Author Topic: Windstream  (Read 15037 times)

Offline bigben

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Re: Windstream
« Reply #30 on: September 19, 2007, 11:06:12 PM »
OK, I got very distracted last night just trying to get close to where you are....   Let's just say that I now have a far greater appreciation of what you have achieved so far   ;D

That left my morning train ride to refocus, and unfortunately I forgot to save often ;)

Nevertheless I did manage to split up the image map into it's white and non-white components so that we can start to tinker with the border of the image map without affecting the rest of it.  I'm not entirely convinced that this is going to be a big fix, and will probably be only useful in situations like yours where your clouds are fairly close to being what you want.

The biggest problem with masking clouds is the thickness of the cloud at the edge of the mask. If it's almost full thickness then you have a very odd looking cloud. The only way around this might be to break up the border with another fractal of smaller scale but this will still be of limited use... If however you're relatively close to having the right result then the additional border breakup may provide a subtle improvement that makes just a bit more believable...

I'll attach this morning's work although all it does is isolate the different parts of the image map. The zip file contains my test image so you probably don't need it.  I'll persist with this test regardless of how well it progresses with clouds because it will be useful to me for my river masks

[edit] It would be really nice if there was an additional input in the cloud node that scaled the cloud thickness based on a value from another node. That would open up a lot of possibilities for creating different cloud formations without trying to mask the cloud fractal. Easy to say... possibly not that easy to program  ;) [/edit]
« Last Edit: September 19, 2007, 11:10:31 PM by bigben »

Offline Lucio

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Re: Windstream
« Reply #31 on: September 20, 2007, 02:30:30 PM »
Thank you bigben, I'll have a look on it

This could be also a good occasion for me to learn something about functions :) I will try to apply your masking technique to some graphic result. Thank you very much!

PBauba: I've seen your image. I like very much how you worked over the bottom part, I think it's compositionally much better than mine. The superior part is also very nice but is a bit too 'illustration-like' and it's not the mood I wanted. However thank you very much and great work :)

Offline bigben

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Re: Windstream
« Reply #32 on: September 20, 2007, 11:09:07 PM »
I had a few more problems which I need to test more to isolate the exact causes.  I thought I was using some fairly stanard blending of shaders but I ended up with the flat masked result at the top and bottom of the cloud layer and nothing in the middle (when viewed from below). This disappeared completely when I moved the camera above the cloud layer.... kinda weird but it may have been my fault.  I'm going back to my earlier cloud masking tests (which still work) and will try and combine the two.  If you could email me a clip of a single cloud layer with any masks (images not required) I can try and fit it in with what you're doing.

Offline Lucio

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Re: Windstream
« Reply #33 on: September 21, 2007, 11:21:37 AM »
I had a few more problems which I need to test more to isolate the exact causes.  I thought I was using some fairly stanard blending of shaders but I ended up with the flat masked result at the top and bottom of the cloud layer and nothing in the middle (when viewed from below). This disappeared completely when I moved the camera above the cloud layer.... kinda weird but it may have been my fault.  I'm going back to my earlier cloud masking tests (which still work) and will try and combine the two.  If you could email me a clip of a single cloud layer with any masks (images not required) I can try and fit it in with what you're doing.

bigben, your technique works very good. I'm testing it in different ways and also given me some idea on how to expand it. I'm trying to go on something concrete, and soon I'll let you know :)

Offline BPauba

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Re: Windstream
« Reply #34 on: September 21, 2007, 11:31:27 PM »
Hey lucio, what is your email? I can send the image right now if you would like...

