If you are a child of the 80’s like me you probably remember the classic movie the Karate Kid…  and I don’t mean the sequels, reboots, remakes, or any of the other stuff… I’m talking the original one. It was the story of using determination and heart to accomplish your goals and come out on top. It also gave us one of the most quoted dialog ever:

Miyagi: First, wash all car. Then wax. Wax on…
Daniel: Hey, why do I have to…?
Miyagi: Ah ah! Remember deal! No questions!
Daniel: Yeah, but…
Miyagi: Hai!
[makes circular gestures with each hand]
Miyagi: Wax on, right hand. Wax off, left hand. Wax on, wax off. Breathe in through nose, out the mouth. Wax on, wax off. Don’t forget to breathe, very important.
[walks away, still making circular motions with hands]
Miyagi: Wax on, wax off. Wax on, wax off.

As we continue the deep dive into Inventor Sheet Metal let’s explore Inventor’s own Karate Kid… Unfold and Refold!

Using Unfold you can unfold portions (or all) of your sheet metal model to reveal the flat pattern, and unlike when working on the flat pattern, changes you make will be applied to the model when you Refold the unfolded bends. This means you can construct the model with whichever tools you want, without needing to be concerned about how to incorporate pre-bending features into the model

Inventor SM - Unfold Dialog

With Unfold, you start by selecting a Stationary Reference… aka the face that doesn’t move. All selected bends will unfold relative to this selection. In the above picture, I select the longer horizontal face as the stationary reference. Next you select the bends to unfold. Unconsumed sketches do not automatically unfold with the bends, but they can be selected with the Copy Sketches (C) option.

Inventor SM - Unfold Dialog 1

With the bends unfolded, add features as you normally would as now you are basically working with the flat pattern

Inventor SM - Unfold Add Features

You now have two options to Refold; Refold or Refold Feature. The Refold opetion works exactly the same as Unfold, except you can only select bends previously unfolded

Inventor SM - Refold Dialog

The second option, which is the most efficient when you want to refold all the unfolded bends, is the Refold Feature option. To do this locate the Unfold feature in the browser, right-click it, and from the menu select Refold Feature…. and voila! The model is back to its folded state

Inventor SM - Refold Feature


As you can see from the example you can create some very crazy results. However, Inventor is applying the proper corrections meaning everything is theoretically correct!

Now, there is one thing that I get asked a lot about Unfold that, unfortunately, is not achievable out-of-the-box. There is no way to stage the model to create drawing views of the various bends unfolded and then folded. It would be great if we could use Level of Details at the part level to manage feature suppression. We’d then be able to suppress the unfolds / refolds to create various drawing views, showing the order of operations for manufacturing the component.

Thanks and a big fist pump go to Adrian S for sharing a great trick on generating stages within the model. The trick… use iParts!

Inventor SM - iPart with Unfolds

By creating an iPart, you can generate multiple versions, managing the suppression of the unfold features. Using a iPart version per drawing view, you can show the desired order of applying the bends

Inventor SM - Staged SM Drawing with iPart


Feature Image Karate Summer Camp by Flavio