false.
a face is a triangle. However is a polygon is any n-side figure. Polygons are made up of triangles(the equation to know how many triangles make them is N-2 (5 sided polygons have 3 triangles)). You should have it in mind. Polygons classify in tris (triangles), quads(4 sided polygons) and polies(N-sided polygons with more than 4 sides). In wc3 there are 2 types used, tris and quads. Tris or triangles are used in geometry and unwraps, while quads are used in particle emitters.
Anyways, optimizing a mesh has 2 processes: An automatic process and a manual process.
the automatic process consists on software enhanced poly reduction. In 3dsmax there are 2 modifiers specially designed for that: Optimize and MultiRes. The first one is a full automatic reducter, it will look for reductable faces and edges instead of vertices. The second one is used for very high poly models, it tries to reduce multiple vertices which follow the same pattern. The second one is in part manual as you select vertices which are applied with multiresting.
The manual process which is the best consists on collapsing vertices, welding vertices, targetting, slicing, restructuring, retriangulating and even recreating geometry. It's an slow process but it's the best that there is. Pretty much is hard to explain this since it's something very subjective to the artist and his perception of shape. You should try doing some modeling for attempting reductions.
Pros & Cons.
Pros:
- Geometry is more optimized and cleaner(if done manually).
- Optimized meshes are easier to edit and unwrap.
- Skinning(attaching mesh to bones or muscles) optimized meshes is a lot easier.
- Smaller filesize.
- Increases rendering performance and makes Z-buffering faster.
Cons:
- Quality Loss.
- May fuck up unwraps (unless your software applies optimizations to the unwrap as well)
- Smoothing groups get owned.
- Bump maps may need some tweakings. (depending on the bumping technique used)
- Animations bend less naturally.
- Skinning may have conflicts on Limb subdivisions.
Hope this served as a introduction.
