I'm a beginner in Blender - i have a problem with mysterious shades in flat surface. Model comes from SketchUp (exported to OBJ / imported to Blender).
Model is composed of blocks, shades are near block's edges (but only on some of them). My idea was Sketchup model have some smooth edges, but it haven't...
Any idea what is the problem??
Thank you very much in advance!
EDIT full resolution preview: http://lukex.name/temp/preview.png