I just found myself have trouble in creating kind of complicated 3D object such as semi-sphere or pyramid, etc. Does anyone know how to do it?
Unity is not a modelling application, it’s a game engine. You have to create your models in a modelling application and import the model in Unity. Unity only has a few primitive meshes included in the engine. Anything more complicated would need to be created externally and imported or if you’re familiar with how a mesh is build you can use the Mesh class to create a mesh procedurally