SolidWorks Defeature: How to Increase the Performance of Imported Parts

One tool that I think gets overlooked for it abilities is the Defeature tool, which was introduced in SolidWorks 2011 and has the ability to remove details from part or assembly files.

Where I find this tool especially useful is on parts that I download from customers or websites like 3D ContentCentral because many time files come in as assemblies with multiple levels of sub-assemblies and components with either too many features to figure out what needs to be suppressed or deleted. Removing these details not only takes a complex assembly and brings it down to a single part it can also give us significant performance gains.

For the example I use in this article I am using a motor assembly that I downloaded from 3D ContentCentral.

Lets first take a look at the assembly and parts that were downloaded for the assembly.

The main body contains 81 features and has a 2.1 second rebuild time. 

Body-Stats

Our Assembly has 4 parts, 5 bodies, and 12 mates.

Assy-StatsAssy-Rebuild-Times

Next we will walk through the basic process of an Assembly Defeature.

Step 1: Components

From the Tools drop-down select Defeature and in Step 1 you have the ability to remove Internal components, Small or Selected components. There are is a live section tool available so you can look at different cross sections throughout the Defeature process.

For our somewhat simple assembly Step 1 does not remove any detail.

Defeature-Step1

Step 2: Motion

If you want to allow motion in an assembly, you can remove details from groups of components and allow motion between the groups.

For this example we will skip this step.

Defeature-Step2

Step 3: To Keep (or not to Keep)

This step fills in any open voids in the files so you will want to select the internal faces of any items you want to keep such as mounting holes. There are also filters for selecting all holes or holes within a specified size range.

We kept out four mounting holes.

Defeature-Step3

After selecting Next, SolidWorks will go to a split screen with a preview on the right so you can see what features have already been removed. The preview part also zooms and rotates with the original assembly.

Defeature-Step3-Next

Step 4: To Remove

This allows us to select items that were not automatically removed. When you select an item you get the pop-up that allows you select the face, feature, body or part. When you select an item it takes all the related items and adds them in to the Items to Remove box where you can go thru and remove any features you do not want to have removed.

Defeature-Step4
Once you select next it will update your preview window.

Defeature-Step4-Next

Final Step: Feature Removal Complete

If you are happy with the end result you can then finish out by Saving the model as a separate file, Publishing it to 3D ContentCentral or Storing the settings for future use.

Defeature-Final-Step
Defeatured-Part

So just to bring it all to a conclusion, I saved my file out as a separate part file and my new file opens as a single solid body with a rebuild time of 0.00 seconds. Comparing our two file sets to each other here is what we have and I hope everyone can see the benefits of having a single part vs. a multi part assembly.

Original Assembly:

  • 1-Assembly with 4 Part files, total size of all files 2759KB
  • Total Part Features – 152 (Body 81, Shaft 23, Power Conn. 24, Encoder Conn. 24)
  • Total SolidBodies – 5
  • Rebuild Time 0.081s (81ms per AssyemblyXpert)
  • Mates – 12

Defeatured Part:

  • 1-Part file, total file size of 2566KB
  • Total Feature(s) – 1
  • Total Solid Bodies – 1
  • Rebuild Time 0.00s (assume 0.0 to 4.4ms)
  • Mates – 0

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Josh Altergott is Support Manager at Computer Aided Technology, a SolidWorks Value Added Reseller with locations in Kentucky, Missouri, Kansas, Indiana, Wisconsin and Illinois. He is a regular contributor to the CATI Tech Notes blog.

Josh Altergott
Josh Altergott is Support Manager at Computer Aided Technology, a SolidWorks Value Added Reseller with locations in Kentucky, Missouri, Kansas, Indiana, Wisconsin and Illinois. He is a regular contributor to the CATI Tech Notes blog. http://blog.cati.com/
  • Travis

    I agree that Solidworks Defeature is a great tool for reducing file size and internal features of parts or assemblies that I do not want to share with customers. The Defeature function works well with simple parts and assemblies (typically just machined parts), but it seems to struggle a lot with complex castings, that have cast geometry openings and irregular surfaces.

    I have used a competitors 3D CAD system over 7 years ago, and their ability to “shrink wrap” parts and assemblies far exceeds the capabilities offered by Solidworks. Defeaturing is not necessarily straightforward and can take many hours to produces acceptable results, as you need to guess and re-guess how the defeatured assembly will behave.

    My suggestion is that Solidworks invests heavily in the Defeature capability, as it is badly lagging its competitor(s).

    I love Solidworks modeling capability, but I need a tool that doesn’t take so much time to produce a “defeatured” part.