View Single Post
Old June 19th, 2008   #6 (permalink)
pixelperfectg
Senior Member
 
Join Date: Dec 2003
Location: SC, USA
Age: 38
Posts: 206

Name: Jeff Patton


United_States 


Default Re: interior swimming pool, caustics problem

Quote:
Originally Posted by daveb867 View Post
thanks for the response jeff however i'm not familiar with a caustic projection map.
You use a bitmap of a caustic pattern in the projection map of a light source. Take a look in your 3dsmax/maps/lights folder, you'll see an example caustic projection map named "caustic.gif". There's also instructions on using projection maps in the help file under the topic of "advanced effects rollout" of light sources.

Quote:
Originally Posted by daveb867 View Post
i have however attached an image of the effect i want to achieve
The reflective caustic pattern on the ceiling? Hmmm, I may be wrong here, but I don't think you'd actually see caustics like that in a similar 'indirectly lit' real world scenario. If the sun were actually hitting the water then yes I'd imagine a strong, pronounced caustic pattern like this would be visible.

For example, here's a few similar real world photos of indoor pools I found on a quick google search. I'm not seeing such a strong/pronounced caustic pattern on the ceilings:
http://www.lakeviewrise.com/DSCF0043.JPG
http://456js.co.uk/Images/SwimmingPoolB.jpg
http://image012.mylivepage.com/chunk...20pool%207.JPG

I know the point of your question isn't whether or not the reference image caustic pattern is physically accurate. It's that you simply want a caustic pattern to reflect from your swimming pool. I only mention the point about reality because once you solve the "no photons stored" issue in your scene, if photon caustics don't show up (or they aren't powerful), this may be why.

I could be completely wrong in my assumption here, but I think the person that created your reference render used a caustic projection map since that strong/clear pattern doesn't seem natural to me with the amount of sunlight in that room...so you may want to focus on that route.

A while back I remember seeing a few tileable caustic patterns on some website. I'll dig through my bookmarks to see if I saved it.
__________________
Jeff Patton
My mental ray blog | Personal Website | mrmaterials.com
pixelperfectg is offline   Reply With Quote