Fixing Unstiched Models in Fusion 360

The Source (Literally) of the Problem

When designing 3D models for 3D printing, laser cutting, CNC work, or almost any other purposes, there are a number of great resources for downloading models of common parts other people made. For example, McMaster Carr provides 3D models for almost every part in their inventory, which includes about every nut, bolt, screw, bearing, or other piece of hardware imaginable. GrabCad has a vast library of more sophisticated parts and assemblies, like PCBs, servos, steppers, and many, many other models.

However, sometimes when you download models from these resources, depending upon how Fusion 360 reads the file format you downloaded, there can be issues with the model. Often the models will show up as unstitched surfaces; in Fusion 360, unstitched surfaces show up in a pale yellow color.

Unstiched models show up in a yellow color in Fusion 360

Unstitched bodies are basically just surfaces with no thickness or physical form in the real world. Unstitched bodies in your models can be an issue because they do not convert to files for 3D printing very well, nor do they work in assemblies very smoothly. It is also quite difficult to edit unstitched models in the same way you would other models in Fusion 360.

This quick guide will show you how to convert unstitched surfaces to solid bodies so you can work with them much more easily.

Convert Unstitched Surfaces to Solid Bodies

1. Load your downloaded model into Fusion 360.

First of all you will need to import the model you are working with into Fusion 360. If you have never done this, it is incredibly simple. In the data panel, the section on the left side of the screen that displays your saved file, at the top of the screen, there is a cloud-shaped icon. To upload a model, simply click this icon and browse to your model.

Upload models using the Upload button

2. In the upper-left corner of the screen select the Patch workspace from the drop down menu.

Fusion 360 uses the concept of workspaces to change the selection of tools available depending upon what kind of work you are trying to do with your model. The tools we need to fix our unstitched model can be found in the Patch workspace.

Switch to the Patch Workspace

3. Select the Stitch Tool.

The tool we will use to fix the unstitched model is, perhaps unsurprisingly, the Stitch tool. In the Patch workspace, click the dropdown menu under the Modify section and select the Stitch tool. Just like with all other tools in Fusion 360, this will open a dialog box for using the tool.

Select the Stitch tool under the Modify section.

4. Select the Entire Model.

We want to create a single body from the selection of unstitched surfaces we currently have open in Fusion 360. Therefore, with the Stitch tool open, drag a selection rectangle around the entire part. This should select every surface on the part. However, just to make sure nothing was missed, orbit around the part a bit to make sure there are no yellow unstitched surface missed by the selection box.

Select the entire part using the Stitch tool

5. Click OK to Stitch the model.

With the entire model with all of its unstitched surfaces selected, click the OK button in the Stitch tool dialog box. This will unite all the unstitched surfaces and create a solid part that you can more easily use.

Click the OK button to stitch the model together