This shading applies to the entire building. If the sun is shaded, none of the exterior components receive direct sunlight. This means that distant obstacles are correctly detected and closer obstacles can be approached.
The "Add Object" button enters a shading that is caused by an object with the entered distance, height, width and azimuth direction (south deviation) into the raster image. The azimuth can be entered in degrees of -180° (north) and 180° (north).