SOLIDWORKS tutorials surface design – How to knit two surfaces together into a single continuous surface

SOLIDWORKS tutorials – Surface Design

How to create a single continuous surface using the Knit Surfaces tool in SOLIDWORKS

Hello there, and welcome back. In this SOLIDWORKS tutorial (surface design), I’ll show you how to use  Knit Surface tool. This tool is basic to surface design and modeling. This tutorial is an excerpt from my SOLIDWORKS tutorials Surface Design & Modeling course.

The Knit Surface tool is how you can join and bond two unique surfaces together, so that they share curvature and tangency. It’s not a klunky join; it’s nice and neat, and offers options for knitting any gaps you may have between the surfaces.

Take a look at the model in my graphic area, and then at the Surface Bodies folder in the Feature Manager Design Tree on the left:

SOLIDWORKS tutorials surface design - using the knit surface tool

SOLIDWORKS tutorials surface design – using the knit surface tool

As you see, my model comprises two separate surface: Surface-Plane 1 and Surface-Trim 3. So, if you want to find out at a glance what’s going on in your graphic area, you can check the Solid Bodies and Surface Bodies folders at the top of the tree.

Now, let’s go to the Surfaces tab and activate the Knit Surface command;


It’s actually on the far right of my ribbon, as you see above.

Our first job is to select the surfaces we want to knit together. Check out my screen shot below: first, click in the selection box to activate it for selecting. This is how we select things in SOLIDWORKS. We can make our selection in the graphic area, or from the feature manager design tree. Either way, once the surfaces are selected, they will be listed in the selection box as you see below:

Solidworks tutorials Surface Design - how to knit surfaces

Solidworks tutorials Surface Design – how to knit surfaces

There’s a checkbox called Merge Entities. This is for when your surfaces overlap. If you check this box, SOLIDWORKS will knit and merge your overlapping surfaces. Sweet and easy!

In the lower half of the Knit Surface property manager, there is a section for gap control. This is where SOLIDWORKS will apply its knitting needles to any gaps between your two surfaces. Nice, huh?


Basically it works like this: SOLIDWORKS will fill, automatically, any gaps that are less than 0.1 millimeters. BUT there are a couple conditions: you have to have the box next to Gap Control checked. Secondly, SOLIDWORKS has to find your gap, and list it in this window. Then you have to check it. If you try to click Accept with the box unchecked, the knit algorithm will fail. You’ll get a rebuild error, so make sure any gaps you want filled are checked.

Let’s click the green checkmark to accept our work. And presto, SOLIDWORKS merges the two surfaces into a single continuous surface, as you see below.


This concludes our overview of how to knit surfaces. To watch a video of this tutorial, where I show you another example which includes creating a gap, and troubleshooting the gap control tool, please see this video on my youtube channel,

Mille grazie!

Rosanna D, VTN