I wish to visualize geometric problem.
e.g. I wish to draw few transparent Ellipsoid surfaces.
I found sphere, box primitives but I can find ellipsoid.
Do I just scale sphere to get ellipsoid?
If yes then What if I need hyperboloid? Is there way to generate primitive programmatically? (instead of exporting from Blender or 3D Max)
You can generate any mesh you want programmatically by setting mesh.vertices: Unity - Scripting API: Mesh.vertices
Full examples are included in Procedural Examples | Tutorial Projects | Unity Asset Store
You’re thinking of it the wrong way. As a game engine, Unity expects you to import your own textures, sounds and 3D/2D models.
For people just wanting to try out the system, they have the cube, sphere … , a simple particle-ball texture, even some grass textures in the terrain package. But “everyone” knows the Assets that come with a game should never be used for real. You should use your own bevelled and/or diff UV’d cubes, more/less grained isospheres, and so on.
So, the real question is “how do I get an ellipsoid model in Unity?” And the answer is that you make and import it, the same as everything else. Sure, maybe you can turn their sphere into one, but, in general, don’t expect a game engine to provide any “real” assets.