Since Render Monkey has been discontinued (perhaps due to the complexity of today's shading languages), there are few successors that can match its functionality. Is there any useful tool for material editing aimed at developers and artists alike, but concentrated (or with substantial support for) on embedded GLSL shaders?
Render Monkey itself wasn't that flexible (I'm not aware if it allowed the usage of several textures, each with its own set of texture coordinates - plus, it didn't seem to be that intuitive either). Apart from complete engines, is there such a stand-alone tool that can be used together with a stand-alone engine (able to interface with a custom application)?