Experimenting with Vortex shader to make a storm cell cloud system

[Darknight]

Hey guys,
I have been struggling for the past few days trying to make a storm cell cloud system. These are the renders I have got going so far. All low resolution test renders, but will give you the idea of what I wanted to make.






Some suggestions on how to make something that looks more like this image I am posting below would be very helpful.

[bigben]

Damn you.  I haven't played with the vortex shader yet and now I want to test out some ideas far simulating a cold front.

First thing I can suggest is that the storm in the photo isn't really a vortex. You're really only looking at one arm of a vortex a long way from the centre.  For that, you'd need a much bigger vortex.

[Darknight]

Good pointer. I have been trying some more techniques to get this, will post soon. One thing I simply do not understand is, how can I get the vortex shader to spiral downwards? That way I can get the clouds to form a column.

[choronr]

NWDA has a tornado pack which might give you what you need.

[Darknight]

But unfortunately NWDA has not come back online yet.

[choronr]

But unfortunately NWDA has not come back online yet.

I would think that Danny Gordon is now working at bringing the site back up soon.

[Dune]

You would need to use the altitude offset function, which adjusts the underside (by default). Add a cloud fractal in and see what happens. For a column you would need very high cloud (or more layers, perhaps localized), and use the altitude offset function to bend the area around the column up, like with a smooth simple shape. In the alti offset function, black will be 'deleted' for the number of meters you enter, white will do nothing, AFAIK. So if cloud layer is 400m thick, enter 400m and there will be no cloud anymore, enter 200 and black will 'raise/delete' cloud for 200m from the underside, so to speak.
As it happens, I was just experimenting with this; see new post 'ominous sky'. 

[Tangled-Universe]

You would need to use the altitude offset function, which adjusts the underside (by default). Add a cloud fractal in and see what happens. For a column you would need very high cloud (or more layers, perhaps localized), and use the altitude offset function to bend the area around the column up, like with a smooth simple shape. In the alti offset function, black will be 'deleted' for the number of meters you enter, white will do nothing, AFAIK. So if cloud layer is 400m thick, enter 400m and there will be no cloud anymore, enter 200 and black will 'raise/delete' cloud for 200m from the underside, so to speak.
As it happens, I was just experimenting with this; see new post 'ominous sky'.

Yes that's the idea, kind of...I'd do it the other way around though, also using the depth modulator.

1) Create a thick cloud, say 4000 metres and for sake of this example choose an altitude of 2500 metres.
2) Localize your cloud, use default settings
3) Create a constant scalar and set it to a value of 1 and connect it to the density shader input port of the cloud node.
4) Create a constant scalar with a value of 0.2 and connect that to the depth modulation input port of the cloud node.
    Now your cloud is 800 metres thick, because 0.2 x 4000 = 800.
5) Set the "Centre 0...1" value to 0.8.
    The setting of 0 means that the underside of the actual cloud layer is at the exact bottom of your principle cloud layer.
    The exact bottom is at "cloud altitude - (cloud depth/2)", thus 500 metres.
    Setting the "Centre 0..1"value to 0 will result in a 800 metre thick cloud ranging from 500 to 1300 metres altitude.
    Setting the "Centre 0..1" value to 0.8 will result in a 800 metre thick cloud ranging from 3700 to 4500 metres altitude.
6) Create a soft (20-50%) circle of 2000 metres with a simple shape shader and set the centre the same as the localized cloud centre.
    Connect this as altitude modulator to your cloud
7) Use negative values for the altitude modulation to let the simple shape shader's circle create a dip/pit in the cloud layer.
    Theoretically, if white = 1, then the altitude modulation can be set to a maximum of -3200 metres in this example.
    The centre of the circle would     be just at the bottom of the principle cloud layer.

[Darknight]

Thanks guys. Some great pointers here! I have to run to the airport to pick up some family and will be back  by afternoon to try out the techniques you have mentioned here. I am excited to try these out!

