Fog and beams

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Marcel2586
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Joined: Sat Mar 05, 2016 7:42 am

Fog and beams

Postby Marcel2586 » Sun Jul 03, 2016 6:50 am

Fog, Beams of dust and dancing dust particles in the sun.
We all have seen it and we know it should be there, if you see a picture, movie or game, somewhere it will show up.
But why we see them at only certain circumstances.
It has al to do with with light overpowering, washing out the effect.
Look at the moon in the middle of the summer, you can't see it, the daylight is overpowering the moonlight, But we all know it is still in the sky.
When it is darker, or we have closed almost shut a curtain, you will see the moon, beams and dancing dust particles.
Fog is mostly dramatic in the early morning, the sun is not strong enough to burn the fog away.
If you do a google on fog, you will find a lot of pictures taken just after sunrise, when you have pockets of fog over grass fields and over here in the Netherlands near ditches. Funny, 9 out of 10 pictures have grazing horses in it.
All well, you would say, but it can be misty the whole day! Yes it is, but it is something different, they are low hanging clouds touching the ground.
Or if you live near the coast, you could have fog from the sea. The water temperature is higher than the air above it and you have no wind at all, it is creating mist/fog

To make fog and beams is not that hard.
You only need to know how to set it up.
This is all Reality setting, so it works for Poser and Daz Studio.

tunnel.jpg

Here an example, Stonemason's Our Lost Future

How to set up fog
Make a primitive box in Studio or Poser, we will turn this in Reality into a container to hold the fog. The box itself will not be visible but the fog inside it will be visible.
Now that we have a box we need to make it visible, to do that we need a light.
I will use for this a spotlight, create one and position it left and above the box.
Rotate it on the Y axis -90 and on the X axis -15.
fog_box_setup_1.jpg


Now open Reality.
Go to materials tab and open the cube by clicking on it.
Now on the default glossy, right click and choose To Null.
fog_box_setup_2.jpg


Now click on the "Volumes" button with the cloud in it.
This will open another screen.
Now click on the button "Add new volume"
Underneath Air you will see a new volume with the name "<New volume>"
Under Name you can change the name of the volume, call this "Fog"
Now a tricky part, when you push enter, the newly created volume is not selected.
Click on it so it is selected. Now click on the selection box ""Scattered" so it is selected.
Change the Scattering color to a very dark color. It will not change the color of the fog, but it tells Luxrender the density to use. So black is no fog and white is full force. As we need a subtle fog we give it a color of 006, 006, 006
fog_box_setup_3.jpg


Now go back to the materials tab.
As you have may noticed, you have only one option for the cube material and that is Volumes.
Click on Volumes.
You will see two boxes, one Inner volume box and one Outer volume box.
Select in the Inner volume box Fog.
fog_box_setup_4.jpg


Now start the render.
fog_1.png


As you can see, it is not the most spectacular picture, but it shows you how it works.
So we have made a Box and told Luxrender that it is a container for our fog (To Null)
We have made some fog atmosphere for the box container, it was filled with the fog.
We had placed a light to make the fog particles visible.

Sun beams!
Start a new scene and add 2 or 3 cylinders give theme some angle
Make a floor and wall.
Ad a top mesh light and set the cylinders to "To null" and give them a fog inner volume
No start to render.
Be very careful with this, we forse Luxrender to do things that is not possible in real life.
by rotating the beam/cylinder we force sunlight to a angle. if there are objects poking trough the beam, it will cast a shadow down and not following the beam. So use this in open spots. Make a render and look where the sun is hitting the ground and place there fog Cylinder containers.
beams_1.png


Here's My 3D Dust particles
It is saved as .obj and you have to import it as .obj
I am still figuring out the best settings for it, but i used it with the first picture above "Tunnel"
The material was set to architectual glass and the object was scaled up.
use it as you see fit.
The object was split over two rar files as it was to big to upload it in one go.
Use Winrar to unrar the files.
Attachments
Dust.part01.rar
(4.77 MiB) Downloaded 322 times
Dust.part02.rar
(4.03 MiB) Downloaded 330 times
Last edited by Marcel2586 on Sun Jul 03, 2016 3:12 pm, edited 8 times in total.
this would be funny if it weren't happening to me :shock:

pciccone
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Re: Fog and beams

Postby pciccone » Sun Jul 03, 2016 8:22 am

Wow, Marcel, thank you for another wonderful tutorial.
--
Paolo

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Marcel2586
Posts: 438
Joined: Sat Mar 05, 2016 7:42 am

Re: Fog and beams

Postby Marcel2586 » Sun Jul 03, 2016 11:23 am

You are very welcome Mr. Ciccone and it is fun to make.
this would be funny if it weren't happening to me :shock:

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Kimberly58
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Joined: Sun Apr 27, 2014 12:52 am

Re: Fog and beams

Postby Kimberly58 » Mon Jul 04, 2016 12:19 am

I thought I would give this a try. I did not use the particles provided by Marcel in this image.
Attachments
07-03-16scatter.jpg

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Marcel2586
Posts: 438
Joined: Sat Mar 05, 2016 7:42 am

Re: Fog and beams

Postby Marcel2586 » Mon Jul 04, 2016 3:38 am

Really nice Kimberly
this would be funny if it weren't happening to me :shock:

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Kimberly58
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Re: Fog and beams

Postby Kimberly58 » Mon Jul 04, 2016 10:34 am

With Marcel's permission, I created a PDF of this tutorial for easy downloading.

Here is the link for Sigstan's, "Light Strategies in Luxcore" tutorial.
viewtopic.php?f=23&t=492

Fog and Beams.pdf
Revised document 7-10-16
(666.57 KiB) Downloaded 295 times

Gederix
Posts: 104
Joined: Tue Mar 01, 2016 11:06 am

Re: Fog and beams

Postby Gederix » Mon Jul 04, 2016 11:20 pm

So what did you mean by leaving the shutter open for 4 days to get the tunnel image? Would you mind posting your settings and explaining how you set up the scene? Not to be a pain... :)

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Marcel2586
Posts: 438
Joined: Sat Mar 05, 2016 7:42 am

Re: Fog and beams

Postby Marcel2586 » Tue Jul 05, 2016 4:58 am

Attachments
tunnel setup 3.jpg
tunnel setup 4.jpg
tunnel setup 2.jpg
tunnel setup 1.jpg
this would be funny if it weren't happening to me :shock:

Gederix
Posts: 104
Joined: Tue Mar 01, 2016 11:06 am

Re: Fog and beams

Postby Gederix » Tue Jul 05, 2016 11:06 am

Ok interesting, thanks!

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Fram1963
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Joined: Tue Mar 01, 2016 1:52 pm
Location: Ottawa, Ontario, Canada

Re: Fog and beams

Postby Fram1963 » Tue Jul 05, 2016 2:00 pm

Kim... maybe it would be a good idea to add the new setup info for the tunnel image to the PDF you so nicely created!

Thanks again,
Lyne
:D


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