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View Full Version : How to add clouds or fog to an existing map in GIMP?



Absinth
02-22-2009, 08:59 AM
Hello cartogaphers,
I'm in the process of creating a map for a seaside adventure's location and I'd like to add a layer of thin fog on top of the map. The fog should be transparent and shouldn't hide the features of the map, only obscure them in some places. It's really just to set the mood for the creepy adventure that'll take place there.
How would you manage this?

Redrobes
02-22-2009, 09:29 AM
In a VTT we just add a token which is a semi transparent PNG with a tint. Like this...

In PS etc just add a layer, fill it with blue, white or orange and whack down the opacity.

torstan
02-22-2009, 10:59 AM
In Gimp create a new layer above the map. Take a large fuzzy brush (size of 50 to 100 or more) and a very light blue. Paint in the regions you want to be misty. Don't be afraid to go too heavy, you can always lower the opacity of the layer to get back the map.

RobA
02-22-2009, 01:41 PM
in Gimp 2.6 there is a filter Filter>Render>Clouds>Fog that produces a semitransparent random cloud layer.

-Rob A>

sambrookjm
02-22-2009, 07:00 PM
in Gimp 2.6 there is a filter Filter>Render>Clouds>Fog that produces a semitransparent random cloud layer.

Are you sure that's not a homemade script that you've got installed? I've got GIMP 2.6.5, and I don't have the Fog option in the Clouds submenu. I've got Difference Clouds, Plasma, and Solid Noise there, but no fog.

Granted, it would be easy enough to make a new layer on top of your map, render some random noise, and reduce the opacity somewhat (depending on how thick you wanted the fog). Maybe change the layer mode to overlay as well?

jfrazierjr
02-22-2009, 07:40 PM
http://gimp.sourcearchive.com/documentation/2.6.0/foggify_8py-source.html

That is the source. Put that into your plug-in's directory in a file with a .py extension. you will of course need to have Python support installed for GIMP prior to it working....

jfrazierjr
02-22-2009, 07:42 PM
Granted, it would be easy enough to make a new layer on top of your map, render some random noise, and reduce the opacity somewhat (depending on how thick you wanted the fog). Maybe change the layer mode to overlay as well?

Well... one good thing about the foggify filter is that you don't have to Delete stuff. Normally. noise is either black or white and covers every single pixel in your image in some shade. The foggify filter also addes in alpha to this, so you have patches of (mostly) white colored fog and the rest is alpha instead of black.

RobA
02-22-2009, 08:27 PM
Are you sure that's not a homemade script that you've got installed? I've got GIMP 2.6.5, and I don't have the Fog option in the Clouds submenu. I've got Difference Clouds, Plasma, and Solid Noise there, but no fog.

jfj was right - it is a python script and is installed in the base gimp install.....IF you have python support ;)

-Rob A>

sambrookjm
02-22-2009, 08:48 PM
Looks like there was something I forgot to install after I had to wipe my laptop's hard drive after all... :)

I'll give that a shot.