Wings

Support Modeling
1

Hello

I just got started with blender and try out a wing to use in a presentation. When I get it in smood something strange appears on some parts of the model. I can’t find anything wrong on the vertiges or edges…?
I somebody can give some a suggestion???

Thanks

Attachments

SFG Kenteken.blend (410 KB)

2

Decide whether you want to use flat or smooth shading, your object consists of both. Select your object and press the appropriate button in the toolshelf (T).
Then you need to correct your face normals. You have some faces pointing inwards and some pointing outwards which gives dark shading artifacts as you try and smooth shade between these faces. In edit mode select all the vertices (A) and recalculate normals with Ctrl+N

3

There are 89 non-manifold elements, 2 interior faces and 85 triangles in your model.
[ATTACH=CONFIG]192421[/ATTACH]

You’ll find those by unselecting everything in edit mode and then select either interior faces or non manifold from the select menu.

4

hey
Thanks for the reply. But what’s the negative impact of ‘non-manifold’ elements, interior faces and triangles in this project. Does this means I have to avoid triangles and interior faces?
I’m Belgian and speak Flemish so I did try to translate ‘manifold’ in this context…I’m afraid my level is to low to get get it for now.
But thanks for help.

grts, MAki

5

Google “non-manifold” and “non-manifold mesh” to get an explanation of what it means.

They cause shading problems. Here’s couple of examples from your mesh.

[ATTACH=CONFIG]192627[/ATTACH]

From top left:

  • I set the shading to smooth and recalculated normals but those faces are still black.
  • Edit mode, selected non-manifold and put the face normals display on. The face normals that would appear in the middle of the face don’t show up correctly and there seems to be extra face normals coming through weird places.
  • There are interior faces. I selected the inside edges to show they are connected through the mesh and then deleted them, getting rid of the inside faces
  • Now the normals recalculate correctly and no reversed faces that show as black

[ATTACH=CONFIG]192628[/ATTACH]

Another one, from top left.

  • Shading cuts horizontally
  • Selected non-manifold elements and put the vertex display on. Looks ok (even though that would mean couple of n-gons) but
  • looking more closely reveals there are holes
  • Cleaning the topology. Connecting the topology gets rid of the shading problem

It’s not so simple to answer that. For interior faces, yes, you should avoid them at all times.

Non-manifold elements and triangles - you should use them in places where you know they’re not going to cause problems. I’m not going to go too deep in to triangles because there are holy wars about triangles in here. What you should know is that when modeling, they terminate edge loops and can cause shading problems in the wrong places when using subdivision surface modifier.

[ATTACH=CONFIG]192650[/ATTACH]

Row from top to bottom: edit mode with non-manifold elements and interior faces selected, mesh with subdivision surface modifier (level 2 subdiv) and smooth shading, mesh with smooth shading (without subsurf).

From left column:

  • Cube with clean topology
  • Cube with interior face - with subsurf, a huge problem, a bit of shading problem without it
  • Cube with unconnected edges and one of the edges is subdivided - deformation problem with subsurf, obvious shading problems without it
  • Cube with a rectangular hole and extruded inside, detected as non-manifold - doesn’t cause a problem if it won’t show in render
  • Cube with a hole in it and with created thickness - no problems, except that you might not want thickness for this object if the insides aren’t going to be seen.
6

Amazing
thanks so much for this explanation and the time you’ve put in it. I will work on it the rest of the day and hope to finish the movie project end of this week. I send you the end project when finished. I guess this will not be the last problems i will have to face but it sure motivates me.
grts, Maki