I made a footbridge in Blender and imported it to Unity. I got it imported and got it's textures applied correctly (UV mapped in Blender). It looks OK except the planks and handrails are supposed to be flat and they all are slightly shaded so they look like puffy wooden pillows, not flat planks. I noticed that if I take off all the texturing, the base material also makes the planks and posts look rounded instead of flat or square. I have the shader set at diffuse with a white main color. How can I make my planks look flat instead of rounded? Thanks.
You can try setting the normals to calculate instead of import in Unity, and reduce the smoothing angle. That doesn't work for every object though. The "correct" way is to use an edge split modifier for the object in Blender, set to "From Marked As Sharp" only (not "From Edge Angle"). This modifier just needs to be present on the object; don't click "Apply". Then select all the edges that should be sharp and select "Mark Sharp" in the edge specials menu. Another method is to use the set smooth/set solid buttons for selected faces and export as .obj, since the smooth/solid faces are baked properly into the .obj file. However that's kind of a pain since you have to deal with exporting .obj files instead of just saving the .blend file.