Creating RAW Terrains with Photoshop, or similar

[Cam Chattoway]

Hello... I've been tinkering with photoshop creating raw terrains with mixed results.  So far I've been able to modify some purchased terrains, but I am mainly working with either shapes (aircraft, cars, spacecraft) in an overhead orthographic.. I fill in the appropriate height, multiplier, water levels, and get a recognizable shape, but along all the edges where it joins is spiked looking... for example where an airplane wing meets the fuselage will have big spikes (2-4 m tall) when terrain renders.

I'm pretty new to this but find it quite fascinating.  I have looked at Terragen 1,2, but they seem like massive overkill for 256msq. Bryce is really promising, but again, tho easier to control than terragen (IMO - no offense), it is also a bit of overkill. I am here for help tho - lol... go for Bryce?  Terragen(s)?  Balliwick?  I mean, I really want to make creative progress without having to fine tune the terrains in world as much as I've had to exclusively using photoshop.

[Ceera Murakami]

There's no reason you can't get flawlessly smooth raw file results out of Photoshop.

If you're getting spikes and the like, it is because your image has 'noise' in it, most likely caused by anti-aliased edges when you cut and pasted your shapes. Make sure you use no anti-aliasing at all with any of your selection tools.

You may also want to try a light monochrome gaussian blur to smooth things.

Also, you have to bear in mind that a raw file is a very coarse terrain mesh to begin with. You only have 256 x 256 pixels to work with, so that means that you're dealing with a 1-meter grid of points in the X and Y directions, and a 0-255 greyscale value for height. (0 to 255 Meters altitude in 1 meter incremental steps, before dealing with the height multiplier layer.)

What I do to make smoother terains is i put in a height multiplier value that results in cutting the heightfield values in half. So instead of a vertical range of 0-255, I have a range of 0-127, BUT, I have a half-meter incremental step vertically, instead of a full meter. This allows the transitions form piont to point to be much smoother.

 

[Cam Chattoway]

Thanks for the reply.... so with regards to any spikes that do appear, (gaussian blur helped some... just mounds instead of spikes).   The heightfield (green) would be divisible from 256 down to make lower terrains if I understand right.... so 128 would be 1:1, or 64 would be 1:2.. etc... ?  Sorry - these should probably be based on 0 rather than 1 as the starting point...

Is that roughly what you're describing?

[Ceera Murakami]

Yes. Look here for a detailed discussion:

http://wiki.secondlife.com/wiki/Tips_for_Creating_Heightfields_and_Details_on_Terrain_RAW_Files

Channel 2 set to a greyscale value of 128 will have zero net effect on your channel 1 heightmap , so greyscale 50 in the height map (channel 1), for example, is a height of 50 M (or 30 M above the default 20 M water table).

Channel 2 set to a greyscale value of 64 will cut the effective heights in your channel 1 heightmap in half, so greyscale 50 in the height map (channel 1), for example, is a height of 25 M (or 5 M above the default 20 M water table). So using a height multiplier value of greyscale 64 makes your heightmap translate to a 0 to 127 range.