A bit not typical question but it bugs me - why build in Plane object consists of so many triangles instead of just 2? Besides wasting GPU, what’s the reason?
There’s no “industry standard” for the number of triangles in a plane. The one in Unity just happens to be a 10x10 grid, so has 200 triangles. If you need a two-triangle quad, then either create one, use the GL.Quad primitive, or wait for 4.2 which will have a Quad game object to live alongside the plane, sphere, capsule, cylinder, etc. Note that when you do GameObject->Create Other all that happens behind the scenes is an empty game object gets created, and then a model is pulled out of some resources the editor has, and components are added to it. There’s no magic.
Also seems odd that cubes are 1x1x1, spheres are diameter 1, but planes are size 10x10. I assume because planes are typically used for large walls and floors, so new users find it easier. As Graham writes, everyone else will import their own planes.
It’s kind of understood that the built-ins are just messing around assets. Even something as obvious as a cube gets replaced with a differently UV-mapped cube to make crates.
A typical messing-around use for planes is to test out vertex deformation shaders – water and such. I’d say 11x11 verts is about the right size for that.
You can get some approximation of spotlights/point lights when using vertex lighting on a plane that has many polygons.