August 2015 Entry: From a collage of bits of DEM's to a modern looking Contour-Map

[Pixie]

So, the name should really say it all...

I'm in a rush here to get this posted, will edit later

### Winner ###

tutorial_COLLAGE_to_CONTOUR.pdf

[Akubra]

Pixie, can you read people's minds? This was EXACTLY what I was trying to do all afternoon. The only thing I didn't think of was starting from real DEM pictures. I went for another technique of drawing bits and pieces of the map myself and let Wilbur adjust it with noise and blur and such things, but it didn't lead me anywhere. Man it's really eerie, I even used an adaptable greyscale division like in your step 5. Thanks a lot for this!

Cheers - Akubra

PS. I can't give you some rep for this yet, but you'll get it as soon as I can!

[Redrobes]

Cool - we use something like this to make the mountainous regions in MeDem. In our process we downloaded a lot of mountainous dems from SRTM and similar license free sources then we made square tiles of them. Then we made the tiles seamless and generated a complete mountainous DEM the same size as ME. Then we use a masking system to mask in where we need mountains.

Originally we modelled them by hand but its real hard to model mountains. They never seem to look right and in Outerra where you can zoom right up to them and fly around them they just dont look right. So by using real ones we side stepped a big issue.

You can see some of the results here:
http://me-dem.me.uk/galleries/Development2/gallery.htm

If I recall we had some issues with the blending of the heights between the mountain DEMs and our existing height map and we had to write some extra code in the blender to ensure that the mountain heights were added to a base height so that the troughs between mountains maintained the right water courses else they would go below the base DEM height. Cant quite recall what we did as it was about 3 years ago now.

Also worth noting is that there was some kind of plug in for WorldMachine which did some nifty real DEM painting from sources. Cant quite recall who wrote that but it was that Microsoft researcher. Oh yeah here it is - Howard Zhou !

http://www.terrainsynthesis.org/worldMachine/index.htm

Its a bit of an old idea but you have a nice instructional tutorial for it - well done.

[Pixie]

Thank you both for the warm comments.

I didn't think I was putting forth a tutorial that would be ground breaking. If anything is new (to my knowledge - very limited knowledge), its' the mix of Levels Adjustment Layers on Photoshop with subtle erosion procedures on Wilbur.

I tend to prefer manual processes when it comes to making mountains/topography because you can model something that is scientifically more sound/believable (particularily from the tectonics perspective).

[waldronate]

One blending trick in Wilbur is to load the DEM with sharp transitions and then:

1) Texture>>Gray Maps>>Relative Elevation. This process will select sharp changes in altitude.
2) Texture>>Transfer>>Texture to Selection will transfer that image that marks sharp transitions over to the selection.
3) Select>>Feather with a value around 1 will smooth out the transitions a wee bit.
4) Filter>>Blur>>Gaussian Blur with a value around 2 will smooth out the edges.
5) repeat as needed

This technique is basically a poor-man's edge blur (only edges are blurred). Inverting the selection between step 2 and step 3 will blur everything but edges. It goes through the selection, so there is a bit of clipping because the selection has only 256 possible values, but it's usually not too bad, especially after a few iterations.

[Bogie]

Cool stuff, welcome to the challenge Pixie, glad I'm no longer the only last minute sign-up.