I got some weird shadows and lightning forming on my models. its very low poly and i don’t know whats going on
looks like double geometry. Goto edit mode, merge by distance. Or you could use 3dprint toolbox addon that comes with blender. it shows you problems.
İf you mean that line straches, it because duplicated faces, there is 2 faces at same location, if you have 2 same model, delete one of them. İf you have only one object, you can use select all vertex and press m to merge by distance