Iceberg

[Stur]

For once, let's try to finish a project.
As I don't have many free time, and as a noob modeler, I thought to myself it would be easy to render an iceberg.
I was so wrong !
My aim was to get something close to this famous picture :

After many trials, I'm still far from it.

Here is where I'm at at the moment. I know, the iceberg model is crapy and not smoothed. I will do a better one later, for the moment I try to get convincing materials. I have only two materials, but it's hard.

Any hint about materials is greatly welcome.
(I tried CoolcolJ's tabulated datas for water, but I only got a deep black. Maybe a model size problem ?)

[neo0.]

It almost looks like some of the lighting from the surface is being transmitted through and emitted from the bottom..

[PureSpider]

But... you DO know what SSS does, don't you?

[neo0.]

I thought sss doesn't actually cause light to exit a medium, it just bounces around? Oh well, if that's not it, I guess you were right.

Anyyhooww, it could be the water material too. Maybe try cutting back on the absorption..

[zeitmeister]

I think the problem could be the varying thickness and scattering of the ice.
I don't have a clue how you could solve this with a simply on-surface geometry.
Maybe a 3D, volumetric noise could be the solution to vary the sss inside the iceberg?

[Stur]

Thx for comments.

We can do volumetric noise in Indigo ? I'll have to investigate.

Anyway I had serious troubles with 1.1.18. I'll post a render this evening. With 1.1.17 things look ok but with the latest free version, the background turns to black, the water is near black too and the iceberg looks like a mesh emitter with a lot of multicolor noise.

[Stur]

Sorry for double post, just to show the weird result with Indigo 1.1.18.

The scene is included in case someone would be interested to test it with the 2.0.x versions.

Regards.

[Stur]

Sorry for triple post (not my fault if no one is intrigued by this behavior )

I finally tested it with 2.0.6, and here is the result. The scene is the same than the one rendered with 1.1.14 and 1.1.17

I can understand that some SSS values has to be changed since previous versions of Indigo, but not that way. Even the sky is black.

Am I doing something wrong ? Is it a known bug (in which case I'm sorry not to have found the mention to it in the forum)

Thx.

[OnoSendai]

It's not a known bug, but the behaviour certainly looks incorrect. I'll have a look at it at some point.

[CTZn]

Hey Stur, for your scene you really want to use a secondary light bottom up like suggested by neo0.

The water IOR seems not to be in the UI, I suppose it's around 1.334 ?

[Stur]

Oh, indeed there seems to be a little bug in my screencap. Yes, water's IOR is 1.33.

About your first sentence, I didn't understand neo0 suggested me to add a light bottom up. Maybe I could, but then it wouldn't be physically accurate.

But honestly, I wonder if the "reference" picture I posted is really physically accurate itself. I wonder if it is not heavily postprocessed.

[Doug Armand]

But honestly, I wonder if the "reference" picture I posted is really physically accurate itself. I wonder if it is not heavily postprocessed.

I think you'll find that image is actually an illustration. Taking an image like photographically would be impossible in one shot.

[neepneep]

I made an iceberg too, but its not a very nice one - it just wants to sink ships and doesn't give a flying fart if children are on board.

[Stur]

Hey !
I'm jealous ! How did you do the water ?
The water is very cool, and the iceberg just need a higher resolution and a better material.

I have plans to use ISL for my iceberg scene, that's why I paused my project to learn ISL. But, the water was a pain too for me.

Did you use a very large cube for water ? Did you use SSS for water ? Did you use a displacement map for waves or are they modeled ?

Thx.

[neepneep]

I tried using a couple Blender displacement modifers with cloud textures for the waves but because of the high poly count it slowed the rendering down a lot. I ended up using Indigo's displacement on the top face of a massive cube (much much much much faster) and made in photoshop (basically make a new layer->render clouds->gausian blur 100px->find edges->set layer to multiply-> and then repeat 3 or 4 times but lower the gausian blur by about 25px each time)
It still needs a bit of fiddling because there are supposed to be larger waves too.

Sea water material is just simple water with slighly more R absorption and a smidgen of SSS.

I also had to use an "air cavity box" (simple box with transp. spec. material, 1.00 IOR and a higher precedence than the sea material) and placed it where the camera is so that the front face is just in front of the iceberg and the entire FOV is through the front face - that way it chops the displaced water nicely and cleanly.

Any suggestions on a good iceberg mat?