[martgreg]

i am trying to make a bottle filled with a liquid similar to mouth wash or car coolant.. but it always comes out really dark.ie not very clear only the edges show the color of the liquid everything else is balck

i am using standard material from database with slight change in color

any help would be appreciated

[Bubbaloo]

Sounds like a tweak in the attenuation is needed.

[martgreg]

I have tried that with a little bit of success .. i am gonna re read the details on attenuation and try again....

I can do it ifi put my mind to it .... sesame street said so ...

[lsega77]

Remember that the thickness of your geometry plays a direct role in how your material reacts to light with regard to transparency/attenuation.

Let's say you have a 10cm thick box. If you set your attenuation distance to 20cm your result will be more a clearer version of your transmittance color. Setting your attenuation to 1cm will hardly let any light escape at all (more than likely appearing like a black shiny material).

Optimally you'll want your attenuation distance somewhere between 1/2 the thickness of your geometry to 1.5 times thickness (IMHO) to transmit your color. In this case, if we set the attenuation distance to 5cm, we'll begin to see the transmittance color as it's being controlled by the ND of your material.

Luis

[martgreg]

thanks i will try that.. I will measure my the thickness of each part .. and teh liquid filler...

i will post some results hopefully when i get some time

[Mihai]

Be careful with setting your transmittance always by how thick/thin your models are. A certain type of glass is the same material, not matter what object it's applied to. If you want to simulate a 30cm thick glass block, then to get realistic results, you don't change the attenuation distance. It's supposed to be darker, the thicker the object is. It's the same material.

There can also be huge differences in attenuation between different types of glass, for example common grade glass has an attenuation distance of about 3cm while optical grade glass having much less impurities has an attenuation distance of about 5m.

You can try changing the transmittance also, if your glass isn't clear enough. This is a pretty sensitive parameter, and it needs to be pretty bright for the material to be almost clear, around 235-245.