Global medium help needed

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Solo
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I have seen some inspiring renders lately where global medium have been used to create fog or god rays, I am at a total loss as to how it is done. Is there a tutorial for achieving this with the Presto MC engine?

I normally never use post processing but fog has been the only real PP I have a need to do using depth maps, however if i could achieve this directly with Thea4SU (yes i'd like to avoid studio too) I'd be completely PP free.
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nigec
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you can't do global medium in SU, only a medium box which is REALLY scene dependent and may not work that well with Presto MC

Its way better in Studio along with relight, then you can adjust light sources
Personally I've given up and use a position pass and depth, its so much faster and can be composed in PS quickly
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Hieru
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+1 For a tutorial.

I can't wrap my head around global medium or medium boxes either. I've tried using settings and example scenes posted on the forum, but as soon as I apply them to my own scenes everything goes pear shaped.

It doesn't help that I don't understand what each setting controls or what the values mean.
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Solo
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I have been playing with .png clouds and gradients to create foggy scenes, not bad, renders fast, still wish i had a better solution.
whitehall fog-Scene 3.jpg
whitehall fog2-Scene 3.jpg
setup fog.jpg
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Rosco
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I'm not completely sure about this, but I think since some revision the "medium box" way is not working as before.
For sketchup It seem that the only way to get fog is keeping the camera out of the medium box. Actually the effect is the same, as fog or any medium should not be visible at very short distance from camera, so if it starts 10cm or 1m away from it the result is basically equal.
The only con is the need to move the fog box for different shoots.
This sample (fast - interactive MC) is made with a 100x100x50m box placed "near" the camera. Material is set with 0.02 for scatter density and 0.002 for absorption density, but it depends on the lighting.
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fog.jpg
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JQL
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Yup, The idea of putting that on front of camera is not so good. However I've seen solo asking for a camera plugin in Sketchucation, wich he found. So I'm imagining he just found a smart way of creating medium attached to camera...

Am I right? Very nice Solo!
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BTW those boat renders are really really cool, I'm going to steal that png idea as soon as I have some opportunity
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Those foggy imes look pretty good, Pete. Clever technique too.
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Solo
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JQL wrote:Yup, The idea of putting that on front of camera is not so good. However I've seen solo asking for a camera plugin in Sketchucation, wich he found. So I'm imagining he just found a smart way of creating medium attached to camera...

Am I right? Very nice Solo!
You are, :mrgreen: . Still playing around, looking for best solution, will share if i succeed.
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nigec
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in studio you can set the camera to be contained in the box but it only works outside the box in thea4su

I think one of our former users used planes for fog and it looked quite nice, I've also seen them done with geometry and medium, I think dementia is kicking in coz I can't remember his name neither :oops:
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