# Documentation

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# 2-D Geometry

Define 2-D problem geometry

For 2-D problems, you can create 2-D geometry via the constructive solid geometry (CSG) or the geometry function approach. Using the CSG approach, you can use a set of solid building blocks (square, rectangle, circle, ellipse, and polygon) and combine them to define complex geometries. For details, see Create 2-D Geometry.

The PDE Modeler app uses the CSG approach. For details, see Create 2-D Geometry in the PDE Modeler App.

## Functions

 `geometryFromEdges` Create 2-D geometry `importGeometry` Import geometry from STL data `pdegplot` Plot PDE geometry `decsg` Decompose constructive solid geometry into minimal regions `csgchk` Check validity of Geometry Description matrix `csgdel` Delete borders between minimal regions `pdearcl` Interpolation between parametric representation and arc length `wgeom` Write geometry specification function
 `pdeModeler` Open PDE Modeler app `pdecirc` Draw circle `pdeellip` Draw ellipse `pdepoly` Draw polygon `pderect` Draw rectangle

## Properties

 AnalyticGeometry Properties 2-D geometry description

## Topics

### Programmatic Workflow

Create 2-D Geometry

Choose an approach for creating a 2-D geometry.

Create CSG Geometry at the Command Line

Create a 2-D geometry by using the constructive solid geometry (CSG) modeling approach.

Create Geometry Using a Geometry Function

Describe a 2-D geometry by using a parametrized function.

### PDE Modeler App Workflow

Create 2-D Geometry in the PDE Modeler App

Create a 2-D geometry interactively by drawing, rotating, and combining basic shapes.

Rounded Corners Using CSG Modeling

Represent a geometry with rounded corners (fillets) by using the Constructive Solid Geometry modeling approach.