Select areas where value is changing rapidly - Printable Version +- Gimp-Forum.net (https://www.gimp-forum.net) +-- Forum: GIMP (https://www.gimp-forum.net/Forum-GIMP) +--- Forum: General questions (https://www.gimp-forum.net/Forum-General-questions) +--- Thread: Select areas where value is changing rapidly (/Thread-Select-areas-where-value-is-changing-rapidly)

Select areas where value is changing rapidly - geobeck - 03-21-2021 I'm trying to create a texture mask for a game map, and need to select the cliffs on my terrain. How can I select the areas where the pixel value is substantially different from adjacent pixels by a certain amount? RE: Select areas where value is changing rapidly - Ofnuts - 03-21-2021 Without a sample, difficult to give a good idea. Possible solution: Duplicate the layer Set the top to "difference" mode Start the "Median blur" filter, when its radius becomes close to the "thickness"  of the cliffs, cliffs will appear over a ver dark background. Make a selection from the adequate R/G/B channel (or create  a new layer and massage it first (desaturation, contrast...)