Sandstorm Arch - Finished

Started by old_blaggard, September 09, 2009, 01:12:49 AM

Previous topic - Next topic

Henry Blewer

The only thing I find is the hard arch edge. Aside from that, awesome pic!
http://flickr.com/photos/njeneb/
Forget Tuesday; It's just Monday spelled with a T

choronr

That is looking real fine Paul. I would like to suggest that youkeep the camera pointed where it is at; but, zoom backwards until the entire structure is visible. Also, you might consider changing the color of the dust to a gray (with just a tint of redness) - this way, there would be a better visual emphasis on the rock structure. Damn; I know, you just can't please everybody!

old_blaggard

Thanks for the input and comments, everyone. I, too, am still not entirely satisfied with the hard edge, but I think it looks plausible now instead of just wrong ;). I also understand how the stones might be too sharp for some people, but I think I'm going to leave them the way they are. As you've all said - can't make it perfect for everybody :P.

It's true, Martin, that the big technical focuses here were the arch and the dust storm, but I also had to fight a bit with the fake stones to get something that was at least realistic enough to blend with the rest of the scene. Relatedly, perhaps someone can chime in with a word of advice on how to fix my problem: at one point I decided to use some intersect underlying between the larger fake stones and the terrain. However, even after I did that the shape of the smaller fake stones that I added later were always somewhat distorted and didn't have the same shape as the other ones (I disabled smoothing effect in the surface layer, which helped, but didn't completely fix it). Does anybody have ideas about how to get intersect underlying to have minimal impact after the surface layer where it's performed?

Also, I haven't tried scaling my arches up to that level yet, although it certainly should be possible. A couple of things that come to mind:
- The displacement along x in the redirect shader is not applied evenly across the arch: there is a mask that in fact varies it over the course of the base, otherwise it would always become the little paper thing you mention. Try experimenting with slightly different values of Constant scalar 01 and Constant scalar 01_1.
- Increasing the base surface area also helps, so you can certainly expand that.
- If you're getting that folding effect, you can always get rid of it by displacing everything outwards by a few meters.

Finally, if you want to clean up and rearrange nodes to post it for people, that would be great. I was going to just post my project file, but it would be good to have someone with experience in this kind of thing go through and make it more legible.
http://www.terragen.org - A great Terragen resource with models, contests, galleries, and forums.

Tangled-Universe

Quote from: old_blaggard on December 27, 2009, 12:27:55 PM
Thanks for the input and comments, everyone. I, too, am still not entirely satisfied with the hard edge, but I think it looks plausible now instead of just wrong ;). I also understand how the stones might be too sharp for some people, but I think I'm going to leave them the way they are. As you've all said - can't make it perfect for everybody :P.

It's true, Martin, that the big technical focuses here were the arch and the dust storm, but I also had to fight a bit with the fake stones to get something that was at least realistic enough to blend with the rest of the scene. Relatedly, perhaps someone can chime in with a word of advice on how to fix my problem: at one point I decided to use some intersect underlying between the larger fake stones and the terrain. However, even after I did that the shape of the smaller fake stones that I added later were always somewhat distorted and didn't have the same shape as the other ones (I disabled smoothing effect in the surface layer, which helped, but didn't completely fix it). Does anybody have ideas about how to get intersect underlying to have minimal impact after the surface layer where it's performed?

Also, I haven't tried scaling my arches up to that level yet, although it certainly should be possible. A couple of things that come to mind:
- The displacement along x in the redirect shader is not applied evenly across the arch: there is a mask that in fact varies it over the course of the base, otherwise it would always become the little paper thing you mention. Try experimenting with slightly different values of Constant scalar 01 and Constant scalar 01_1.
- Increasing the base surface area also helps, so you can certainly expand that.
- If you're getting that folding effect, you can always get rid of it by displacing everything outwards by a few meters.

Finally, if you want to clean up and rearrange nodes to post it for people, that would be great. I was going to just post my project file, but it would be good to have someone with experience in this kind of thing go through and make it more legible.

Thanks for explaining Paul :)

As I said I've "organized" your network and have renamed the displacement-shaders to name which I "think" they do like controlling width, thickness, height and length.
Further, there are a couple of root-scalars and the like which if you disable sometimes gently influence the shape of the arch, but I have NO idea what they actually do.
Honestly, I have barely any idea how you pulled it off ;D
I just reversed engineered how it worked by changing lots of numbers and things, that's it. So the renaming might not make sense :)

Anyhow, I now can manipulate it to 90% of my likings, besides I still don't get how to avoid the thin paper look.
I will try your suggestion to change those 2 scalars, thanks :)
However, I don't know how the expand the base surface area, which part of the network defines that?

