Problem with milk and glass

mrCarnivore · Post by **mrCarnivore** » Sun Mar 11, 2007 5:40 am

I'm trying to render a glass of milk since it seems like these are kind of in nowadays.

I would like to achieve a result like this:
http://www2.indigorenderer.com/joomla/f ... light=milk

But I have some problems: I followed the modeling instructions for fluid in a glass from here:
http://www2.indigorenderer.com/joomla/f ... .php?t=637

And I used the milk material from here:
http://www2.indigorenderer.com/joomla/f ... 88eb0#9018

The glass material I use is this:

Code: Select all

	<medium>
		<name>GlassMedium</name>

		<precedence>10</precedence>
		<basic>
			<ior>1.50</ior>
			<cauchy_b_coeff>0.0</cauchy_b_coeff>
			<absorption_coefficient_spectrum>
				<rgb>
					<rgb>0.5 0.5 0.5</rgb>
				</rgb>
			</absorption_coefficient_spectrum>
		</basic>
	</medium>


	<material>
		<name>GlassMaterial</name>

		<specular>
			<transparent>true</transparent>
			<internal_medium_name>GlassMedium</internal_medium_name>
		</specular>
	</material>

My problem is this: The bottom of the glass looks way too white which is very unrealistic. Also the milk is just too white...
But have a look yourself:

neepneep · Post by **neepneep** » Sun Mar 11, 2007 5:57 am

How big is your model in blender?

mrCarnivore · Post by **mrCarnivore** » Sun Mar 11, 2007 6:19 am

When I press N in blender, the dimensions of the left glass are:
DimX = 0.20
DimY = 0.20
DimZ = 0.34

so it seems to be 20 cm long doesnt it? shall I reduce the size?

EDIT: The result doesn't really change when I reduce the size to DimX = 0.08..

Post by **OnoSendai** » Mon Mar 12, 2007 6:26 pm

Make sure the precedence of the glass medium is higher than that of the milk medium.

8bstudio · Post by **8bstudio** » Mon Mar 12, 2007 9:00 pm

Try to use for the glass these settings:

Code: Select all

<medium>
      <name>GlassMedium</name>

      <precedence>10</precedence>
      <basic>
         <ior>1.50</ior>
         <cauchy_b_coeff>0.0</cauchy_b_coeff>
         <absorption_coefficient_spectrum>
            <rgb>
               <rgb>0.0 0.0 0.0</rgb>
            </rgb>
         </absorption_coefficient_spectrum>
      </basic>
   </medium>

mrCarnivore · Post by **mrCarnivore** » Mon Mar 12, 2007 9:17 pm

@OnoSendai: With higher you mean lower numer, right? So the glass medium is supposed to have a lower precedence number than milk?

@8bstudio: I think making the glass even whiter would be counterproductive, wouldn't it?

Post by **OnoSendai** » Mon Mar 12, 2007 9:27 pm

heh, no, when i say higher, i mean a higher value.
Yes, i know this contradicts the CS convention, but meh.

nik

8bstudio · Post by **8bstudio** » Mon Mar 12, 2007 9:29 pm

mrCarnivore wrote:I think making the glass even whiter would be counterproductive, wouldn't it?

I saw in many post that completly transparent glass have rgb absorption coefficient = 0 0 0. I you use a rgb 0.5 0.5 0.5 maybe is grey glass!

In my test for glass with rgb 0 0 0 normaly I get good result! Try to see my last post for example
http://www2.indigorenderer.com/joomla/f ... 2&start=30
You can try!

Post by **OnoSendai** » Mon Mar 12, 2007 9:34 pm

absorption 0.5 0.5 0.5 is very slight absorption (mean path length on the order of 2m)

8bstudio · Post by **8bstudio** » Mon Mar 12, 2007 9:43 pm

Maybe I wrong with glass rgb = 0 0 0 because with Indigo v0.6 I used those!
I try me too with 0.5 0.5 0.5!

Post by **OnoSendai** » Mon Mar 12, 2007 9:50 pm

The units changed from Indigo 0.6 to 0.7.
The units of absorption changed from mm^-1 to m^-1

mrCarnivore · Post by **mrCarnivore** » Mon Mar 12, 2007 9:54 pm

Thx for the help. Hope I'm seeing better results with the higher precedecy value.

Problem with milk and glass

Problem with milk and glass

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