[Award Winner] Fun with Wilbur, Volume 1

[su_liam]

That's looking like a place. Real nice.

[su_liam]

How would that work just adding a little high-frequency low amplitude perlin instead of uncorrelated noise to break up the flat basins? Would that be worthwhile?

[NeonKnight]

What I would REALLY like to see is a good:

FRACTAL TERRAINS to WILBUR and BACK tutorial.

I've played with the Erosion in Wilbur, and I don't know, it almost seems like it does more in Wilbur than it does in FT.

[waldronate]

How would that work just adding a little high-frequency low amplitude perlin instead of uncorrelated noise to break up the flat basins? Would that be worthwhile?

It should work just as well with one of the other noises as with the uncorrelated noise. The problem with relatively large basins will remain unless you use a noise of such high frequency that it's pretty much uncorrelated.

The primary reason to use the uncorrelated noise is that the basins are 1 pixel wide and so will not result in flat areas with straight erosion artifacts. The negative part of using the very high frequency noise is that the river tend to have a very high curvature, which sets a lower limit on plausible size of the map.

[loogie]

nice post.... i'm playing around with it and working on my DEM i made for editing in arcgis... (bryce and my past efforts have been lacking, especially in erosion)

[su_liam]

I see what you're saying there Waldron. Strangely, while I'm pretty well grounded in the math, I have a lot of trouble visualizing the results.

I'm curious is there any way to get a mask of basin areas from the Fill Basins filter? Failing that, and perhaps more generally useful, could you have a 'Select Flat' option. That is a selector that scans a window around each pixel(say 3x3) and selects that pixel if and only if all points within that window are within a given variation(epsilon?) of each other. Then you could noise up the supernaturally flat basins while leaving the yummy ridginess of the mountains pristine.

I wasn't initially sold on the terracing produced by the Remap Altitudes, but I like how the Precipiton mostly beats that down. It also erases a lot of the streambeds. Another thin Incise Flow at that point might be nice. (?)

Anyway this deserves a rep.

[RobA]

The magic wand can be used for selecting a basin. The tolerance is specified in actual height units (I think).

Here is the same example (except I applied an exponent to the height-field at one point) with the basins selected with the magic wand before applying the noise...


-Rob A>

[su_liam]

That sure is purdy RobA. It almost looks glacial. Somebody should point Monks at that. I'm not sure how much of that is the noise masking and how much is the exponent.

It looks like I'll have to fire up Wilbur after work tonight. I'm thinking about adding another Incise flow after the Precipiton stage. Hmm, I think I'd use an intermediate blend(maybe 1.0), a smaller amount(again, perhaps 1.0), the Flow Exponent and Effect Blend are a mystery to me, so that would need fiddling.

[su_liam]

It turns out my old version of Wilbur(something like 1.54, I think)had some serious problems with Incise Flow. After spending most of the evening d/ling the new Wilbur version(and the entire .Net framework, apparently), I found out the Cow Machine with it's fully paid off copy of Win98 was unable to run that new version. Maybe I'd be better off getting an emulator for my mac. It couldn't be any slower than the 20th Century POS at work.

I would be interested in an explanation of some of the controls in this program, particularly Flow Exponent and Effect Blend in Incise Flow. Also is, H in your heightfield generation equivalent to Persistence? In that case, an H of 1 would mean each octave is of constant amplitude but 1.9 times the frequency of the previous(for a Lacunarity of 1.9, anyway).

[waldronate]

I see what you're saying there Waldron. Strangely, while I'm pretty well grounded in the math, I have a lot of trouble visualizing the results.

I'm curious is there any way to get a mask of basin areas from the Fill Basins filter? Failing that, and perhaps more generally useful, could you have a 'Select Flat' option. That is a selector that scans a window around each pixel(say 3x3) and selects that pixel if and only if all points within that window are within a given variation(epsilon?) of each other. Then you could noise up the supernaturally flat basins while leaving the yummy ridginess of the mountains pristine.

I wasn't initially sold on the terracing produced by the Remap Altitudes, but I like how the Precipiton mostly beats that down. It also erases a lot of the streambeds. Another thin Incise Flow at that point might be nice. (?)

Anyway this deserves a rep.

One way to select flat items is to use a shader trick. In the Wilbur shader, set the land color list to one white color and the Intensity to be 90 degrees elevation with 1000 vertical exaggeration. Then all flat (or nearly flat) areas will be white and all non-flat areas will be black. Texture>>Transfer>>Texture to Selection will make the selection from the displayed image so basins will be selected and non-basins won't. I agree, though, that it would be nicer to have an option such as you suggest that would perform this trick in one step.