Author Topic: Nebulae  (Read 27402 times)

Offline Denis Sirenko

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Re: Nebulae
« Reply #210 on: April 10, 2018, 09:16:44 PM »
Thanks!

This is so fascinating. I have to say, that to my taste it doesn't look like a space nebula as much as it did before, but nevertheless gets more and more interesting.

Hannes, this is an interesting moment for me. Could you tell me more precisely what exactly makes the last nebulae less natural than before? And the word "before" - with which old nebula, for example, do you compare? This is an important point, because over time, the vision is lost and criticism is needed.

Regarding the file, in fact I can not show too much, but I can now share the clip-file of the main form.

Offline WASasquatch

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Re: Nebulae
« Reply #211 on: April 11, 2018, 12:54:31 AM »
Thanks!

This is so fascinating. I have to say, that to my taste it doesn't look like a space nebula as much as it did before, but nevertheless gets more and more interesting.

Hannes, this is an interesting moment for me. Could you tell me more precisely what exactly makes the last nebulae less natural than before? And the word "before" - with which old nebula, for example, do you compare? This is an important point, because over time, the vision is lost and criticism is needed.

Regarding the file, in fact I can not show too much, but I can now share the clip-file of the main form.

Thanks for the share! I think I understand where those shapes are coming from finally.
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Offline luvsmuzik

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Re: Nebulae
« Reply #212 on: April 11, 2018, 01:01:28 AM »
yes! Thank you for this share! I think what most of us were doing was using the Density Fractal preceding our warps for our cloud layer. I had tried some warps but could not get the opacity you achieved with your large fractal warps. Terrific stuff!

I will continue to experiment adding the Density Fractal back in, masking the warps, anything else I can fiddle with, but thanks again!  :)

Offline WASasquatch

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Re: Nebulae
« Reply #213 on: April 11, 2018, 02:00:47 AM »
yes! Thank you for this share! I think what most of us were doing was using the Density Fractal preceding our warps for our cloud layer. I had tried some warps but could not get the opacity you achieved with your large fractal warps. Terrific stuff!

I will continue to experiment adding the Density Fractal back in, masking the warps, anything else I can fiddle with, but thanks again!  :)

I was stuck using much smaller scales (especially smallest scale), and single PF warpers, which only push vertically, creating noise. Honestly surprised I never thought of the redirect shader after the vertical warp discussion. The 3 axis redirection is what is specifically creating the small scale detail as it basically simulates small scale cloud build up by being warped.
« Last Edit: April 11, 2018, 02:03:50 AM by WASasquatch »
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Offline Dune

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Re: Nebulae
« Reply #214 on: April 11, 2018, 05:36:29 AM »
Thanks very much, Denis. It'll be interesting to see how you achieved your wonderful work.

Offline Kadri

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Re: Nebulae
« Reply #215 on: April 11, 2018, 05:48:39 AM »

Thanks for sharing Denis. Had no time to look at the file but i will for certain :)

Offline Denis Sirenko

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Re: Nebulae
« Reply #216 on: April 12, 2018, 09:35:37 AM »
I'm glad that it can be useful. I hope that someone will be able to improve this and achieve more realistic results. I still do not like everything in this network.

I was stuck using much smaller scales (especially smallest scale), and single PF warpers, which only push vertically, creating noise. Honestly surprised I never thought of the redirect shader after the vertical warp discussion.

WASasquatch, this is all strange, because:

About details: I have a cloud 15 kilometers in size, made specifically to be able to receive small parts. I think I have no problems here. Even on the contrary sometimes the details too small)

As for the problem with vertical stretching of clouds - both ways that I offered in this topic work:

You should either use the Redirect Shader method or the Vector Displacement Shader method, but not both.

I forgot to mention that you need a Build Vector node if you use the Vector Displacement method.

Use one of the following methods, but not both.


Method 1 - Redirect Shader:

Use 3 fractals that generate displacements. Connect fractal 1 to the 'X' input of the Redirect Shader, connect fractal 2 to the Y input, and connect fractal 3 to the Z input. The Redirect Shader is now producing 3D displacement (vector displacement). You can then use this as a warper for the Warp Shader.

Fractal 1 (disp) --\
Fractal 2 (disp) --> Redirect Shader --> Warp Shader
Fractal 3 (disp) --/


Method 2 - Build Vector and Vector Displacement Shader:

Use 3 fractals that generate colour or greyscale. Connect fractal 1 to the 'X' input of the Build Vector, connect fractal 2 to the 'Y' input, and connect fractal 3 to the Z input. Connect the Build Vector to the 'Vector function' input of a Vector Displacement Shader. The Vector Displacement Shader is now producing 3D displacement (vector displacement). You can then use this as a warper for the Warp Shader.

Fractal 1 (colour) --\
Fractal 2 (colour) --> Build Vector --> Vector Displacement Shader --> Warp Shader
Fractal 3 (colour) --/


Method 1 is simpler for your needs because there are fewer nodes and conversions. But Method 2 is simpler if you already have a vector to use as displacement, e.g. if you have a vector displacement map, where you don't need to use a Build Vector.

Matt

The 3 axis redirection is what is specifically creating the small scale detail as it basically simulates small scale cloud build up by being warped.

