Re: [Libmesh-users] normals

[Roy S. <roy...@ic...>]

On Wed, 21 Dec 2005, Roy Stogner wrote:

> On Wed, 21 Dec 2005, Michael Povolotskyi wrote:
>
>> I don't mean to flip, I mean to change order:
>> {1,2,3,4} to {4,3,2,1}.
>> Can this change the direction of the normal?
>
> That will give you an inverted element, won't it?  I think libMesh
> assumes that QUAD4 element nodes are numbered clockwise; you may be
> getting negative Jacobians, not just inverted normals.

Counter-clockwise, I mean, counter-clockwise.

In fact, don't take my word for it either way; check the diagram in
include/geom/face_quad4.h for yourself.  ;-)
---
Roy Stogner