I recently started with blender and quickly ran into a particular issue that I am hoping someone may have experience with and hopefully some insight on how to solve it.
The model I am currently working on was created in sections, for instance the limbs were created separately from the body, and now I am in the process of connecting the limbs to the body. I made sure that the two ends had the same number of vertices before trying to connect them, The legs connected smoothly, but for some reason the arms did not. I tried deleting the discoloured faces in the arms then reconnecting them and that did not work. I even used the remove doubles function just in case there were overlapping vertices, and I went into wire-frame mode to make sure there were no faces in the model that might be connected perpendicularly in the problem area. I have screenshots with the problem areas circled to give a visual.
See the different shades of grey on your model?
The darker shade of some polygons indicates that you spoiled the face normals while modeling that object: Some are pointing inward (dark grey), some are pointing outward (light grey). That shading artefacts you see is Blender trying to cope with a mesh that’s literally turning inside out and back again.
Tab into Edit mode, hit A to select all, optional: W > Remove Doubles and finally Ctrl-N to recalculate the normals.
