Atmopheric scattering in blender

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fbrunell
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Atmopheric scattering in blender

Post by fbrunell » Sun Apr 13, 2014 10:57 am

Blender 2.70
Blendigo 3.6.17.0
Indigo 3.6.18

Can anybody out there gives me a hint on how to produce a scene in Blender with Atmospheric Scattering? I have searched everywhere within past posts and the manual and can't find anything.

Even searched on that error message (the one at the bottom) on the World Wide Internet.

I mean, what I am trying to do is pretty simple...

- A scene with a box in the middle,
- A sphere all around my scene (BIG sphere)
- A specular material on the BIG sphere with Atmosphere as the medium type

That's it and I am always getting the following error message :

"Scene parsing error: could not find element 'center'. (In element 'atmosphere', around line ..."

What, where, when, why the heck do I get that center element in the scene from Blender.... It's been driving me nuts for the past couple of weeks...

Thanks in advance,

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yonosoy
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Re: Atmopheric scattering in blender

Post by yonosoy » Sun Apr 13, 2014 11:13 am

Hi.
The way atm is to assign an atmosphere material externally.
Atmosphere need a center of reference that is not implemented in blendigo.
Also there is a lack of understanding in GUI since a real one need a value of 7 digits and only accept 6.

The sphere needs a radius of 6458135 m. and to be placed in 0,0,-6378135 m. (perfect sphere).
Then your scene needs to start at 0 m. Hope is all.
Thanks in advance.

EDIT: also extra-atmospheric sun and Path Tracing Simple is required.
EDIT 2: in GUI, the center accepts the min value of -1000000 (7 digits, but needs -6458135. (there are other ways: to center the universe in the center of the Earth (value of atmospheric center 0,0,0))...
Last edited by yonosoy on Sun Apr 20, 2014 11:16 am, edited 3 times in total.
"... the hamster don't see the wheel, and this wasn't said before." (yoS eidaN "el Olvidao")
"... nor 0.2 galaxys, nor 0.8 little chikens ..."

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yonosoy
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Re: Atmopheric scattering in blender

Post by yonosoy » Mon Apr 14, 2014 1:39 pm

<atmosphere>
<center>0 0 -6378135</center>
<turbidity>2</turbidity>
</atmosphere>


In the GUI, setup a specular material with the atmosphere medium applied. Save it in the HDD.
Open it with a text editor and in the section <atmosphere> change the <center>... line as shown above.
In blender, put a sphere of 6458135 meters of scale in the point z=-6378135 and assign to it a external material (the first of the list). Link the atmosphere material saved in the HDD and give to it the same name that the material has (it is shown near the box of name).

The scene starts at 0 m of heigth (universal center).
If helps it is possible to reproduce Ono's atmospheric example inside blender with the material linked, just say it.
Thanks, bye.
"... the hamster don't see the wheel, and this wasn't said before." (yoS eidaN "el Olvidao")
"... nor 0.2 galaxys, nor 0.8 little chikens ..."

fbrunell
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Location: Quebec, Canada

Re: Atmopheric scattering in blender

Post by fbrunell » Mon Apr 14, 2014 4:33 pm

Ok, I got something... Not sure what but I think I am going somewhere... I'll have to play with it a little bit more...

Thanks Yonosoy... your post helped me getting started...

StompinTom
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Re: Atmopheric scattering in blender

Post by StompinTom » Wed Apr 16, 2014 4:03 am

Perhaps it could be an environment option, so that the atmosphere sphere is automatically created for you? It would be great to be able to define a custom radius as well, for atmospheres (planets) of different size...

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yonosoy
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Re: Atmopheric scattering in blender

Post by yonosoy » Wed Apr 16, 2014 4:30 am

Hi.
The atmosphere medium is the Earth atmosphere.
Only works in this range 6378135-6458135 (80 km.).
The feeling is that this center is there for "to do the trick": (to use a little box over the scene instead of the complete atmosphere sphere)...
An environment option that consider the placement and dimension of the atmosphere is a nice option.
For other planets ... custom atmospheres (so hard...).
The beautiful part is to define the custom atmospere with the meaning of "density" (less concentration in altitude), No idea ...

EDITED with the right range values... :)
"... the hamster don't see the wheel, and this wasn't said before." (yoS eidaN "el Olvidao")
"... nor 0.2 galaxys, nor 0.8 little chikens ..."

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Oscar J
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Re: Atmopheric scattering in blender

Post by Oscar J » Sun Apr 20, 2014 10:05 am

Fully agree witty Tom, if atmosphere should be useable for normal users. Manually creating those spheres, well...
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zurkdahool
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Re: Atmopheric scattering in blender

Post by zurkdahool » Wed Sep 16, 2015 7:39 pm

Thanks to the advise from yonosoy in the de-couple thread i stumble over to this thread. The explanation from yonosoy is very good. Because i am working on the medium stuff in blendigo i will see what i can do with the atmosphere. It should definitely be an easy 'enable atmosphere' button exists...

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zurkdahool
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Re: Atmopheric scattering in blender

Post by zurkdahool » Wed Sep 16, 2015 8:32 pm

amazing ... i understand the atmosphere feature :-) thanks to yonosoy! i have tested it to setup manually in blendigo without any external editing (textfiles...) and it looks good to me:
blendigo_atmosphere.png
'Automatic atmosphere setup' in blendigo is possible. Have to think about the implementation...

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Oscar J
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Re: Atmopheric scattering in blender

Post by Oscar J » Thu Sep 17, 2015 6:57 am

Awesome.

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zurkdahool
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Re: Atmopheric scattering in blender

Post by zurkdahool » Sun Sep 20, 2015 3:57 am

zurkdahool wrote: 'Automatic atmosphere setup' in blendigo is possible. Have to think about the implementation...
Atmosphere is now out of medium panel and moved to world panel as 'atmosphere feature':
atmosphere.png
How it works:
Enable atmosphere will add empty sphere (Indigo Atmosphere). This is just for imagination... When exporting the scene to indigo the sphere, specular material and atmosphere medium will added automatically. After export the sphere will be deletet (not implemented yet as you can see in the screenshot :-) )

StompinTom
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Re: Atmopheric scattering in blender

Post by StompinTom » Mon Sep 21, 2015 9:17 am

Very nice! Like the option of being able to relocate it in the Advanced tab.

Is this in the git repo? Should I be keeping up to date with that?

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Oscar J
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Re: Atmopheric scattering in blender

Post by Oscar J » Mon Sep 21, 2015 9:24 am

Tom, have a look in his post here (scroll down):http://www.indigorenderer.com/forum/vie ... 2&start=45

So yes, looks like there might be some great stuff added there in a while.

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