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How to build a parametric model in OnScale Designer

By Chloe Allison 04 February 2020

This blog post describes OnScale Designer, our graphical user interface (GUI), and how it can be used to build a parametric model.

To get the most information from a simulation, parametric analysis is key. Designing a model using parameters allows engineers to simulate multiple different scenarios with minimal effort and see the effects of design changes quickly. This feature coupled with OnScale’s scalable cloud high performance computing (HPC) allows designers to perform large parametric studies and design optimization quickly and easily.

OnScale Designer is an accessible but powerful graphical user interface for building models. Users can build models using primitive shapes and/or CAD geometry.

Parametric Model

Figure 1: The OnScale Designer GUI

The Designer workspace consists of several windows.

The Model View provides an interactive space to view your model. You can explore the model by zooming, panning and rotating. The Model View is a visual representation only. The model can be edited using the Model Tree and Properties windows.

To create a model in Designer, go through the Model Tree from top to bottom, adding in the different components of your model from assigning materials to meshing to adding outputs required from the simulation. The Properties window shows the properties of the component you have selected in the Model Tree and is used to edit these. For example, if you select a load in the Model Tree, you can specify the type of load, drive forcing function, amplitude and time shift in the Properties window.

The final window in the Designer interface is the Parameter Table, which is used to manage parameters.

Figure 2: Parameter Table

Parameters can be input into the table by defining a name and value for the parameter and then clicking the + button or pressing Enter. Parameters can be removed using the button.

Parameters can be entered as real numbers, integer numbers or equations. For a parameter to have integer type its name must begin with the letter i, j, k, l, m or n. Any other parameter is considered as real. To enter an equation into the Parameter Table, the first character must be = followed by the equation. A full list of parameter table functions can be found here.

Equations can reference other parameters in the table if these dependencies are above that parameter in the table. Parameters can be moved up and down in the table using the up and down buttons. If you want to run a parametric sweep on the cloud, you must select the Varying checkbox for any parameters that are to be changed.

Parameters are applied to the model in the Properties window. A number of model components can be parameterized in OnScale, for example primitive shape dimensions. To parameterize a model component, select this component in the Model Tree and, next to the property you want to parameterize, click the  icon and select Use Parameter for Property. You will see a dropdown list of all the parameters and their current values to select from.

If you are parameterizing your model dimensions, be sure to do the same for other components of the model which vary with the dimensions, such as model extents, loads and output locations.

Once you have a parametric model set up in Designer you can run hundreds or thousands of variations of the design on the cloud via the Cloud Scheduler.

Figure 3: Cloud Scheduler

In the Cloud Scheduler each parameter can be swept from a start value to an end value for an increment value. Alternatively, a CSV (comma-separated values) file can be used to drive a sweep with the parameter values set for each simulation.

Try working through our Beginner’s Designer Tutorial to see how to set up a basic parametric model in Designer.

Chloe Allison
Chloe Allison

Chloe Allison is an Application Engineer at OnScale. She received her MA in Electrical and Electronics Engineering from the University of Strathclyde. As part of our engineering team Chloe assists with developing applications, improving our existing software and providing technical support to our customers.