I attached a doodle I made yesterday which also has snow and fake stones. Is this kind of what you're looking for?

Cheers,
Martin

Kadri

Old_blaggard this is a nice and interesting technique  :)

Kadri.

choronr

Just an image of 'Delicate Arch' to view for comparison; I've been here several times over the years. The beautiful rock structure is seen at the 'Arches National Park' in east-central Utah. The hike to the place is uphill and is worth the effort. This place reminds me of the Roadrunner and Coyote cartoons where you must walk along ledges of red sandstone. Worth the visit which I wish all of you could make.

Kadri

When i see such photos and 3d images side by side i see how far we are gone in software and artistic ability   :)

Kadri

old_blaggard

Thanks, Kadri :).

Bob - That was actually one of my original reference pictures (although I decided on a different milieu and rock style in the end ;P)

Martin - first of all, good-looking test! Increasing the base area of the arch couldn't be simpler. Right underneath the Subtract scalar 01 and Subtract scalar 01_1 nodes, simply create two divide shaders. Toss a couple of constant scalars into input 2, and then use larger numbers to get a larger surface area. If you look closely, the first few nodes in the arch are actually the formula for defining the unit circle, and adding the divide scalars turns this into the formula for creating an arbitrary ellipse, so if you want, you can create a more stretched-out arch. The root and square scalars that you're talking about are simply there to provide different interpolations of getting from zero to one. As you said, they influence the shape gently, but it's easier to just experiment with them than to trace out their logical effects (trust me :P). The constants I mentioned before should have slightly more dramatic impact on the scene, especially if you pump in extreme values, but I think that the best results are to be had within the range from zero to two.
http://www.terragen.org - A great Terragen resource with models, contests, galleries, and forums.

Tangled-Universe

Ok, I'm on it! Thanks!

I really had a laugh about this
QuoteIncreasing the base area of the arch couldn't be simpler.
;D lol

btw. I'm really having problems populating this, do you have any ideas?

Kadri

Quote from: old_blaggard on December 27, 2009, 01:09:32 PM
...

Martin - first of all, good-looking test! Increasing the base area of the arch couldn't be simpler. Right underneath the Subtract scalar 01 and Subtract scalar 01_1 nodes, simply create two divide shaders. Toss a couple of constant scalars into input 2, and then use larger numbers to get a larger surface area. If you look closely, the first few nodes in the arch are actually the formula for defining the unit circle, and adding the divide scalars turns this into the formula for creating an arbitrary ellipse, so if you want, you can create a more stretched-out arch. The root and square scalars that you're talking about are simply there to provide different interpolations of getting from zero to one. As you said, they influence the shape gently, but it's easier to just experiment with them than to trace out their logical effects (trust me :P). The constants I mentioned before should have slightly more dramatic impact on the scene, especially if you pump in extreme values, but I think that the best results are to be had within the range from zero to two.

When i read such instructions  i say to me that English is not my mother language . In this way it feels less depressing  to me  ;D

Cheers.
Kadri.

choronr

On the Renderosity site, there are two files available call 'Unique Rocks' (do a search) - I ordered one of them a few years ago. There are about 12 different shapes in the file about which there are a number of arches. They can be opened up in TG2. Worth having a look.

old_blaggard

Quote from: Tangled-Universe on December 27, 2009, 01:13:24 PM
I really had a laugh about this
QuoteIncreasing the base area of the arch couldn't be simpler.
;D lol

btw. I'm really having problems populating this, do you have any ideas?

Heheh, it looks like I've fallen into using one of my professor's favorite sentences :P.

To populate, you can use a bunch of nodes to distort coordinate space on the function level. Or you can use the "Shader array" node that was released twenty-four hours after I'd figured that first one out :P. However, all of the arches will be going in the same direction. I haven't tried this yet, but you should be able to use carefully coordinated perlin noise functions as multipliers of the displacement shader inputs.

Bob - Those look like good packs. I knew from the outset that I could probably find a pretty good arch model out there, but part of the fun of this project was learning how to grow it procedurally using shaders.

I've decided to hunt for a slightly wider composition, (so the word "Finished" in the title is now a lie :P), but I think I am done tweaking shaders.
http://www.terragen.org - A great Terragen resource with models, contests, galleries, and forums.

old_blaggard

If you're curious, here is an early test of populating arches:
http://www.terragen.org - A great Terragen resource with models, contests, galleries, and forums.

Tangled-Universe

Quote from: old_blaggard on December 27, 2009, 01:51:40 PM
If you're curious, here is an early test of populating arches:

Oops, sorry...by populating I meant putting populations on them, like shrubs etc.
My bad (english)!
Cool concept nevertheless!

choronr