Make the Wash tool more accurate to Washes in real life miniature painting.#636

Currently when using the Wash tool it applies the shading as both recess shading (What a wash does in real life) and as a Shadow shading (darkening the under sides of parts etc.).

Coming from a Mini painting backhround the Wash tool didn’t work quite how I expected as it also baked in shadows as if from a light source as well as shading the recesses. Ideally the recess shading and light source shadows should be seperate tools for finer control without having to manually shade parts using the airbrush tool.

See attached sample images for an example: The top has it’s recesses nicely shaded while the underside is just completely blocked out with the shading.