Hi Olly - Thanks for the hints! I was able to get several sketches combined in GIMP. Looking at the result, it is very obvious that much more work is required in the cave. There is a huge hole in the middle which has no detail at all. There are missing walls in several places. My plan now is to print the combined sketches on a piece of paper. The next survey trip I will draw more on it. That will then become the background in Therion. The room is not so big as to be a problem in Therion. It would probably fit in a bounding box 25 meters on a side. That is a large scrap, but I think it should be no problem to draw. The two entrances to the room are well-defined, so adding it to the map will be fairly easy. ======== Bill Gee On Monday, June 21, 2021 6:24:28 PM CDT Olly Betts wrote:
On Mon, Jun 21, 2021 at 04:31:45PM -0500, Bill Gee wrote:
Now I need to figure out how to set transparency on each layer.
Bring up the Gimp "Layers" dialog (shortcut key is Ctrl+L) and you can click on each layer and drag the "Opacity" slider to make them partly transparent. Or you can change the mode on each layer to "Darken only" and the result will be the darkest part of any layer, which is probably what you're after (assuming your sketches are dark lines on a white background).
I wonder if Bruce's faint memory about setting transparency with an external editor worked because of using PNG format? My own faint memory is that xTherion uses different libraries to handle png and jpg files. Handling of transparency is probably a feature of the image library rather than xTherion.
I don't think the standard JPEG format supports transparency.
Cheers, Olly