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View Full Version : An experiment with Wilbur and Bryce



su_liam
09-21-2009, 05:30 PM
This is a little experiment I did with building up a terrain. Basically, I started in Wilbur with the default image size(192x192, I think). I used the tesselation tool with a bit of fractal noise to create the initial slope and sketch in the ridgeline. My attempt to create a piedmont and escarpment structure was not altogether successful, but I know what my error was.

I then used fill-basin to correct the drainage, added a bit of noise to roughen up the flat areas that resulted, then refilled. Next, I looked at the river finding texture to make sure that my streams are decently meandery rather than diving straight down. I repeated the noise-fill-river routine till my river structure looked good to me, then I did an incise flow with a high exponent(2/3 to start with) and a fairly high blur. Here I pretty much followed Waldronate's noise-fill-erode tutorial, decreasing the blur and exponent with each step. Before each incise flow step, I made sure to look at the river flows. At this low res river flow is decently quick and it's miserable to fix a big ugly straight segment after burning it in with incise flow. If I see any ugly spots in the river network, I add noise, fill-basins and look again. Rinse and repeat as necessary. I think somewhere in here I played with precipiton erosion, but hey... My memory is not perfect.

At this point I used Simple Resample to increase the size of my image to about 1200x1200. Now things slow down a bit, but if I have a good foundation I shouldn't need more than a few iterations to add a bit of detail. Basically, I just repeated what I did on the smaller image, but less so.

Another resample to 2048. Adding detail here was a bit slow, but it's still a good idea to keep looking at river flow so that things keep looking good.

I created a straight blend of altitude and slope textures using an atlas-type gradient I found in the Fractal terrains folder. I built a terrain in Bryce using the 16-bit png I exported from Wilbur and textured it with the surface texture just mentioned. The result was the cheerfully-colored image on the right. There was a slight conflict between the lighting direction in the texture and in Bryce. This isn't a bad way to bring out some detail if not too extreme and used in moderation.

I decided the detail was a bit weak so I resampled to 4k(4096x4096). Adding detail and erosion at this point was glacial, but still worthwhile(I wanna MacPro!!!), so I only did one iteration.

I used photoshop to create a new texture for Bryce as well as alpha channels to add specularity and reflection to the rivers, some bump height to forest areas, and a higher diffusion value to the icy mountain tops as they tended to go seriously gray. I spent as much time on the texturing as I did on the built-up terrain for a less satisfactory effect. I did like the forest texture, though.

The texture and HF resolution was 4k for the image on the left.

I think I'll be using this technique in the future. Starting with a low res image allowed me to get an attractively-eroded terrain quickly, with only a little bit of erosion added at higher resolutions where the tools get boggy. This was a good compromise between quality and time.

p.s. The best way I've found to iteratively add noise is to add about 5% percentage noise and an absolute magnitude noise of 3-5. The iteration after my first basin fill was more extreme(15%, 12-25). Also, in the left image there is no river coloring, the rivers in the image are altogether the result of reflection effects in the renderer. I'm not altogether convinced that's a good thing. I might multiply in some ps Add Noise on top of the river map I used as an alpha channel for reflection. Hmmm:?:

su_liam
09-21-2009, 07:27 PM
Here's another shot up the slope. Up "close" the rivers look... interesting.

Redrobes
09-21-2009, 07:33 PM
Cool stuff su-liam. Generally when I am creating a terrain for an arbitrary map I start with something like a 256x256 and up the res progressively whilst calculating flow and erosion. Its much easier than trying to fix it at high res.

The problem comes when you want to make a map that looks like what someone else has drawn. You can lower that somewhat and get it right then go back high res again but it less easy than if you dont care what it comes out like as long as it looks good.

Good stuff tho.

EDIT -- looking at new photo you can see what I was saying about mountains where you need to map the temperature as the ice falls down the slope. It all cuts off in a line in this photo.

su_liam
09-21-2009, 08:27 PM
I'm thinking about using the relative elevation value to alleviate that. Select by altitude to get the high points, then modify the selection to a distance selection. Create a selection of the low points on the relative elevation grid also modifying this to a distance selection.

Add the value of the first selection to the second selection multiplied by a weighting constant. If the threshold and weighting constants are well selected, then I think you'll wind up with high areas selected and channeled areas surrounded by higher ridges selected to a lower altitude. At lower elevations, snow will tend to cling to protected basins.

Edit: Looking back at it and earlier versions, it might also help to take slope into account, although slope and relative elevation have to be related.

Edit1: Didn't work...

Alfar
09-22-2009, 05:04 AM
That does look quite nice. And a very detailed explanation of the process. Thanks!

Redrobes
09-22-2009, 06:32 PM
Hey Su-Liam, Remind me again, what OS do you use and how much RAM you got ? Do you run Windows (x64 or x86) or just Mac only.

su_liam
09-22-2009, 07:05 PM
Cool stuff su-liam. Generally when I am creating a terrain for an arbitrary map I start with something like a 256x256 and up the res progressively whilst calculating flow and erosion. Its much easier than trying to fix it at high res.

The problem comes when you want to make a map that looks like what someone else has drawn. You can lower that somewhat and get it right then go back high res again but it less easy than if you dont care what it comes out like as long as it looks good.


Depends on how precisely they've drawn it, too.


EDIT -- looking at new photo you can see what I was saying about mountains where you need to map the temperature as the ice falls down the slope. It all cuts off in a line in this photo.

I still haven't fixed that. To give Mr. Slayton his due, while Wilbur is slow on a 4k square, so is Photoshop!!


That does look quite nice. And a very detailed explanation of the process. Thanks!

Thank you. I'm glad you like it, since I'm really enjoying your program. :)

su_liam
09-22-2009, 07:29 PM
Hey Su-Liam, Remind me again, what OS do you use and how much RAM you got ? Do you run Windows (x64 or x86) or just Mac only.

My copy of photoshop is on my mac volume, but I have windows xp(32-bit), which I run in Bootcamp. I have 2 gigs of RAM, and about 1.5 terrs of HD space and a 2.1GHz Core 2 Duo. Basically the iMac of laptops.

su_liam
09-28-2009, 05:05 PM
In the foreground of the perspective image(SW corner of the map), we see the Ehrlech Fens, home of the dreaded Muck Ogres. In the background we see the Grimtooth Mountains, ruled by the dragon Grimtooth from his lair on top of the great Mount Eisenzahn. The Trollhome Piedmont, at the foot of the mighty Grimtooths, takes its name from the Bloodfoot clan of Hill Trolls, tributary to Grimtooth himself.

This is my continuing experiment with texturing and light erosion thanks to Redrobes. At present, this terrain is only in 1024sq., but is already pretty nice, I think. Now to separate out some more channels, and see how this looks with variable specularity and such!

Alfar
09-29-2009, 03:14 AM
That is tres cool! Love the jagged peaks.

su_liam
09-29-2009, 03:19 AM
I particularly like the gingko-vein look of the streams in the flat lowlands. A saturated stream pattern; I suspect it of being swampland.

Steel General
09-29-2009, 07:27 AM
This is looking really cool - looking forward to seeing more.

Ruedy
09-29-2009, 02:05 PM
Wow, one of the best Wilbur-Result I ever have seen.