## Using Geometry Parts and Part Libraries in COMSOL Multiphysics®

##### Magnus Ringh February 22, 2019

Using geometry parts, created by you or added from any of the part libraries available with the COMSOL Multiphysics® software and some of its add-on modules, can greatly simplify and streamline the construction of more complex geometries for your simulations. Here, we show you how you can add and make use of geometry parts and create user-defined part libraries.

### Performing Topology Optimization with the Density Method

##### Kristian Ejlebjærg Jensen January 4, 2019

Engineers are given significant freedom in their pursuit for lightweight structural components in airplanes and space applications, so it makes sense to use methods that can exploit this freedom, making topology optimization a popular choice in the early design phase. This method often requires regularization and special interpolation functions to get meaningful designs, which can be a nuisance to both new and experienced users. To simplify the solution of topology optimization problems, the COMSOL® software contains a density topology feature.

### How to Use Interpolated Material Data to Model Irregular Geometries

##### Hanna Gothäll March 20, 2018

We have already discussed different ways to create geometry objects of irregular shapes on the blog. In this blog post, we will demonstrate an incredibly powerful alternative approach by using interpolation functions. Instead of creating geometry objects, we will indirectly define the irregular shape by taking advantage of the spatial variation of a material property in the object we want to study.

### How to Build Geometries from Elevation Data to Model Irregular Shapes

##### Hanna Gothäll December 19, 2017

In Part 2 of our blog series on how to model irregular shapes in the COMSOL Multiphysics® software, we focus on how to create a surface of an irregular shape based on elevation data stored in various formats such as text, an image, or a DEM file. This approach is best suited for data where the height (or elevation) is a function of x– and y-coordinates.

### Modeling Irregular Shapes: How to Import Curve Data and Loft a Solid

##### Hanna Gothäll September 20, 2017

Irregular shapes can come in several different formats. For example, we have previously discussed importing STL files and NASTRAN® meshes into the COMSOL Multiphysics® software. These formats are common when working with scanned biological data. In this blog series, we will look at different ways of handling irregular shapes in COMSOL Multiphysics.

### Creating a Model Geometry in COMSOL Multiphysics®

##### Amelia Halliday June 29, 2017

Creating the geometry for your model is one of the first steps of setting up a simulation. In the COMSOL Multiphysics® software, there are many geometry operations, tools, and functionality that enable you to do this. These include geometric primitives; Boolean, partition, and transformation operations; work plane operations; and other CAD tools. Here, we highlight all of this functionality and, near the end, link to a video tutorial series that shows how to use them while building your model geometry.

### How to Create a Randomized Geometry Using Model Methods

##### Walter Frei June 5, 2017

Have you ever wanted to include a randomly created geometry in your model? Perhaps you want to simulate a natural material or an arrangement of parts that has some known statistical distribution of dimensional variations. In such cases, we may want to create a random geometry in the COMSOL Multiphysics® software. With the release of version 5.3, we can now create random geometries using a method. Let’s take a look at how to do so with a tasty example.

### How to Generate Random Surfaces in COMSOL Multiphysics®

##### Bjorn Sjodin June 2, 2017

To easily generate random-looking geometric surfaces, the COMSOL Multiphysics® software provides a powerful set of built-in functions and operators, such as functions for uniform and Gaussian random distributions and a very useful sum operator. In this blog post, we show you how to generate a randomized surface with what amounts to a “one liner” expression with detailed control of the constituent spatial frequency components that determine the nature of the surface’s roughness.

### How to Use Topology Optimization Results as Model Geometries

##### Hanna Gothäll February 1, 2017

Topology optimization can be a useful step in your design process, but the generated designs often require further analysis. With the COMSOL Multiphysics® software, you can create geometries out of your topology optimization result plots and easily export them to CAD software. In this blog post, we discuss how to do so, using both 2D and 3D examples.

### Efficiently Assign Materials in Your COMSOL Multiphysics® Model

##### Amelia Halliday September 20, 2016

To optimize your modeling processes, there are a number of built-in materials available for you to use in the COMSOL Multiphysics® software. Along with these materials are features and functionality that allow you to efficiently assign materials to geometric entities in your model. These tools help expedite the process of assigning materials, specifying material properties, and even comparing the impact of different materials on your simulation results. Here, we’ll highlight three tutorial videos that showcase how to use such tools.

### Improved Functionality and Tips for Importing STL and NASTRAN® Files

##### Hanna Gothäll September 14, 2016

STL files originating from 3D scan sources and meshes in the NASTRAN® file format are often used as bases for geometries. However, performing simulations on these realistic objects can be challenging, particularly when preparing the geometry. The COMSOL Multiphysics® software contains features for dealing with these files. Learn how to utilize this functionality as well as how to achieve good results when importing STL and NASTRAN® files.