I loaded Blender and pushed space>add>mesh>tube, i made it tall as i needed in edit mode, then selected the upper vertex>extrude>clic>scale to make the thickness, then extrude until down, and connected all the vertex to make the faces, obtaining a tube. Then when i tried to render I get this. Why?? I recalculated the normals and everything but nothing works.
Also, why sometimes, making similar objects with same procedure, one is rendered good and one is like that?
Thank you
PS: This happens only when I use “set smooth”, if i put “set solid” it renders good but, of course, with faces, which I don’t want.
This is not a bug. It happened because when you turn on ‘set smooth’, Blender tries to smooth EVERYTHING, including the 90 degree edge of your tube. By default, when you turn on ‘auto smooth’ it makes the ‘set smooth’ function ignore all angles greater than 30 degrees.