Extruding along a varying edge?


I started using blender earlier this week and I am loving it. I have already spent a lot of hours and the learning curve is very steep.
I am modeling an aircraft wing at the moment. The trailing edge is very curved at one section and I would like to extrude the trailing edge of the first rib along that curve. It will have to scale as well.
I would like the new longitudinal edges to be 90 deg to the current lateral edges.
Is there an easy way to do this? (See pic)

Thanks for your help!


Could you photoshop in some arrows and maybe painted example of what you are trying to achieve? Your explanation is a bit hard to follow.

When I made a wing I used Subsurf modifier for smooth flowing shape. Edge crease can be used for sharp edges on a subsurfed model.

I realize that it is a little hard to explain what I am trying to do.
I want to extrude the 4 selected vertices along the edge in the picture. As you can see, the edge is curved and it gets more narrow towards the end.
Thanks for your help.

Here you go… Bsurfaces.

First, make half circles at each loop - select 2 vertices upper, lower, adjust view so that half circle fits. Do this for each wing loop and make sure each has same amount of vertices.
L select all half circle vertices starting from one end, separate into another object. Convert to curve. Set curve type to be Bezier in edit mode and check that all curve normals go one direction.

In Obj mode select curve , Shift select wing and tab into edit mode. Select wing tip edge loops, press button to create surface (hope your Addon is checked already).

To smooth out some use Loop Tools Addon.

Based on your question you’re either new to 3D or new to polygonal modeling. Those are not spesific to Blender. Blender use becomes easier fast but you still have many mountains to climb with the concepts of polygonal modeling, texturing etc.

Edge select mode (ctrl+tab), select the edge marked with cyan color, ctrl+alt+space to create a custom transform orientation (TO). This also automatically switches global/local TO to global/edge on the 3d view header. After that, vertex select mode, select the (scaling) target vertex from already made point, shift+S -> cursor to selected. Then switch pivot to 3D cursor (period key), extrude (E), cancel transformation (right mouse button), and scale along edge, excluding one axis: In the example pic I did S, shift+X+X.

S is to scale, shift+axis is to exclude an axis. Selecting an axis gives the global axis but pressing it the second time gives the custom transform orientation, that’s why shift+X+X.

You could also enable vertex snapping (ctrl+shift+tab) before scaling and if you then scale as mentioned and also hold down ctrl and point your mouse to the vertex where the 3D cursor is, you can snap to 90° angle (to the current transform orientation).
If that is not what you want, then you have to eyeball it because snapping functions doesn’t support other kinds of intersections between snapping element and transform orientation.

Maybe you could use temporary geometry to get face angles displayed (properties panel in edit mode (N) -> mesh display -> face angle) but the point is, you shouldn’t try to make it that precise. If pinpoint precision is what you need, then you’ve chosen the wrong modeling paradigm.

Yes, and that would be to start with a very simple approximation of the whole wing and then put in the detail.

Interesting that there should be two such different interpretations of your request! I’m not convinced that either one reflects what you originally wanted - what rib?- so at the very least you should consider making your requests - either this one or future ones- clearer, to save your own, and others’ time! Some ways to do this - show a reference photo or drawing, perhaps with the areas of interest highlighted and marked. Show the corresponding part of your model with desired geometry drawn onto the screenshot.

If top and bottom edges have the same amount of vertices, and if those rounded opposite edges have too the same amount of vertices, you can use the grid fill tool that while it got an upgrade in 2.6 still have the previous functionality functioning

select both opposite side edges

And press CTRL+F -> Grid Fill

I’m sure there are many more interpretations.
Like it is the case with many new users, explanation of what/where/why are lacking clear visuals. If there is a problem with the settings and it’s described with a screenshot, that screenshot is often cropped to only show the symptoms, or the screenshot is too small, or both. That makes the informational value close to 0.

There are options when reading such post

  • close tab
  • ask (gently) more information, which is not very effective in many cases
  • bluntly but very clearly tell the provided information is useless crap, and also what and how to communicate instead
  • if the starting post doesn’t provide visuals/file, answer without giving visuals/file
  • just play with Blender a bit and post a reply. If it’s not a direct/correct answer to the question, the information could still be useful. At least more so than what the first option provides.

More information was already requested so I went for the last option :slight_smile: But really, I choose the first option quite often, most of which include Richard telling the op to include visuals/file.

(Here is an example of background information when a pro user asks a question that is a bit hard to explain)

First of all apologies for my vague description of what I wanted to do. However, both eppo and sanctuary solved my problem - so thanks very much! Also thanks to JA12 for his answer, although I am not sure if quite answered my question. There was still some good info in the reply.
I am away from my blender computer for two nights at the moment so I will have to wait to try the techniques until I get home.

I did manage to solve the problem myself by extruding each individual vertice towards guide lines that I connected between the two ends. It was very time consuming but I got there in the end.

Thanks for your help everybody!