A circle (Mesh object) only shows the outline. A plane (mesh object) showed up properly. How can I make this circle look like a plane? When I switch to the edit mode, the circle is shown with vertices unlike a plane. Please advise me how to fix this issue so that a circle will show up properly.
By default blender doesn't fill the circle. There are two types of fillings for circle. You can do it either manually or select it from the pop-up menu that appears when you add in the circle. The two types of filling are:-
In this type of filling it'll just add in a single face.
2. Triangle Fan
In this filling, there is a center vertex which is connected with all other outer vertices.
In this type of filling you can easily add in circular loopcuts to add more geometry if needed.
You can manually model it by selecting all vertices in edit mode with A fill it usually with F and navigate to Face > Poke Faces OR select it from the pop-up menu.
Selecting between this two fillings depend on when and where you use it.
I think the word "circle" in this case means the closed curve that is made of points that are all the same distance from the center. So it is a curve because it is supposed to be just a curve. It would probably be more correct to call the area of a plane that is limited by a circle a disc. So I think in a mathematical or geometric sense this is correct - if you want to create a circle and choose this option from the menu, it should create a circle and it is just a curve.
The reason behind Blender having a circle as opposed to a disc or something else as one of the basic 3d primitives is another question. This question is a bit harder to answer. Thinking logically, it is hard to come up with a definite reason why it should be this way and not another and it might be that there is no definitive logical reason why it is this way. We might as well have a disc instead of a circle or have both of them, but it just happens to be what was chosen by whoever was programming this and since it is so easy to fill it with just pressing a followed by f after entering edit mode(Tab), there is probably little reason for developers to put much more thought to this.
In Edit Mode select all A and make a face F .
A circle is just 360 deg vertices with however many vertices you selected. In the bpy module you can see it draws a fill for cubes by connecting different edges but the circle is just one edge bending around which is why it may not fill automatically. I'm not sure though.