I’ve noticed a strange thing just as I started working on a new model.
I start off with a simple plane that has been rotated. While extruding an edge, the edge normal points into some odd angle, and therefore the edge get’s extruded along that. Now, this doesn’t happen if I do the same in vertex mode.
Is this some weird but intended behavior, or simply a bug?
What I do:
Start with a fresh blend file
Delete the cube
Add a plane
Rotate the plane by 90 degs around the Y axis (same thing if you rotate in edit mode)
Go to edit mode
Set edge select mode
Select either of the side edges
Switch to side view, extrude and CTRL+drag some where the new edge.
The new face will be out of plane.
I’ve got the same problem. Blender 2.53, rev. 31745
Intentionally thought about some problems with the normals. But recalculating them didn’t fix the problem at all.
While extruding, in top view, you can see that the extrusion axes are rotated very weirdly.
I think how “along normal” works for edges is it uses the angle of the edge and keeps the extrusion on a perpendicular axis (I’m probably screwing up my terminology there). If you try to look at the plane from an angle (slightly above or below), you’ll see that one axis is locked (there are two white lines on the screen instead of one), and the edge is following that locked axis but travelling in the other 2 axes.
If you keep extruding the same edge along normals from all sorts of angled views, you’ll see that every resultant edge is parallel to the original edge even if you started with some wierd angle and extruded it all over the place.
If you hold down the middle mouse button and drag while it’s set for normals, you can actually switch which normal you are sticking to (X normal, Y normal, Z normal) by dragging around until you see the normal you want in the bottom right corner.
Oh, yeah. It’s true what Haledire mentions. What did we all learn in our analytic geometry classes? What is the normal of a straight line in the R³?
Right, there is an infinite number of normals, hence the extrusion must be working properly. If you first type “e” for extrude then “y” for the y-axis, then you are fine. I didn’t even notice the fact (maybe that’s due to my first year of “higher math” education). This could be the reason - what do you think?
I learned I could switch the “along normal” direction with the middle mouse only today, I did not know that until I accidentally came across it while trying to come up with the answer to this situation.
Now if someone could tell me if there’s a way to actually switch back to normal direction after canceling it, my day would be complete (and yet, I feel there shall be no salvation…)
