I've done it, but it's been a few years. I didn't use a pre-existing height map, though, I created my own - I needed a simple smooth amphitheater, and I remember using the gradient tool to get that. Here are my notes, and I regret to say I have no idea where I got the information. Someone other than me should be getting credit for at least some of this:
Starting from scratch in Photoshop: for a 256x256 sim, make a 256x256 RGB 16bit file. Then to go your channels tab, and create 10 alpha channels – you won't use them, but OpenSim won't accept the terrain files without them.
RAW files are flat, one layer, and 13 channels; RGB plus 10 alpha channels.
The red channel holds the terrain height information, the green channel determines resolution of the red channel, and the blue channel is water height, which you can also edit inworld.
Blue channel: if you want the water to be 20 meters, the default, then paint the entire channel in RGB 20,20,20 grey.
Green channel: It's a good idea to start with a RGB 32x32x32 in the entire channel. That multiplies your resolution in the red channel by 4.
Channel 2 (green) is a grayscale map that is used as a multiplier to scale the data in channel 1, resulting in the final height of each point on the map. The formula used to combine the 2 channels is: original height (channel 1) * multiplier (channel 2) / 128. A few examples will help to illustrate their interaction.
32 -- Divides pixel values by 4. The resultant elevations will be 32 / 128 = 1/4 of the original
64 -- Divides pixel values by 2. The resultant elevations will be 64 / 128 = 1/2 of the original
128 -- No effect : 128 /128 = 1 times the original.
255 -- Multiplies pixel values by 2. The resultant elevations will be twice that of the original : 255 /128 is about 2.
Red channel: if the green channel is 32, and you want a flat sim with the terrain at 22 meters, for example, then you paint the red channel with RGB 88,88,88. Which divided by 4 = 22 meters.
When you're done with your terrain painting, use a gaussian blur to eliminate noise and pixellation – each pixel affects a visible amount of terrain, and you'll see spikes if your channels aren't clean.
Be sure to name your files without spaces.
256 x 256 pixels
13 channels
Interleaved
8 bit depth
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Michael Timeless wrote: ↑Tue Oct 02, 2018 3:54 am
My primary purpose in Kitely and other grids is to create recreations of areas that I've visited and love in RL. Unfortunately, the terrain tools don't always work so well when trying to recreate actual areas. Recently, I came across a website that takes actual areas and creates terrain heightmaps that are identical to the USGS mapping data. I was ecstatic until I saw that what they created was PNG Heightmaps. I have tried to convert these to .RAW files useable in Kitely using both GIMP and Photoshop CC 2018, Version 19.1.5, without success.
Several searches on the Internet have shown that this conversion is possible but none of the links on those sites work and on the few that did work, the process didn't work when uploaded to my sandbox. Has anyone had any luck in creating .RAWs from PNG Height Maps? I am eager to learn because this program of creating realistic terrain maps is so promising for all worlds.
Thanks for any help or advice anyone has.
Mike