QUAD Face Constructor BUG

One for David, there is a bug for the construct quad face. The default vertex numbering is set to 0;1;3;2 instead of 0;1;2;3. I had a large mesh model i was constucting that was composed of 2000 individual meshes with one quad face and 4 vertices. It could not construct the mesh as the face constructor was default to 0;1;3;2. See below

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Replies to This Discussion

Permalink Reply by David Rutten on December 24, 2013 at 3:20am

You mean a bug, or you just don't like the default values?

The reason it's 0,1,3,2 rather than 0,1,2,3 is that represents the more common case. When you make a mesh quad grid, you tend to number the vertices per row, then switching to the next column:

When you take the simplest case (one quad, four vertices, two rows, two columns) you get this:

The vertex order for this quad is {0,1,3,2} or {0,2,3,1} for a quad pointing the other direction.

David Rutten

david@mcneel.com

Permalink Reply by Steve Lewis on December 24, 2013 at 5:18pm

Ok thats news to me, it maybe a architectural or computational thing, but the reason i raised it was as far as i aware all fea engineering analysis programs, require one to construct a face with connectivity of vertices ordered sequentially, the order defining the direction of the normal, using 0 1 3 2 Causes an error this way. If it a quad face it seems odd to me that you would label the vertices in such an order, as an engineer, i have never seen it done as 0 1 3 2, it could be 3 2 1 0, 2 1 0 3 etc but going 0 1 3 2 is not acceptable, i will do a bit more reading on this.

Permalink Reply by Luis Fraguada on December 24, 2013 at 6:52pm

In all my mesh building, I always seem to get the points in 4 groups and change the quad face component to {0,1,2,3}. Actually, if I remember correctly, the mesh component has such a quad face as the default face input.

Permalink Reply by Steve Lewis on December 24, 2013 at 7:00pm

So u seem to have the same issue as me then? I have to explicitly change it to 0 1 2 3, the default is not this it is 0 1 3 2. Converse for a tru face it is as expected, default is 0 1 2.

Permalink Reply by Luis Fraguada on December 25, 2013 at 8:58am

Are you using the Construct Mesh Component? It's default face is already set to {0,1,2,3}: