# 2D sheet of circular ring

In the FDTD cad, 2D sheet of rectangle and polygon structure is given. But how to make 2D sheet of circle ring or circular arc for graphene material.

Dear @eez158093

For slightly complicated structures, you can use scripting language and defines the vertices for your objects, and then set vertices. The link below has some examples (including ring and circle) for your review:

https://kb.lumerical.com/en/index.html?ref_sim_obj_structures_2d_polygon.html

Thanks

A post was split to a new topic: When to use single layer graphene model for multiple layers?

How to make a 2D sheet like shown in the figure for graphene sheet?

Dear @eez158093

While you might be able to construct this ring (maybe by a 2D rectangles with surface normal of x that are rotated along z-axis), our software is only capable of handling flat graphene layers (i.e. graphene is aligned with x,y, or z axis).

Keep in mind that, because the graphene material type generates a surface conductivity that corresponds to a flat surface, it can only be used with geometric structures that represent flat surfaces.