View Full Version : Extrude Face funkiness

06-22-2009, 03:30 PM
Try this experiment.

1. Create a Poly plane with 1 sub division for height and 1 subdivision for width
2. Extrude the plane either up or down
3. You get a closed box (6 square polys), correct?

4. Ok, now create another Poly plane, this time with 3 sub divisions for height and 3 sub divisions for width
5. Select faces and extrude the middle face either up or down.
6 Notice that you get an open box or a hole dipped into the plane.

Why is this and what governs it? Keep faces together does not solve this issue.

I ask this because I have a model where I am trying to extrude existing polys such that there are polys on all 6 sides. However, Maya will only push the existing faces outwards, creating 5 sides with polys, like the open hole issue above.

Any one know of a toggle for this?

06-22-2009, 05:25 PM
That's the way the extrude tool works. What you're looking for is something completely different. Might check highend3d for some scripts.

06-22-2009, 11:12 PM
Yeah it's definitely just how the maya extrude tool works. Because generally when extruding out from an object you want to have a hollow middle not a covered hole on the inside. Maybe there's an extrude tool option, but sorry I feel like there's not.

06-22-2009, 11:52 PM
...Why is this and what governs it? Keep faces together does not solve this issue... When you extrude a whole object, Maya can define which is the inside and outside of the geometry (you can check this by the face normals).
When you extrude only some faces, and fill the back of the extursion you are creating nonmanifold topology which is problematic in many cases.http://download.autodesk.com/us/maya/2009help/images/MED/MacGyver/English/Glossary/comp_nonmanifold.png

Anyway, if you want you can fill the holes. One way would be first to use Mesh > Extract without 'Separate extracted faces' checked in the options. Then extrude, and finally merge the separated vertices.

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06-22-2009, 11:52 PM
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