# COMSOL Learning Center

## Learn How to Use COMSOL Multiphysics® at Your Own Pace

### Geometry / Change 3D Geometry into 2D

Extract and build 2D models from 3D geometries. Duration: 7:58

One of the first steps for creating a model is to build the geometry. In the COMSOL Multiphysics® software, you can use a range of tools, operations, and functionality to create the geometry for your model. There are specialized tools for generating certain types of geometries, such as those obtained from cutting through a solid by a plane.

In COMSOL Multiphysics®, you can create 2D models from 3D geometries by using work planes along with the Cross Section geometry operation. This enables you to extract a cross section from your geometry and create a 2D model based on your 3D model, significantly reducing the computational time and memory required to solve your simulation. The functionality is useful when working with:

• Symmetric or axisymmetric 3D geometries, in which you can obtain quicker solutions for the same geometry
• Thin-walled parts, in which you can use the plane stress assumption for your 2D model
• Long parts, in which you can use the plane strain modeling assumption for your 2D model

In this video, we show you how to obtain a 2D geometry from a 3D geometry using a light bulb model as an example. We first show how to obtain a 2D cross section in general and then discuss how further geometry preparation may be necessary to obtain a suitable cross section, especially when working with axisymmetric geometries. We then demonstrate how to prepare the 3D axisymmetric geometry of the light bulb in order to obtain the appropriate cross section for the 2D axisymmetric model equivalent.

##### Exercise Files
3d_to_2d_build_complete.mph
3d_to_2d_build_start.mph

### Geometry

Videos: 6

##### Further Learning Resources
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