The title pretty much says it, physics props in my maps never cast accurate shadows. No matter if the lighting is a light, light_spot, or coming from the skybox via light_environment; prop shadows never cast in the same direction as shadows casted by brushes. Nor do they cast in a direction...
This has been an issue with source with many graphics cards since Half-Life 2 was first released. This issue is caused by anti-aliasing causing these artifacts, turning AA off will solve the problem. However, i hate turning AA off, and i assume you do too. To fix this problem within your own...