An Advanced Breakdown of the SOLIDWORKS Fillet Feature Tool

The Fillet feature is one of the oldest features in SOLIDWORKS software. It was included in the software when the product was first released back in 1995. Most SOLIDWORKS users have created models utilizing the Fillet feature, but many users are unfamiliar with some of the great options available within the Fillet feature. In this two-part series, we will dive a little deeper into some of these great time-saving options.

image001Figure 1. The Fillet command on the Features toolbar.



When first creating a Fillet feature in the software, you will be presented with a toggle button at the top of the property manager labeled “Manual/FilletXpert.”

image002Figure 2. The Manual/FilletXpert toggle.

The FilletXpert is one of the many “Xpert” tools available in the software. These Xpert tools can be used to assist in the creation of features and in troubleshooting potential problem areas in your software models.

image003Figure 3. The various Xpert tools in the SOLIDWORKS software.

For today’s article, we will be focusing on the manual fillet options, and will not be focusing much on the FilletXpert.

One important thing to note about the FilletXpert toggle is that the option for FilletXpert is only available when you are working with models that have one single configuration. If your model has more than one configuration, the option for FilletXpert will not be available.

image004Figure 4. The FilletXpert is not available when working with a part that has multiple configurations.


Fillet Type

After clicking on the Fillet icon on the Features toolbar, you will be presented with a choice of four different fillet types.

image005Figure 5. The four different fillet types.

In today’s article, we will take a look at each of these four fillet types. But before we do that, let’s take a look at two options you will see anytime you create a fillet, regardless of which type of fillet you choose to create: “Tangent propagation” and the “Preview” options.


Preview Options

There are three options for previewing a fillet in the software: “Full preview,” “Partial preview” and “No preview.”

image006Figure 6. The three options for preview. “No preview” is the default option; “Full preview” is recommended.

In the following part example, each of the six edges has been selected to be filleted. Setting the option for preview will yield the results shown in Figure 7.

image007Figure 7. The results of using the software’s preview options.

As is shown in Figure 7, the “No preview” option only highlights the edges that you have selected. The “Partial preview” option highlights all the selected edges and shows a preview of one single fillet. The “Full preview” option shows all the selected edges highlighted and shows a preview of each fillet being created.

The “No preview” option is the default out-of-the box setting, but the “Full preview” option is recommended to ensure that the results of the Fillet feature are predictable and successful. However, if you have a Fillet feature with quite a few edges being filleted (over 50), changing the preview option to “Partial preview” or “No preview” may be recommended to achieve better performance (since you won’t have to wait for a preview of all 50 filleted edges).


Tangent Propagation

The option for “Tangent propagation” is one of the most powerful and useful options included in the Fillet feature.

image008Figure 8. Turning on the option for Tangent propagation.

With this option selected, you can choose to create a single fillet, and any tangent edges or tangent faces that this fillet encounters will automatically become filleted as well. This can be a huge time saver, as it often omits the need to select these additional edges or faces.

Let’s take a look at an example using the “Constant Size Fillet” feature.

image009Figure 9. Example of the “Tangent propagation” option being toggled off (top) and on (bottom).

In Figure 9, you can see the results of toggling “Tangent propagation” on and off. With this option turned off, you can select a single edge and only that edge is filleted. However, when you toggle this option on,you will see that any tangent edge that your original edge encounters is automatically filleted with the same value as the original edge. In this simple example, the result of selecting one single edge is that 12 edges are being filleted. This is a great time saver and should be toggled on by default, although there are some rare occasions where you can get more desirable results by toggling it off.

Both “Tangent propagation” and the fillet preview options are available for all four types of fillets in the software. Next we will take a look at the four different types of fillets in more detail, starting with the “Constant Size Fillet.”


The Constant Size Fillet

The “Constant Size Fillet” is the fillet type most frequently used by most engineers. You simply select the edge to be filleted and a Fillet feature is added to the selected geometry. The term “Constant Size” indicates that the fillet will have the same value throughout the entire duration of the selected edge.

image010Figure 10. The most common fillet type is known as the “Constant Size Fillet.”

Most people are familiar with these basic functions of the Constant Size Fillet, but what else can you do with this command?


Selecting Edges vs. Selecting Faces

When utilizing the “Constant Size Fillet,” you may either select edges or faces to be filleted. When you select a single edge, only this edge has a fillet applied. When you select a single face, all edges that this face is touching will have fillets applied.

image011Figure 11. Selecting a single edge compared to selecting a single face in a “Constant Size Fillet.”

As you can see in Figure 11, when you select a single edge, only that edge gets a fillet applied. But when you select a single face, all edges that are touching that face have fillets applied. This can be a nice shortcut, especially when working with rounded or circular faces.


Multiple Radius Fillet

When working in the “Constant Size Fillet,” you have the ability to select more than one edge or face in a single command. By toggling the option for “Multiple radius fillet,” you can specify a different value for each of these selected edges.

image012Figure 12. Toggling on the option for “Multiple radius fillet” in a “Constant Size Fillet.”

Once you toggle on the option for “Multiple radius fillet,” a callout will appear on each of the edges that are selected to be filleted. In Figure 12, six edges have been selected to be filleted. By toggling on the option for “Multiple radius fillet,” we were able to set two of these fillets to have a radius of 1.25in, two to have a radius of 0.50in and two to have a radius of 0.25in.

This can all be created in a single feature, which is a great way to save some time as well as keep your feature tree nice and tidy.