I do not think that this is due to small details. The main factor that allows to obtain small details is a combination of factors such as the size of the cloud and its density (as far as I could understand it). And, of course, the presence of small-scale details in the fractal sent to the warper.
« Last Edit: April 12, 2018, 09:44:41 AM by Denis Sirenko »

Offline luvsmuzik

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Re: Nebulae
« Reply #217 on: April 12, 2018, 02:13:11 PM »
So now I am wondering if method 1 and method 2 suggested by Matt can be merged if you do not apply displacement with the build color method. I shall soon see.

Offline Denis Sirenko

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Re: Nebulae
« Reply #218 on: April 12, 2018, 03:47:09 PM »
The first attempts to reconcile the new nebula with TG colors and my stars (Photoshop).


Offline Hannes

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Re: Nebulae
« Reply #219 on: April 12, 2018, 04:32:33 PM »
Hannes, this is an interesting moment for me. Could you tell me more precisely what exactly makes the last nebulae less natural than before? And the word "before" - with which old nebula, for example, do you compare? This is an important point, because over time, the vision is lost and criticism is needed.

Hi Denis,
I was referring to these ones:
https://planetside.co.uk/forums/index.php/topic,23403.msg246588.html#msg246588

Don't get me wrong, they look absolutely stunning! But they are so extremely crisp, that they might look like something else (no idea what, but I like it!). Even more like particle simulations.

The following ones are again very much like Nebulae, so I guess, you're on the right track.

Offline Hannes

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Re: Nebulae
« Reply #220 on: April 12, 2018, 04:33:28 PM »
..and thanks a lot for the share of course!!!!

Offline j meyer

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Re: Nebulae
« Reply #221 on: April 12, 2018, 05:52:37 PM »
Yes, thanks for sharing the file.
Never tried a contrast of 50 myself, interesting. :)

Offline Denis Sirenko

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Re: Nebulae
« Reply #222 on: April 13, 2018, 04:17:46 PM »
Hi Denis,
I was referring to these ones:
https://planetside.co.uk/forums/index.php/topic,23403.msg246588.html#msg246588

Don't get me wrong, they look absolutely stunning! But they are so extremely crisp, that they might look like something else (no idea what, but I like it!). Even more like particle simulations.
The following ones are again very much like Nebulae, so I guess, you're on the right track.

Ah, I understand you. Thanks for the comment. Yes, "crisp" is a very suitable word. Minor details are needed, but not so. On the last render, I reduced them.

Yes, thanks for sharing the file.
Never tried a contrast of 50 myself, interesting. :)

Yes, I had to install this to get long thin ridges. But you can and less. The desired effect appears already somewhere from 15-20 and more.

As for the variations in total cloud forms in repetition similar to the Crab Nebula, I would imagine your original shared idea of using a base density fractal, and than separate warping passes and fractalization would create the variation needed. Especially a final large warp for those "lag" features if the the fractal warp shader with roughness turned down a bit doesn't create it. I'm actually working on a project with similar uses in order to create variance, but be on "track" with the whole form, while using the original form for each new element. It also also adjustments to all passes (cloud nodes) a bit easier without having to look into multiple density shaders.

WASasquatch, I did not quite understand what you are offering. Could you elaborate, or in other words describe what you are proposing?

I tried today to achieve the effect of "blowing light clouds off the surface of heavy ones" with the help of a fractal warp shader and came to the conclusion that it does not provide any additional capabilities, compared to using an input or merge warp shader in combination with a power fractal shader. He is even capable of a little less. But, it seems, it is more productive.

Offline WASasquatch

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Re: Nebulae
« Reply #223 on: April 14, 2018, 07:45:15 PM »
I do not think that this is due to small details. The main factor that allows to obtain small details is a combination of factors such as the size of the cloud and its density (as far as I could understand it). And, of course, the presence of small-scale details in the fractal sent to the warper.

On the contrary, your initial example clip setup has a smallest scale almost 5x the base scale. The warping creates "holes" (in a terrain this would look bad) in this base form, while pushing them, creating build up along the edges of the wholes, creating that small scale debris details. I attached a image that shows these low level plumes that build up and capture light

Quote from: Denis Sirenko date=1523525737
WASasquatch, I did not quite understand what you are offering. Could you elaborate, or in other words describe what you are proposing?

I tried today to achieve the effect of "blowing light clouds off the surface of heavy ones" with the help of a fractal warp shader and came to the conclusion that it does not provide any additional capabilities, compared to using an input or merge warp shader in combination with a power fractal shader. He is even capable of a little less. But, it seems, it is more productive.

I'll attach a simple TGD of what I mean.  Give me a moment.
« Last Edit: April 14, 2018, 08:00:10 PM by WASasquatch »
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Offline WASasquatch

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Re: Nebulae
« Reply #224 on: April 14, 2018, 08:45:04 PM »
Here is a very simple example of varying repetition. You won't really see in it the render as the area we're looking at really has no really definition but what the cloud layer is forcing in due to extreme contrasts, but take a look at the last merge shaders preview.

There is clear repetition, but no shape is the same. Adding further warping, translation distances, can improve this method.

Edit: added some test renders with different seeds, and doing another at smaller scale, but will take longer.
« Last Edit: April 15, 2018, 08:39:47 AM by WASasquatch »
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