Light Streams through Scattering Medium

[Don Cheke]

I am trying to get light streams though a scattering medium. I have a spotlight coming through the windows, the lighting mode for the environment is set to interior. I have used a large box for the fog scattering medium. Any ideas? The first image below shows they are not happening. The second image is an old scene from a different render engine, showing what I would like to achieve. The third one shows the light streams applied in PhotoShop.

[designgestalt]

hello Don,
sorry, it is hard to say something without more information....
it seems like you are on the right path so it seems, it could only be a matter of adjusting the values.
but we need to see a bit more of your settings or maybe it is possible for you to share a .ksp!

cheers
designgestalt

[Don Cheke]

hello Don,
sorry, it is hard to say something without more information....
it seems like you are on the right path so it seems, it could only be a matter of adjusting the values.
but we need to see a bit more of your settings or maybe it is possible for you to share a .ksp!

cheers
designgestalt

Thanks for having a look. The link is to DropBox (121MB). I brightened the scene and did get some of the light pattern effects on the floor and upper deck, but did not get any rays through the scattering medium. https://www.dropbox.com/s/4lltrjp76qyew14/Barn%20Interior.ksp?dl=0

[Don Cheke]

Nobody can help? I did supply the file in the last post link.

[designgestalt]

hey Don,
sorry for not coming back to you any earlier...
the virus caught us here as well, we are not infected (yet) but the kids cannot go to school anymore and a lot of things with my clients have to be sorted...
so I only had very little time to briefly take a look into your scene...
as far as I can tell, it has to do with your lighting situation: the lights in the barn are very bright and in general there is a lot of light in your scene. I assume you cranked up the lights to achieve the volumetric effect and also to achive the window reflection on the floor. this seems to be contraproductive to the volumetric lights, but to make a valid statement, I would have to investigate further and try out a few more things!
also that 50000 watts spotlight outside of the barn seems a bit too much
(as usual..   ) there is a very good and tight tutorial from Esben out there, that might help you setting up your scene!
https://www.youtube.com/watch?v=SdyypYcK8EU
I would start like this, with a spotlight right behind the window, adjust your scattering media and spotlight and than add more lights to the scene!

I am sorry, there is not much more I can do for you at the moment, my machine is currently running 24/7 to crank out some work to bring in the harvest before everything shuts down!

cheers
designgestalt

[Don Cheke]

hey Don,
sorry for not coming back to you any earlier...
the virus caught us here as well, we are not infected (yet) but the kids cannot go to school anymore and a lot of things with my clients have to be sorted...
so I only had very little time to briefly take a look into your scene...
as far as I can tell, it has to do with your lighting situation: the lights in the barn are very bright and in general there is a lot of light in your scene. I assume you cranked up the lights to achieve the volumetric effect and also to achive the window reflection on the floor. this seems to be contraproductive to the volumetric lights, but to make a valid statement, I would have to investigate further and try out a few more things!
also that 50000 watts spotlight outside of the barn seems a bit too much
(as usual..   ) there is a very good and tight tutorial from Esben out there, that might help you setting up your scene!
https://www.youtube.com/watch?v=SdyypYcK8EU
I would start like this, with a spotlight right behind the window, adjust your scattering media and spotlight and than add more lights to the scene!

I am sorry, there is not much more I can do for you at the moment, my machine is currently running 24/7 to crank out some work to bring in the harvest before everything shuts down!

cheers
designgestalt

Thanks, I will check it out. I did get that high value for the lighting from another online tutorial and I did try many variations of lights and scene before posting for help.

[Don Cheke]

Looks like the spot light needs to be within the scattering medium as well for this to work.

[designgestalt]

that is not really necessary...
it is more depending on the spreadangle of your light beam and the distance of the lightsource to the scattering medium.
the wider the angle the more it washes out the effect, and also with the distance of the lightsource to your medium the falloff spreads and the intensity decreases. please take a look at the attached images ...

[davidolo]

Hi!, i have the similar problem when i choose interior mode  but when i change to product i can see the fog  but the render takes a lot of time. do you know why?
thankas!!