[Darknight]

You would need to use the altitude offset function, which adjusts the underside (by default). Add a cloud fractal in and see what happens. For a column you would need very high cloud (or more layers, perhaps localized), and use the altitude offset function to bend the area around the column up, like with a smooth simple shape. In the alti offset function, black will be 'deleted' for the number of meters you enter, white will do nothing, AFAIK. So if cloud layer is 400m thick, enter 400m and there will be no cloud anymore, enter 200 and black will 'raise/delete' cloud for 200m from the underside, so to speak.
As it happens, I was just experimenting with this; see new post 'ominous sky'.

Yes that's the idea, kind of...I'd do it the other way around though, also using the depth modulator.

1) Create a thick cloud, say 4000 metres and for sake of this example choose an altitude of 2500 metres.
2) Localize your cloud, use default settings
3) Create a constant scalar and set it to a value of 1 and connect it to the density shader input port of the cloud node.
4) Create a constant scalar with a value of 0.2 and connect that to the depth modulation input port of the cloud node.
    Now your cloud is 800 metres thick, because 0.2 x 4000 = 800.
5) Set the "Centre 0...1" value to 0.8.
    The setting of 0 means that the underside of the actual cloud layer is at the exact bottom of your principle cloud layer.
    The exact bottom is at "cloud altitude - (cloud depth/2)", thus 500 metres.
    Setting the "Centre 0..1"value to 0 will result in a 800 metre thick cloud ranging from 500 to 1300 metres altitude.
    Setting the "Centre 0..1" value to 0.8 will result in a 800 metre thick cloud ranging from 3700 to 4500 metres altitude.
6) Create a soft (20-50%) circle of 2000 metres with a simple shape shader and set the centre the same as the localized cloud centre.
    Connect this as altitude modulator to your cloud
7) Use negative values for the altitude modulation to let the simple shape shader's circle create a dip/pit in the cloud layer.
    Theoretically, if white = 1, then the altitude modulation can be set to a maximum of -3200 metres in this example.
    The centre of the circle would     be just at the bottom of the principle cloud layer.

I was following along until I hit a wall trying to look for the "Center 0..1" variable. Where is that located. I am using TG3 and I can only see these parameters. Did you mean the "y" axis value of "Center"?


Meanwhile, I tried another method using an image map shader to drive the cloud Density and got some promising results. Not yet there obviously but it did let a few bulbs light up around my head.

[Tangled-Universe]

The settings for "altitude offset" "depth modulator" and "centre 0...1" are in the Functions tab of the cloud layer.

Good luck!

[Darknight]

The settings for "altitude offset" "depth modulator" and "centre 0...1" are in the Functions tab of the cloud layer.

Good luck!

You are the man! thanks Martin

[Darknight]

You would need to use the altitude offset function, which adjusts the underside (by default). Add a cloud fractal in and see what happens. For a column you would need very high cloud (or more layers, perhaps localized), and use the altitude offset function to bend the area around the column up, like with a smooth simple shape. In the alti offset function, black will be 'deleted' for the number of meters you enter, white will do nothing, AFAIK. So if cloud layer is 400m thick, enter 400m and there will be no cloud anymore, enter 200 and black will 'raise/delete' cloud for 200m from the underside, so to speak.
As it happens, I was just experimenting with this; see new post 'ominous sky'.

I tried something based on your logic and it seems to give me some what of a result that I am looking for. Just one question though, is there a way to tilt the vortex plane? Man I wish I was better at math..Terragen seems to be way more powerful in the hands of a skilled mathematician!
These are my trials.

[bigben]

Some interesting results. The image map version may not be exactly what you were after but it's a nice cloud formation all the same.

[Darknight]

Some interesting results. The image map version may not be exactly what you were after but it's a nice cloud formation all the same.

True that. It was indeed a happy accident I feel that maybe I can use the image map method to have a background layer and then make the core using the vortex method and then try and see how they look when layer one over the other. I donno I am really just going crazy with this now...but loving every second of it! Posting one more variant. This time I reversed the vortex direction.