http://www.fsdeveloper.com/forum/threads/what-exactly-is-a-blendmask.441166/
According to what I understand, a blendmask is a area that the underneath scenery shows trough the scenery you are making. I also have a few questions:
If a blendmask is drawn with a brush with
low hardness in the image editing tool, will your scenery "
fade" into the surrounding scenery?
And will a blendmask work if it is drawn with the "
pen" tool in a image editing program?
Thanks in advance.
Hi Caleb:
In the graphics applications that I am familiar with, a single color is assigned by the end user to the
Pen,
Pencil, or
Line tool, and that color can be selected by the end user using the
Eye-Dropper tool.
Thus, you can assign a particular color from the 256 steps of "color" within the gray-scale palette of a 8-Bit TIFF Blend Mask image to use with the "
Pen" tool in
8-Bit gray-scale "
Blend Mask".
FYI: You may wish to first edit a
copy of the 24-Bit color photo-real aerial imagery to create a "Water Mask" in
ex:
GIMP
1.) Use the
Magic Wand tool to select 'water area' colors
2.) 'Flood-Fill' that initial "mask" with pure Black (RGB 0,0,0) over
Water areas within the aerial imagery
3.) Select and '
Invert' that "mask"
4.) 'Flood-Fill' that '
Inverted' "mask" with pure White (RGB 255,255,255) over
Land areas within the aerial imagery
5.) Save a copy of
only that "Land-Water Mask" layer as a
24-Bit color photo-real aerial imagery file in GIMP native *.XCF format.
https://docs.gimp.org/en/gimp-images-out.html
6.) Activate GIMP's 'Indexed Colors' < Black + White > mode
NOTE: This will convert the image into a
1-Bit Black + White "Water" Mask (and is
very much smaller than a 24-bit color image)
https://docs.gimp.org/en/gimp-tutorial-quickie-change-mode.html
7.) Save a copy of
only that "Land-Water Mask" layer as a
1-Bit Black + White "
Water Mask" in
TIFF (
*.TIF) format.
https://docs.gimp.org/en/gimp-images-out.html
[
EDITED]
NOTE: Final output source file format for TIFF Masks must actually be 8-Bit gray-scale; see:
http://www.fsdeveloper.com/forum/th...-scenery-achievable.440912/page-4#post-789447
[
END_EDIT]
8.) Close that
copy of the 24-Bit color photo-real aerial imagery used to create a "Water Mask"
Next:
1.) Open the above "Land-Water Mask" layer you saved as a
24-Bit color photo-real aerial imagery file in GIMP native
*.XCF format
2.) Merge all layers into a single layer via "
Merge Visible Layers"
https://docs.gimp.org/en/gimp-image-merge-layers.html
3.) Use the
Eraser tool with a soft-edge brush and a "
low"
ex: 25 to 50 %
'hardness' (aka "50 to 75 % transparency") to create a gray-scale gradient in the (originally pure Black (RGB 0,0,0) water mask along shorelines to allow the aerial imagery to 'fade' from Land areas into Water areas.
NOTE: Use the same editing procedure above in order to allow the aerial imagery to "
fade" into the surrounding (underlying) Water Class or Land Class scenery textures.
FYI:
* Where gray-scale values are greater (aka "
lighter") than mid-gray-scale (RGB 127,127,127) photo-real "transparency"
decreases
...thus
decreasing ones ability to see any underlying Water class textures
or Land Class textures with any mapped Autogen
*Where gray-scale values are less than (aka "
darker") than mid-gray-scale (RGB 127,127,127) photo-real "transparency"
increases
...thus
increasing ones ability to see any underlying Water class textures
or Land Class textures with any mapped Autogen
* Where a pure Black (RGB 0,0,0) gray-scale value is used,
only the FS default Water Class texture can be seen.
4.) When finished editing the intended "Blend Mask", activate GIMP's 'Grayscale' mode
NOTE: This converts the image into a
8-Bit gray-scale to be used for a Blend Mask (which is much smaller than a 24-bit color image)
https://docs.gimp.org/2.9/en/gimp-image-convert-grayscale.html
5.) Save a copy of that edited "Land-Water Mask" layer as a
8-Bit gray-scale "
Blend Mask" image in
TIFF (
*.TIF) format.
CAVEAT: Be aware of the various file format options to be used- and avoided- when saving TIFF and other files in GIMP:
http://www.fsdeveloper.com/forum/th...-scenery-achievable.440912/page-4#post-781748
NOTE: Be especially careful to
never save a file from GIMP with "
ICC sRGB Color Space Profile Embedded" for use with SDK Resample.
Features and options may vary between different versions of GIMP.
Hope this helps !
GaryGB
