The process of finding N-Sided or multi-sided polygons that have more than 4 edges can be difficult. Arvid Schneider explains how he finds these offending shapes in Maya using selection constraints to easily highlight them for editing by hand, if need be.
…With this video I want to show you how to remove n-sided polygons, ngons from your meshes…
Arvid also shows some techniques for dealing with N-sides in Maya by manually adding edges to re-configure how the N-Sides are affected or using a cleanup dialog that automatically changes configurations.
Arvid notes that “In some occasions especially in real-time engines, ngons are so to speak the devil. In a very detailed mesh it’s hard to see them and remove them which is why I want you all for this neat trick! You can select specific faces like pentagons or triangles with ease using something called magic brush tool.”