Semi-Cylinder won't smooth and shows faces

Support Basics & Interface
1

Okay… I’ve got a tube that has thickness to its walls and its been distorted on one side… setsmooth doesn’t help me a whole lot, and subsurf makes it all spikey… even when full OSA is on it doesn’t help… the individual faces continue to show, and I don’t know how to remap the faces, or how long that might take.

Alright… I’ll stop trying to describe it and just give you all a link to it.

http://www.geocities.com/cronocat0/spikey.zip

Object in question is object:“mainbarrel”

2

Hi Cronocat,

Well, looking at your tube I can only say that you have to work on your mesh modelling techniques. I guess you modelled it with boolean subtract? I see many long triangular face which almost always give bad result when rendering. I also see some overlapping faces, not sure how you created them.

Ok, let me help you build an easy basic smooth tube.

  1. in topview, create a circle (space->add->mesh->circle->ok)
  2. Extrude the circle but don’t move the points (press E->Region->RMB)
    You have now create an extra circle of points on top of the first one.
  3. Scale the new circle (press S and move mouse to scale)
  4. Go to frontview and select all the vertices (press A twice)
  5. Extrude Region to create a basic tube
  6. Select all vertices and press Ctr-A, to Recalculate Normals Outside. (To see the normals on your model press F9 in edit mode and click on Draw Normals in the right MeshTool window.)
  7. Now you can set smooth and… voila, a basic smooth tube.

That’s it. Two last tips:

  1. Don’t use Boolean modelling if you don’t have to.
  2. Watch out for long triangular faces which may give bad results

Goodluck

3

yes, greybeardy mentioned it creates artifacts - in one of his video tuts. what are artifacts?

4

Umm-kay…
I created the tube like you recommended… but after I added the lop-sidedness that I’d had before with my Boolean-Op. mesh… I now get what looks like a strain-mark on one side when I render. Do you know the cause?

Okay… here’s the image that I’m getting:
http://www.geocities.com/cronocat0/stretchmark.jpg

And the file is under the same name, but updated:
http://www.geocities.com/cronocat0/spikey.zip

5

Try Ctrl+N, that usually gets rid of that for me.

6

Yes,
that’s right I made a little failure in my first explanation. Under point 6 it should say: press Ctrl-N to recalculate normals outside.

7

Okay… I tried it… the recalcing the normals… but it didn’t help – there’s still a streak that won’t react properly to light – anybody have any suggestions?

Updated with recalced normals:
http://www.geocities.com/cronocat0/spikey.zip

8

try clicking on ‘auto smooth’

9

I checked your model and indeed al the normals were correct. I started trying things and came up with this simple solution.

  1. Select the tube, and go into edit mode.
  2. Select all vertices.
  3. Press F9, in the Mesh Panel push Double Sided to off.

That should solve your problem.

10

Alright, it worked. Thanks for the tips.