This is really detailed for a concept piece, and it's not bad either! It reminds me a little of a house I saw in California, it had round walls of glass like this room and was built out of a rock face. I'd love to see a more detailed version if possible.
how long does this kind of concept sketch take you? It is wonderfully detailed, despite the vague strokes...the smaller ones fit into a beautiful larger picture. I'd love to paint/draw like this. Lovely colors too