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Extrusion is our primary means of adding additional geometry to ameshin Maya.
Extrusion
On the left, we started with a plain old default cube primitive.
A manipulator will appear, which looks like an amalgamation of the translate, scale, and rotate tools.
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Notice that there’s noglobal scalemanipulator at the center of the tool.
This is because the translate tool is active by default.
To turn the option off, go to theMeshmenu and uncheckKeep Faces Together.
Use the Extrude tool to “pull” new faces out of your mesh.
Look at the image above for a comparison between the two types of extrusion.
Both objects began as a 5 x 5 polygon plane.
Performing edge extrusions with keep faces together turned off can produce somevery, verymessy results.
Turning off “Keep Faces Together” leads to a much different result with the extrude tool.
However, when used carelessly the tool can inadvertently produce a relatively serious topology issue callednon-manifold geometry.
The most common cause of non-manifold geometry is when a modeler accidentally extrudestwicewithout moving or scaling the first extrusion.
To Troubleshoot Non-Manifold Geometry:
Knowing how to spot non-manifold faces is really half the battle.
Non-Manifold Geometry is a common pitfall for beginning modelers because it is so difficult to spot.
To do so, go toWindows tweaks/Preferences tweaks Selection Select Faces With:and chooseCenter.
Surface Normals
One final concept before we move on to the next lesson.
Normals in Maya are invisible unless you explicitly change your display tweaks to reveal them.
Turn off Two Sided Lighting to see the surface normal direction of your mesh. Reversed normals appear black, like the image above.
With Two Sided Lighting turned off, reversed normals will appear black, as shown in the image above.
That’s all for extrusion (for now).
In the next lesson, we’ll cover some of Maya’s topology tools.
