View Full Version : glass and drink caustics scene problems

03 March 2006, 03:29 AM
I'm having a problem with getting the caustics from the drink and ice to show through the glass onto the table, can anybody help? Here's some images and the scene file.
max file (

03 March 2006, 11:25 PM
Funny just a couple of threads down we were already talking about this type of issue...

First have you done the tut supplied with max? These tutorials are an awesome resource they are your best friend...
(Specialized>Rendering>Mental Ray>Creating Refractive Caustics) If not, do it, disect it, it will help. :thumbsup:

Something to consider since it is a still image remove the internal geometry that come in contact with the fluid. Convert the lathe glass to and e-poly or e-mesh. remove the intersecting geometry. separate the top of the fuild from the sides of the fluid (create two seperate objects) then goto back to the max tuts and do:

(Specialized>Rendering>Mental Ray>Using Mental Ray Shaders & Mats.>Using the Dielectric Material Shader)

That will solve all of your problems. ;)

03 March 2006, 03:32 PM
Thanks I'll give it a try.

04 April 2006, 10:16 PM
I'm using this same tutorial to re-create the inkwell in my compass rose scene...but I can't figure out what settings I need to change in order to make the liquid ink inside dark and very barely if at all transparent. Any ideas? I have three separate geometric pieces for the glass-air, ink-air, and glass-ink, along with three separate dielectric materials for each...but can't figure whats gotta change for each.

04 April 2006, 10:48 PM
Its kinda of wierd the color of the outside light persistance swatch of the ink-inkwell mat, will determine most of the color of the ink, but so does the light persistance (which AFAIK determines how much light is allowed to pass through the material) colors just barely off white make a huge difference (RGB 0.997,0.997,0.997 for instance)

edit: BTW make sure your other shaders are instances of the diffuse or your going to get some rather funky looking fluids (strange colors, artifacts, ect)

04 April 2006, 11:09 PM
I'll give that a shot...while I fool around with it, you have any suggestions for good color values for dark/deep brown ink?

Edit: You mean the photon dielectric being an instance of the surface dielectric? or are you talking about something else?

04 April 2006, 11:31 PM
Edit: You mean the photon dielectric being an instance of the surface dielectric? or are you talking about something else?


Gees as for color values, I mean it won't take much to get a dark color, probably start around 0.8, 0.8, 0.8 for your outside light, and something around what I stated above for the light persistance swatch. Your really going to have to play around with it, there are some really crazy color calculations going on... and I am by no means any kind of a master of them. Spent a week last year trying to make beer look like beer :p:banghead::D

04 April 2006, 11:46 PM
Yeah...I see what ya mean...I've rendered it 4 times (region renders only on the inkwell of course 4.5 minutes a pop) and I FINALLY got it to darken.

Here's my results:

-light persistance (.7, .7, .6)
-outside light persistance (.4, .4, .3)

-light persistance (.5, .4, .4)
-outside light persistance (black)

-light persistance (white)
-outside light persistance (black)

The above numbers are of course approximate as they are all 3 digits past the decimal...but all similar to brown...I could have copied the numbers but I would rather just click them somewhat close to each other ;) I don't think it makes too much difference does look better than the old renders though if I may say so myself...

04 April 2006, 03:57 PM
it looks waaay good, nice job:)

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