simple water material

[zeitmeister]

After experimenting around a lot,
I am looking for a simple water material. If you place objects with diffuse transmitter material applied inside a mesh (water) with a transparent specular material applied, the diffuse transmittance doesn't seem to be computed correctly.
Same with phong.
If you place this water mesh inside a glass mesh, everything looks much too dull.

Is there a way to create a material that causes refraction only, and lets all light rays pass through as they are?

Maybe it's an issue with indigo, because I don't think that it's realistic loosing all reflection and specular inside water?

[CTZn]

Hi zeitmeister,

I think that all materials using a medium (glass, liquids etc, namely specular and glossy_transparent) should not be in contact with others materials type at all. This is a case where the minimal possible distance should always be above the ray nudge distance, it is just me saying that, but please keep this as a rule of thumb !

I can nothing but stress users to refer to the documentation, some times at least:

Although it doesn't really have any exact physical basis, it could be thought of as the limit of many subsurface scatters inside a thin, highly scattering material. As such it should be useful for simulating such materials as curtains, lampshades etc..
It's meant to be used on single-layer geometry, and it does not have an associated internal medium (it's not an
interface material).

You must use either a specular or glossy material for what you want.

[zeitmeister]

This has been very helpful; thank you for pointing this out!
So I will have to do major changes to my materials inside my water mesh; keeping in mind only to use mediums in mediums (expect diffuse, I suppose).

[CTZn]

You are welcome zeitmeister, I am glad everytime I can help here.

Now I want to add this, a disclaimer per say:

What I said when I was not quoting the documentation (aka OnoSendai) was more a result of my feelings, resulting from an empirical experience at a given point in time, and under local conditions (a specific scene of mines), using older Indigo versions.

Only the documentation (OnoSendai) inputs can be taken as word since these topics are above the head of most people here, including me. That's what I was meaning with:

it is just me saying that, but please keep this as a rule of thumb !

Now, I believe that "interface materials" need to be able to inform Indigo wether a ray is inside or outside them, the contact with a "non-interface material" within might be the very cause of the issue you reported. But, this issue may arise only with transparent materials other than specular and glossy_transparent (I did never test another material blended with a null material within the (two) "interface materials" mentioned above, worth a try perhaps).

I can, and should not be more affirmative than this

[zeitmeister]

This is so strange... diffuse transmitter works perfectly inside a singel-sided mesh with specular material.
Or inside a double-sided mesh.
But not in both together.

Hmmmmmmm.

[neo0.]

Water is fairly easy :
»Set your material type to Specular.
»Set your IOR to 1.52
»If you want to go the extra mile, set your cauchy B coeff to about .003. This will produce more realistic results, but, in return, will also increase your render time.

Color should be a light blue. Also, set your absorbtion to something fairly low. Maybe 5%.

[zeitmeister]

I'm gonna try this, thanks!

[PureSpider]

Can you maybe post a screenshot of your scene setup that is bugging?
I have a hard time figuring out what it looks like.

And for the water... just use the material in the matDB?

[psor]

Water is fairly easy :
»Set your material type to Specular.
»Set your IOR to 1.52
»If you want to go the extra mile, set your cauchy B coeff to about .003. This will produce more realistic results, but, in return, will also increase your render time.

Color should be a light blue. Also, set your absorbtion to something fairly low. Maybe 5%.

*mooeeep* ^^ *ding*ding*ding*

Sorry, but wrong answer mate. The IOR of water is about 1.33382 not 1.52.


take care
psor

[Borgleader]

iirc 1.52 is glass

[pixie]

Hi zeitmeister,

I think that all materials using a medium (glass, liquids etc, namely specular and glossy_transparent) should not be in contact with others materials type at all. This is a case where the minimal possible distance should always be above the ray nudge distance, it is just me saying that, but please keep this as a rule of thumb !

Which can be a pain to model...

[Borgleader]

Hi zeitmeister,

I think that all materials using a medium (glass, liquids etc, namely specular and glossy_transparent) should not be in contact with others materials type at all. This is a case where the minimal possible distance should always be above the ray nudge distance, it is just me saying that, but please keep this as a rule of thumb !

Which can be a pain to model...

Actually i think in the case of water inside a glass, you can make the water mesh go into the glass mesh (above ray nudge) and use the precedence value to determine which will occupy the space.

In this particular case, i think Glass Precedence > Water Precedence is the way to go (I usually get the order mixed up and have to do it twice )

[psor]

I wonder if thats still an issue. Maybe Ono could do a little hack. Something like ... all non
medium shaders have a precedence of - lets say 1.000.000, just to be sure. Then it shouldn't
be an issue anymore. The question is, if it's possible at the moment with the code he has.
But it would rock big times to not worry about that anymore. ;o))

edit: And Ono, if you have to change the code a bit, maybe you can implement
something that makes it possible to "cut/slice" another object. Can't say it any better.
You know, to look through a wall for example without letting light in ...
Darn in that case my english sucks big times.


take care
psor

[pixie]

Hi zeitmeister,

I think that all materials using a medium (glass, liquids etc, namely specular and glossy_transparent) should not be in contact with others materials type at all. This is a case where the minimal possible distance should always be above the ray nudge distance, it is just me saying that, but please keep this as a rule of thumb !

Which can be a pain to model...

Actually i think in the case of water inside a glass, you can make the water mesh go into the glass mesh (above ray nudge) and use the precedence value to determine which will occupy the space.

In this particular case, i think Glass Precedence > Water Precedence is the way to go (I usually get the order mixed up and have to do it twice )

Imagine the water on a shore, then the rocks on the water, and the boats, and the beach, all without actually touching water... it's a nightmare came true

[Borgleader]

Imagine the water on a shore, then the rocks on the water, and the boats, and the beach, all without actually touching water... it's a nightmare came true

Why would you need to model all of it? You could just make your water mesh go under the "sea floor" and inside your boat (unless you actually see inside the boat)

Heres a "solid" suzanne mesh (diffuse mat) inside a water suzzane mesh (trans. spec. mat). I didnt not model around the interior one, i just duplicated it and scaled it up.