Optimizing Downloaded Models in SOLIDWORKS

Most SOLIDWORKS users have worked with downloaded models at one time or another. Some use them every day. Regardless of what you’re using them for, there are best practices you need to know. Optimizing downloaded models is a crucial step to ensure future success with your SOLIDWORKS parts, assemblies, and drawings. Whether you download models from MySolidWorks, McMaster-Carr, or somewhere else, you need to optimize them for performance before using them. First, let’s look at why, and then how.

Optimizing Downloaded Models – A Light Snack or a Heavy Meal?

Think about eating a sandwich. I know, that’s a weird analogy for a CAD blog, but bear with me for a moment. You could have a peanut butter and banana sandwich. Just a smear of peanut butter and a few slices of fresh banana. A simple, light snack popular with many kids here in the South. Or, you could have Elvis Presley’s favorite version of the PB&B. Mix peanut butter with a ripe banana and smear a generous helping between a couple of slices of bread, add some bacon, and grill it in a pan with lots of butter. Love it or hate it, nobody will mistake this for a light snack! The ‘Elvis Sandwich’ sits heavy in your belly.

How does this pertain to SOLIDWORKS, you ask? Just like you have to digest every sandwich you eat, SOLIDWORKS has to digest every model you load into RAM. Not all models are created equal. Some are light snacks, and some are heavy meals.

Optimize Assemblies by Optimizing Parts

Every meal is the sum of its ingredients, and every assembly is the sum of its parts. If you want your assemblies to load faster and lag less, you need them to sit lightly in your RAM. That means optimizing them for your needs. When you use a downloaded model as is, you are blindly trusting whoever created it to have done this for you. But they may not have the same needs you do.

For example, the modeler of a particular socket head cap screw may have prepared it with maximum detail for manufacturing. At the same time, you only want to use it as an assembly component without caring about the intricate details. In other words, you wanted a simple PB&B but got the full Elvis instead!

There are two main factors that contribute to the ‘heaviness’ of a SOLIDWORKS model:

• The Image Quality Setting
• Geometric Complexity

Optimize Image Quality

When you open a SOLIDWORKS part model, there are 3 main things you have access to: feature history, body data, and graphics data. The feature history is not the CAD model itself, but the instructions or ‘recipe’ for how to create it. The body data is the result of following those instructions. It’s the exact geometric definition of the model. Unfortunately for us humans, this is a bunch of ones and zeros we can’t use directly.

What we see on screen is only a graphical mock-up of the body data created using graphics triangles. The more there are, the longer it takes to load the model, and the more lag we are likely to see while working with the model. You can control how large or small the individual triangles are by going to Options>Document Properties>Image Quality.

Image Quality Settings

Moving the slider to the left makes the triangles larger, so you need fewer of them; the file size decreases, performance increases, but the curves will look blocky. Moving the slider to the right will make the triangles smaller, so you need more of them; the file size increases, performance decreases, but the curves will look smoother.

Make sure the slider is as far to the left as you can stand to work with. There’s also an advantage in making sure all the components of your assembly have the exact same Image Quality setting. This helps the assembly process the graphics faster. We cover this topic extensively in our Large Assembly and Drawings Workshop. 

Simplify Geometric Complexity

The more complex the model, the more triangles are needed to represent it. Any flat rectangular face can be represented with just two triangles. More complex faces require more triangles, and curved faces require a lot more. Helical threads, small fillets, and chamfers add a lot of complexity to a model. A lot of small radii result in high curvature, which in turn equals more triangles.

Here is an example of an unmodified socket head cap screw I downloaded. Image Quality and geometric complexity are both very high. Performance Evaluation reveals a Face Count of 370 with 38,236 Graphics Triangles. Each instance of this part in an assembly will multiply its impact.

Unoptimized SOLIDWORKS model

Let’s look at the same model after reducing Image Quality and suppressing features we don’t need in the context of an assembly. Face Count is now 13 with a mere 234 Graphics Triangles.

SOLIDWORKS model after optimization

When working with SOLIDWORKS, it’s a good idea to ask yourself if the tool you’re using is the right one for the job at hand. In the case of downloaded models, the answer is often no. However, with a little knowledge and a few minutes of work, you can tailor them to your exact needs. TriMech’s team of experts is on hand to help you understand your SOLIDWORKS performance and how to extract everything out of your machine. We offer complimentary Client Care Visits to subscription clients to provide additional best practices for your modeling workflow.

If you want more in-depth help to tame your large assemblies, sign up for our workshop here.