Problems with twisted faces continue.

Support Basics & Interface
#1

Hi

Can anyone suggest what’s causing the twisted faces and i don’t mean flipping normals on a face:

http://yellowsblog.wordpress.com/files/2005/12/twisted.png

http://yellowsblog.wordpress.com/files/2005/12/twisted2.png

This is a model of a window, yet the window frame has got a bevelled appearance and some of the faces are twisted, as if one of the vertices is upside down causing the gradient effect from the corner of a face. The images show a mild example of what is becoming a real pain.

The window was created from a DXF import of 2D geometry (ie. s flat mesh) and then edges/verts selected and ctrl f to create faces and the edges extruded to give the window frame depth.

http://yellowsblog.wordpress.com/files/2005/12/twisted3.png

Many thanks.

#2

Can you post a picture with the normal vectors visible? Also, is the mesh set to smooth shading, instead of flat?

#3

Waffler:

http://yellowsblog.wordpress.com/files/2005/12/twisted5.png

And the look of the object:

http://yellowsblog.wordpress.com/files/2005/12/twisted4.png

thanks

#4

Those two faces appear to have normals pointing inwards. Recalcing (ctrl-N) should fix.

Also if you are rendering with ambient occlusion and you have multiple faces on those vertices you can get rendering artifacts, but I don’t think this is the case here. Recalcing normals should work if not just do it manually with the button that says ‘flip normals’.

#5

forTe:

crtl n and flipping them manually is just moving the problem about and the two faces in particular get gradients in both directions by using ctrl n, flipping them makes no difference.

As i’m creating faces from imported vertices/edges, i guess the normals problem is result of the imported vertices pointing in different directions? Although i can’t tell that.

Is there a function or script that can clean up the flat imported mesh before i start creating the faces and extruding?

thanks

#6

crtl n and flipping them manually is just moving the problem about and the two faces in particular get gradients in both directions by using ctrl n

When this happens you have a non-manifold mesh. Select all verts and remove doubles (w->remove doubles) and then look for interior faces. A way to help track them down is with the select -> non-manifold command.

GreyBeard

#7

You have non-manifold faces in your model. Those faces that exists INSIDE the model. Delete those faces and your problem should go away.

#8

GreyBeard & grafix:

Many thanks, i’ve looked at the non manifold stuff but it still not solving the problem. So i went back over the way I’m creating the window and if i remove doubles and then extrude the mesh before adding faces all is well and i don’t get the problem.

many thanks