight from the physical sky in the backround. ie turn off inherit from skylight.

 

You will need to play with the output values of the sky map to get it to look right. Also try using the Non physical scale if your using the photographic exposure control

 

If you want to go the dome route then the rayswitch shader is what you will need to work with FG and GI. Check out Jeff Pattons blog for instructions, you may need to search the archive for the article http://jeffpatton.cgsociety.org/gallery/

 

JHV