Asymmetric Fillet Options

In SOLIDWORKS 2015, a new option was added to the “Constant Size Fillet” known as the “Asymmetric” option. This terrific tool allows you to create a fillet by inputting two numbers and generating a non circular profile for the fillet.

image013Figure 13. Using the option for “Asymmetric Fillet” in a “Constant Size Fillet.”

By using the option for “Asymmetric Fillet” shown in Figure 13, we were able to set the profile type to “Elliptic” and set the major radius to 0.5in and the minor radius to 0.25in. Some other profile types that yield similar (but slightly different) results are “Conic Rho” and “Continuous Curvature.”

image014Figure 14. The three profile types available for an “Asymmetric” fillet.

These enhancements to the “Constant Size Fillet” are a huge time saver. In the past, if you wanted to create five different asymmetric fillets, you would have to use five different “Face Fillet” commands. Now you can create all five fillets in a single command, using a “Constant Size Fillet” and a much more intuitive system to input the dimensional values.


Setback Parameters

Sometimes when creating a “Constant Size Fillet,” a situation will occur where the desired result requires three fillets with differing radius values to meet at a single corner.

image015Figure 15. A “Constant Size Fillet” feature with three multiple radius fillets meeting at a single corner.

In Figure 15, you can see that a “Constant Size Fillet” has been created with three edges selected. The option for “Multiple radius fillet” has been toggled on, and each of the three edges has a different radius value. The three fillets meet at a single corner.

You will also notice that the options for “Setback Parameters” have not been enabled. These options are utilized when you have a corner where multiple fillets are coming together and you wish to specify a “blend” into this corner region. By selecting the vertex where the edges meet and then specifying the distance from the corner where you want the blend to begin, you can generate a corner with much more aesthetically pleasing results.

image016Figure 16. Enabling the “Setback Parameters” to smooth out a corner.

After selecting the intersection vertex in the “Setback Parameters” selection box, you will be prompted to input a dimension in each of the three directions of the intersecting edges. By increasing or decreasing this number, you can adjust the distance between the start of the blend and the filleted corner until the desired result is achieved.

image017Figure 17. Final results of smoothing out the corner using “Setback Parameters.”


Fillet Options

At the bottom of the “Constant Size Fillet” property manager, there is a section called “Fillet Options” that contains some final options to consider.

image018Figure 18. The “Fillet Options” section at the bottom of the “Constant Size Fillet” property manager.


Select Through Faces

The first option, “Select through faces,” allows you to pick edges that are hidden behind solid faces of the model. Normally, the model would need to have its display set to “Wireframe” or “Hidden Lines Visible” in order for you to select edges that are obstructed by a face of the model. But when working in the Fillet command with the option for “Select through faces” enabled, you may select these edges right through the model, even when the model is displayed in shaded mode. This is a great time saver, since you do not need to rotate the model in order to select these hidden edges.


Keep Features

The next option, “Keep features,” would only affect a feature that is intersected by a newly created Fillet feature. A common example of this would be a small boss near the edge of a model.

image019Figure 19. The fillet that is fully encompassing a boss feature will yield different results depending on the setting for “Keep Feature.”

In Figure 19, you can see a small circular boss near the edge of the model. The fillet is large enough that it fully encompasses the diameter of the circular boss. With the “Keep features” option enabled, the boss remains in the model. However, if the “Keep features” option is unchecked, the fillet will consume the boss extrude, causing it to disappear.


Round Corners

The “Round corners” option is particularly useful when creating a rectangular boss on the top of the model and choosing the lower edges of this boss to be filleted.

image020Figure 20. A fillet is applied to the four lower edges of the rectangular boss with “Round corners” toggled off and on.


Overflow Type

The final section of options at the bottom of a “Constant Size Fillet” is listed as “Overflow type” with three options: “Default,” “Keep Edge” and “Keep Surface.” The option for “Overflow type” will only come into play when there is not enough room for a fillet to fully resolve due to the surrounding geometry.

image021Figure 21. A fillet that is too large to resolve due to the surrounding geometry.

In Figure 20, you can see a rectangular plate with a circular boss sticking out of the top. The fillet being applied at the base of the circular boss is too large to resolve due to the edges of the rectangular plate. In scenarios like this, the software will give you two options to define the resultant geometry of the fillet.

image022Figure 22. An example of using the options for “Keep edges” and “Keep surface.”

You may choose to “Keep edges,” meaning the rectangular edges of the plate will retain their current position. This will typically result in the fillet being broken up into multiple surfaces and the upper edge of the fillet varying in height.

Your second option would be to choose to “Keep surface.” With this option enabled, the filleted surface will be one continuous surface and the top edge of the fillet will be maintained at a constant height, but the lower original edges of the rectangular plate will become curved to facilitate the creation of the fillet.

There will be occasions where one or the other option will yield the most desirable results.



The Fillet command is one of the oldest and most powerful features in SOLIDWORKS software. Over the years, the Fillet command has had some terrific features added to it, but sometimes these options can be a bit confusing or mysterious. Hopefully, after reading this blog you will have a much better feel for these great features, and you can start using them today. Be sure to check out the next article, where we’ll take a look at the remaining three fillet types.

Happy filleting!

About the Author


Tobias Richard is a SOLIDWORKS elite applications engineer from Philadelphia, Pa. He has been working with SOLIDWORKS software since 1998 and has been providing training, technical support and tips and tricks since 2001.

Recent Articles

Related Stories

Enews Subscribe