Programmable finger joints in Onshape CAD

Continuing the discussion from Adjusting for Kerf in your Design Parametrically - Fusion 360:

This is a copy of info posted in the thread linked to above. The objective is to show how finger joint tabs and slots can be programmatically inserted into adjacent walls of a box designed with Onshape. The walls are created using standard Onshape features, positioned so that they overlap each other along one edge, and then an Onshape FeatureScript (called Laser Joint) is invoked to create the tabs and slots. FeatureScripts are user programmed macro-like utilities that can be included in any Onshape design to provide features that are not currently available in the official program. They can be written by Onshape employees or any user and are provided in either free or fee-based form.

What follows is the final few steps of the process that creates the tabs and slots. Walls have already been created and positioned so that they are perpendicular to each other and overlapped on each other and the Laser Joint Featurescript. The walls must be aligned so that their ends over lap each other and then the Laser Joint FeatureScript (created by one of the Onshape users) is invoked, and a series of entries are filled out in the subsequent dialog box to create the tabs and slots. The Laser Joint author has provided options for fit, and undercutting (so-called keyholes), among other features.

The walls before the FeatureScript is invoked:

A closeup showing that the walls are overlapped:

The Laser Joint FeatureScript has been invoked and its dialog box displayed for input:

Result with dialog box filled out. I elected for a 1/16" overcut, which creates the clearance hole for the corners and for a perfect fit with no slop. Note that Part 1 in dialog box is one wall and Part 2 is the other wall.

The final result:

A close up of the top corner showing the overcuts in each joint:

After the joints are formed by the FeatureScript you can select one of the wall faces, right click on it, and select “Export as DWG/DXF” from the drop down to save a DXF outline of the wall selected for cutting with your Glowforge.:

I don’t have my Glowforge yet so can actually try cutting a wall so I imported the resulting DXF into Visio just to verify that it looked OK. Until GF supports importing DXFs it will also be necessary to use a 3rd party utility or program to convert the DXF to the SVG file format that Glowforge understands.

One could, of course, repeat the process for all six walls on an enclosed box. Doing the above actually took only a couple of minutes so it is really a quick process, much quicker than it takes to read.

Onshape is a 3D parametric CAD program that (like Glowforge) runs in the cloud on my most browsers, including those in Windows, MacOS, Linux, Android phones, tablets, and Chromebooks, and Ipads and Iphones. It has a free, fully functional version that can be found here:

and they have a number of YouTube tutorials here:

as well as a very active user forum.


No, my bad…i told you wrong. I thought there was a way to copy the content over…We need to ask @smcgathyfay how she did it…

Stephanieeeeee… help!

(At least I was able to tag it with Tutorial, so we can add it to the section that gets set up eventually.)

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I tried copying over the content of the post, but the image HTML was translated to text. If I get some time today I’ll manually update the OP in this thread.

Thanks for adding the tutorial tag; I had trouble with that too. Must be getting old - this sort of thing used to be easy for me.

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On your original post - click the little dots next to Reply, then on the Wrench and make your original post a Wiki. (It keeps it open for editing longer, otherwise it will lock you out in a week.)

(I’m still learning all the ins and outs too.) :neutral_face:


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I edited the 1st post to incorporate the text and images from the linked thread and some small editting changes.

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It looks great Mike! (And it should cause a lot of newbies to choose Onshape, 'cause that scripting feature looks pretty powerful.)

Thanks for putting it all together!


Very nice tutorial, thanks for taking the time!


Just logged into my Onshape account today to see they’re changing their plans! No more free private documents :cry: (used to be able to have 10 private documents with limited space). Now they have it being unlimited public documents with unlimited public space. Guess I’ll have to switch over to Fusion360…little hesitant as it couldn’t even install without errors on my computer, but it looks like from other users it’s manageable. I do love my SolidWorks though at work!


Yep, and they have been getting a fair amount of flack from the maker/hobbyist users over it, especially since this is the 2nd major change in free plan policy in the past 6 months or so. I have a couple of private documents in Onshape that need to stay private for ethical reasons so I will now have to reproduce that work in another CAD product and migrate over dumb solids of the parts before the change goes into effect on December 15. I’m keeping my account in Onshape for non-proprietary projects, mostly ones that will be lasered, because it looks like some of their unique tools have value there. For other new work, I’m giving Fusion 360 a serious tryout and may move over to that.

This change in Onshape policy also is a reminder that cloud computing has some drawbacks. In pretty much any other CAD program that runs from my local disk I only need to keep copies of the install files and my part files on the local disk in order to revise the designs, create new drawings, or generate dumb solids for CNC work. Once the Onshape policy takes effect though, I will no longer be able to do those things with the private files. Since Glowforge is strictly cloud-based, users could face similar sorts of limitations with their laser cutter. Such GF problems could result from changes in policy, sale of the company assets, or simply GF shutting down. I know that GF has hinted that there will be a way to deal with those issues should they arise, but 8 months ago I was confident of ongoing access to my private documents in Onshape and that is now about to disappear, so the pragmatic side of me acknowledges cloud access to the GF as presently envisioned is not a guaranteed thing and there may be nothing Dan can do about that.