Offline Lucio

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Re: Windstream
« Reply #35 on: September 21, 2007, 11:51:04 PM »
Oh, thank you! You can send it at usciouscio@yahoo.com

Thanks again :)

Offline bigben

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Re: Windstream
« Reply #36 on: September 23, 2007, 11:52:05 PM »
bigben, your technique works very good. I'm testing it in different ways and also given me some idea on how to expand it. I'm trying to go on something concrete, and soon I'll let you know :)

I wasn't entirely sure how useful it would be for you as it would largely depend on the type of image you were using and the method used to apply extra breakup of the edges. Glad to hear you found it useful.  :)

Offline Lucio

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Re: Windstream
« Reply #37 on: September 24, 2007, 10:27:13 AM »
Your technique gave me new ideas and I've got some result. Here's a simple shader structure I elaborated for masking clouds directly in TG2. I piped in a 'subtract colour' node a density fractal and an inverted greyscale mask. Here's a test render



As you say the hardest part of the work is to get decent detail from border blending. Now, this render looks horrible because it's just a test done with a unappropriate image mask but potentially this technique could bring good results, if you got a fine greyscale tuning of the mask borders. I've alleged a .zip file with the .tgd and the image mask so you can continue the work on it if you want.
Now as a next step I would like to integrate your technique to get some extra-detail from border blending. I'm also thinking about a method that could connect surface layering with cloud masking, even if it's not very simple. Thank you! :)

Regards,

Lucio

Offline bigben

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Re: Windstream
« Reply #38 on: September 25, 2007, 12:54:35 AM »
I'll have a play with this.  I was thinking along the lines of using an inverted border mask as well so that you gradually subtract more detail from the masked cloud border as you move out to the edge of the cloud

If you want to save some memory for TG to work with convert your mask image to greyscale and save it as LZW compressed TIF. The compression only saves space storing the file, but using greyscal instead of RGB will make a significant difference to memory usage which you may need for objects etc...

Also... if you're using a broad blur on your mask you might also experiment with smaller images as the internal AA applied to images in TG will act as a good blur for low res images. It largely depends on what level of fine detail you need in your mask. You can also use a colour adjust shader to counter some of the AA on low res masks if it becomes too blurred.

Offline Lucio

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Re: Windstream
« Reply #39 on: September 25, 2007, 01:16:16 PM »
Thanks for your hints bigben. I'm discovering step by step the world of functions and I'm amazed by the further possibilities offered by this extremely powerful instrument :)

If you looked at my .tgd maybe you noticed that my masking technique scatters many undesired 'cloud fragments' all over the scene. I reworked on it utilizing some of your concepts and now I've got a method that completely cleans the contour of the masks. Take a look at the new .tgd I've alleged here. Here is another test render





Now this masking method is complete and should work fine. It's a possibility. You can build your cloud layers directly in TG2 as you want, then mask and reshape them in all the ways you prefer. I'll try to utilize it in some of my next works. A bad aspect is that on the other side it seems to slow down significantly rendertimes. I'll do some specific test to see the effective increase.

If you find anything that could improve it or something alternative please let me know! :)

Regards,

Lucio
« Last Edit: September 25, 2007, 01:20:43 PM by Lucio »

Offline Lucio

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Re: Windstream
« Reply #40 on: September 25, 2007, 01:18:55 PM »
Hmm got a bit off topic.. maybe I should post that in the shared files section

Offline rcallicotte

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Re: Windstream
« Reply #41 on: September 25, 2007, 01:34:14 PM »
Who cares?  This is cool.
So this is Disney World.  Can we live here?

Offline bigben

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Re: Windstream
« Reply #42 on: September 25, 2007, 11:45:40 PM »
I played around with this for a while to figure out the best way to build what I was thinking of.  Some approaches sounded OK in theory but didn't work... but in the end I got there (in theory) without complicating things too much. Render times are noticeably longer, but not as excessive as I have seen in previous masking experiments.

 I rearranged the placement of the image map a little but not for any great reason other than that's one way I normally do it  ;). The colour adjust is also not essential.  I use it for tweaking the mask for testing and sometimes leave it in.  The surface previews were also left in from testing. I find it quicker to look at those to get a feel for what's going on instead of waiting for the cloud.

All of that aside, the only thing it really does is subtract a second cloud fractal from the cloud, gradated from the the edge of the mask inwards. The only extra tweak then is the settings of the second cloud fractal. I hope it works.. or at least gives you some more ideas  :)