# Geometry

A geometry describes a shape. It represents the structure of an object through data such as:

- Vertex positions
- Normals
- Texture coordinates (UVs)
- Indices
- Topology information

A geometry contains no visual appearance. 
It does not define color, shading, lighting response, or rendering behavior.
Instead, it describes where points exist in space and how they connect.

Geometries can be:

- Procedurally generated (e.g., box, sphere, cylinder)
- Imported from external files
- Constructed manually from vertex data
- Derived from mathematical functions or parametric equations

Geometries will be our gateway to simulations.

## File Formats

In computational systems, geometries must be stored in standardized formats.

One common format is **STL** (STereoLithography), widely used in 3D printing and CAD workflows, and is the **standard format used by Aerosim**.

STL represents geometry as a collection of triangles. Each triangle is defined by:

- Three vertices
- A surface normal

It does not store materials, colors, or textures (in its basic form). It purely represents surface approximation.

In engineering and simulation contexts, geometry often begins as a continuous mathematical model and is later converted into a mesh - a discretized representation composed of elements (typically triangles, quadrilateral or hexagon) suitable for rendering or numerical computation.