Cant smooth object nicely

Help, I am sure this has been covered somewhere- I imported a DFX wire frame to Blender but trying to get some parts of the model to smooth nicely isnt working - tried sub dividing and the smooth option but its still rubbish. If I start with a completely new tube it does so what is the issue? Thanks for any assistance.



somewhere in the red square area should be “clear custom normals” or similar. usually it happens with imported meshes. if it’s not cleared, do it and try smoothing again…