Glass and liquid

[Finema]

Hi,
I've read a lot of things about glass and liquid and i don't find a precise answer.
I'm searching the best way to produce a glass containing wine.
In keyshot, i've 2 object :
the glass and the wine (little bigger)
For this moment, i use a simple material and choose Liquid and give a red color.
Indice refraction is 1.5
I play with Transparency (0,03) and Etalement Off to put an other color
Indice extern refraction is on 1
I would like to know if it's the good way or not ?
Thanks a lot.

[TpwUK]

Hi Fiema, if you have KS5 open the caustics.bip scene and see how it's done there.

Martin

[Finema]

Thanks Martin, but in caustic.bip, cognac material don't use liquid but dielectric. Why ?

[KeyShot]

That is in order to specify the interface between cognac and glass. The light would not refract properly if the transition was from cognac into air and then from air into glass.

[Finema]

thanks Keyshot but in caustic.ip cognac material is also dielectric and no Liquid.
Can i have the .obj glass of cognac in order to see how the three objects are contract ?
Thanks

[TpwUK]

Hi Finema, play with one i did a couple of years back ... https://grabcad.com/library/part-filled-tumbler

Martin

[Finema]

thanks TpwUK
but there is only 2 object ? different of caustic.bip and the bottom of the glass is empty

[Finema]

on this image :
the glass on the left use dielectric material, on the right > Liquid material
i dunno

[TpwUK]

Hi Finema - There are two ways to model a transparent object such as glass and the liquid within.

First way is the way I modelled that tumbler where the top of the liquid trims the inner surface of the glass and that trimmed surface then unites with the top and becomes the liquid. Using this way you can use the Fluids material.

Second way is to model the liquid and the container as two separate solids. If you have used this method of modelling then you will need to Dielectric for the reasons outlined by KeyShot.

Hope this helps to clear things up for you

Martin

[Finema]

Thanks a lot ! it's very clear now.

[Finema]

a last thing...
In the Caustic.bip :
glass cognac object is close or open ?
glass cognac object touch glass air ?
cognac air object touch glass air ?
cognac air object touch glass cognac object ?
Have you a shame of this ?
thanks

[TpwUK]

Hi Cinema

After looking at the caustics.bip file more closely, I appear to have given you misinformation. The Glass in the caustics scene has been trimmed, if you turn off both cognac materials you can see the difference in the glass. I have been working on the theories given below for this kind of rendering for years.

(i) I can see the ray travel theory as .... Glass --> Air --> Cognac --> Air --> Glass

(ii) If the model parts were solids then ray travel would be .... Glass --> Cognac --> Glass

In all this time, I have never used Dielectric materials. However after reading the Dielectric Shader wiki page, it would appear that for ultra realism one would use the Dielectric material type that KS offers, and that it has nothing to do with the modelling method as in my previous post. So my apologies to all for assuming instead of studying.

So in short Finema, you can use either type of materials Fluid or Dielectric, but that the use of Dielectric will give much more accurate/realistic  results.

Many thanks KeyShot for educating me, and even more thanks Finema for raising the question and opening my mind

Merry Christmas to you all

Martin

[Finema]

Thanks Martin and Merry Christmas