Heterogeneous participating media tests

[OnoSendai]

Will this only be available to people who know ISL?

Hi Neo,
At some point I plan to do some stuff to make ISL easier to use, as in make a Gui interface to controlling the parameters. So underneath it will still be ISL, but it should be usable by non-programmers.

[OnoSendai]

More to read as why wouldn't you wanna allow that. Is there a side effect you want to avoid?

Well, it's just that allowing curved paths would make things a lot more complicated, although I guess you would decompose said paths into a piecewise linear approximation.

[OnoSendai]

Test with a shader modifying the scattering coefficient.
The medium is enclosed in a cube in this scene - it's the shader that defines the spherical region in which the scattering coefficient is greater than zero:

Code: Select all

def eval(vec3 pos) vec3 :
	vec3(
                if(
                  dist(pos, vec3(0.0, 1.5, 1.5)) < 0.6,
                  2.0,
                  0.0
                 )
	  )

[BBjam]

Is there any chance you could add support for 3D textures, or some kind of volumetric data sets?
I'm thinking of what one would need to get a fluid blending sim, say from Real Flow, into indigo.

[CTZn]

Exciting, Ono ! Would that eventually collapse into a star (ie will volumetric emission happen) ?

Just found:

http://www.custard.org/~andrew/visualization/datasets]
http://www9.informatik.uni-erlangen.de/External/vollib/

http://www.vizworld.com/tag/volume/ (for its first article/OT)

[OnoSendai]

Volumetric emission may indeed happen at some point.

[OnoSendai]

Is there any chance you could add support for 3D textures, or some kind of volumetric data sets?
I'm thinking of what one would need to get a fluid blending sim, say from Real Flow, into indigo.

Yup, support for 3d volume data sets would be cool. The main issue I have with volume datasets is that there doesn't seem to be a standard file format for them, so it's a bit hard to know which format to support.

[CTZn]

Indeed. Maya uses an own binary voxel cache, period. But parameters are accessible per voxel

Would be cool if Indigo had a pipeline for voxels later, because fluids/liquids are based on a finite voxel container in most apps supporting them (ie 10x25x25. blender, Maya and I suppose 3dxMax and C4D).

Nice voxels interpolation (Hermite?) would be Indigo...

Just speculating

Meanwhile those volumetric parameters and upcoming improved ISL accessibility are great great news Ono !

[OnoSendai]

A new test:
The clouds are done with a scattering medium, where a FBM ISL shader controls the cloud density.

[Musorgki]

Thats cool!

[OnoSendai]

In this image, a volumetric shader is controlling the absorption of the glass medium.
It's basically a continous blend between three different absorption colours.
The medium looks like this:

Code: Select all

<medium>
        <name>MedIndigo Material_mid0</name>
        <precedence>10</precedence>
        <basic>
            <ior>1.600000</ior>
            <cauchy_b_coeff>0.000000</cauchy_b_coeff>
            <absorption_coefficient>

              <shader>
                <wavelength_dependent>true</wavelength_dependent>
                <shader>
                  <![CDATA[
                  
                    def col(real t) vec3 :
                    
                      if(
                        t < 0.5,
                        lerp(
                          vec3(100.0, 100.0, 1.0), # blue
                          vec3(1.0, 100.0, 100.0), # red
                          smoothstep(0.25, 0.35, t)
                         ),
                         lerp(
                          vec3(1.0, 100.0, 100.0), # red
                          vec3(1.0, 1.0, 100.0), # yellow
                          smoothstep(0.65, 0.75, t)
                         )
                        )
                      
                     def eval(vec3 pos) vec3:
                         col(e2(pos) * 6.0)
                         
                         # + fbm(pos * 100.0, 6) * 0.5
                  ]]>
                </shader>
              </shader>
            </absorption_coefficient>
        </basic>
    </medium>

[Zom-B]

now please a sponge bob render with this technique
A feature for the 2.2 branch or above?

[OnoSendai]

This stuff is for the 2.4.x series (next series after 2.2.x)

[neo0.]

^
This is really cool. Maybe we could get access to some basic shader presets through the UI.. I have always really wanted to see a shader for creating bumpy water (without the need for bump maps.)

As for the clouds.. really neat stuff! Any possibility of getting a full blown atmospheric system with things like atmospheric scattering.

[suvakas]

That glass render looks awesome !!