Solutions/Ideas for Technical Problems

[Sentura]

I don't know if this is applicable to everyone or everything in this section, but I thought it would be a good idea to have a thread about technical stuff and ways to overcome technical problems. We've seen a bit of this from articles posted on the site, but why not put stuff here as a reference bible for everyone? In the same way, people should be free to ask about technical problems and get answers if someone has them.

 

So the other day I was thinking about how to make a proper heightmap for a desert environment. Those heightmaps that already exist for deserts seemed to be a bit too unreal for a realistic landscape. However, yesterday while I was at the beach I realized that the way people make footprints/holes in the sand actually mimics how sand dunes would realistically or artistically appear in the desert (see image), and that using a height map either scaled up or down could make sense as a game environment. At the same time the details of the footprints are relatively low, so it makes sense to use it on a larger scale. Thoughts?

 

 

 

[selmitto]

It does seems a great hack to extract realistic heightmaps for terrain. After all, that's a real photo

How was the result of it applied in an engine? Was the terrain satisfactory?

[mjens]

I'm not sure it the result would be realistic. I think that good reference pics and well sculpted terrain will do the best result. The realistic shape of the desert is rather flat, not so wavy as the footprints but it depends what you need to achieve - maybe you just want to have a "curvy desert" so it's ok then.

There's a method to take out the heightmap of the realistic deserts/mountains from Google Earth via 3DRipper or stuff like that. I guess that's a best idea to get thre shape quickly without any knowledge about creation process of the desert.

[Sentura]

I think the first image you posted is more artistic than realistic for sure. I've been to the Sahara, and it looked more like this:

 

 

Also, erosion only happens on solid structures like e.g. rocks and cliffs. If none such exist structures (as is the case predominantly with the Sahara), the water will just seep into the sand and/or evaporate. The reason other reason for sand deserts never being flat is that there are fairly high winds on flat terrain (see ocean winds), which cause the sand to move into dunes naturally.

 

But yes I guess I should have said a sand desert rather than the rock deserts you see in the americas and stuff.

Edited July 23, 2013 by Sentura

[mjens]

Erosion is a process that shapes terrain. It can be rock, sand, clay...

Anyway, try chekcing Google Earth or look for some heightmaps as a displacement to shape it quickly.

[Sentura]

So I finally got to try it out, and the results have been pretty amazing. Scaling the heightmap from 512x512 to 4 times its size in Cryengine 3 has yielded a very natural desert environment. A few minor adjustments had to be made, the greatest one being that blur was necessary in order to remove noisy peaks, others included rising/lowering terrain in game to create a suitable gameplay location as well as limiting the terrain height to something more earthy (in this case.I used 256 units).

 

This is the heightmap I used (same as previous imaged I posted but cropped. raw converted to png for upload):

 

 

Result (taken some 100m above human height)

 

 

There are only two problems in this approach:

 

1) The beach sand only has wavy lines one way because of the shoreline washing up. However, this can be remedied by superimposing the same image (or another beach image) turned at 90 degrees for more grid like waviness.

 

2) Given the flatness of the terrain, the desert will need to be bigger than just slightly over 4 Kilometers (4096x4096). For a desert terrain to make sense, one would most likely need double that size to create the illusion of endlessness. However, this is still doable, albeit more resource consuming.

 

Also, seir: I tried with google earth, and the resolution is nowhere near good enough to use. I also tried with smoothening this, but the result was a desert that came off as bulky and rigid rather than flowing like sand. Also, erosion on sand doesn't exist (http://en.wikipedia.org/wiki/Erosion), though you could probably argue that wind on sand has somewhat the same effect. It does mean that sand deserts come off as more wavy rather than just flat, however.

Edited July 28, 2013 by Sentura

[e-freak]

well one problem your approach is that you take the colored image and turning it into a height map. shadows become valleys instead of hillsides - the result is still interesting to look at but to reproduce the original image's shapes you would probably want to use a different conversion method. (check if next pixel to the right is brighter or darker and increase or decrease brightness value based on it - kind of what a normalmap to heightmap converter does).

[2d-chris]

http://www.world-machine.com/about.php

+

http://www.o-openuniverse.org/story/dune-generation-world-machine

might be worth a shot