Unwrap and Flatten Faces Extension

Unwraps faces and lays arbitrarily oriented faces flat on the ground.

Flattening a shell in segments
Flattening a shell in segments


flatten-icon-512This extension allows the user to do two things:

  • Unwrap non-coplanar faces using an automatic (random) algorithm and then lay the resulting set of faces flat on the ground.
  • Lay any arbitrarily-oriented face or collection of coplanar faces flat on the ground. Use e.g. in combination with a manual unfold tool or to make sure faces are perfectly horizontal.

This extension is useful for e.g. producing fabric or sheet-metal templates, laser-cutting templates, as CNC-prep, for texturing, etc.


Select one or more connected faces in your model and right-click on them to get the “Flatten Faces” context menu. All selected faces will be grouped in this process. See the video below for examples. Please note that the faces must not be grouped.

Also keep in mind that the unwrapping algorithm doesn’t always work automatically. It basically starts at a random face and tries to line up all faces in a logical pattern (a “string” of faces if you will). If this doesn’t succeed, then it tries 100 times to get this right. If it still doesn’t work (you get an error or the results don’t look right), re-try with fewer faces in your selection and stitch them manually. Each run is random, so results can vary between tries.

Screenshots and Videos

Selecting multiple faces
Selecting multiple faces
Command in context menu
Command in context menu
Result of flattening
Result of flattening a single face


You can now find this plugin in Trimble’s Extension Warehouse. For an easy install (and update notifications), browse to it from inside SketchUp (2013 or newer) and install it directly.

Alternative Downloads

Download “Flatten Faces Plugin (RBZ)” as_flatten_2-1.rbz – Downloaded 4190 times – 4 KB

Download “Flatten Faces Plugin (ZIP)” as_flatten_2-1.zip – Downloaded 4319 times – 4 KB

To install these files, follow the SketchUp folks’ instructions. You can also find this plugin on GitHub.

Revision History

  • Version 2.1 (2/22/2015):
    – Added Tools menu item to remove confusion
    – Added statusbar feedback (important for larger models)
    – Added Help submenu item
    – Code cleanup
    – Fixed SU 8 bug with array.count
  • Version 2.0 (1/27/2015):
    – Added functionality to automatically unwrap non-coplanar faces first
  • Version 1.0 (2/12/2014):
    – First release
  • SandBagSix

    SU 2016 is calling this an Unidentified Extension which I find it hard to believe since it came from the Extension Warehouse. It also said it needed access to the computer’s file system, am I missing something?

    • Hmmm, odd. You can set the security requirements in the preferences to allow all extensions, which should get rid of issue #1. #2 doesn’t make sense for this extension. I need to upload an update soon anyways, so maybe that’ll fix that.

  • JasonR704

    Hello Alexander, I have downloaded your extension and tried to flatten out this curved design, but I’m having a very difficult time. I’d be happy to pay for your help!

    The use case for this design is that of a miniaturized hot air balloon. I will need to flatten this design and then cut a pattern which will be used to create many identical pieces of fabric that will then be sewn together.

    Very curious to know how to do this! Thank you in advance for any assistance you can lend.

    • In principle what you have here is a double-curved surface, which as such can’t be flattened without distortion. You can select vertical or horizontal “strips” of faces and then flatten those with my extension. That will give you cut patterns for fabric that you can stitch together. However, it assumes that you are not using flexible material that can actually stretch. Therefore such an approach is best when using sheet metal or heavy-material (e.g. if this were a full-size hot-air balloon. Because you are just making a smaller balloon, try flattening it in strips and then make an educated guess as to the outline that you are getting. when you cut that and stitch it back together, then you should be close enough.

      • JasonR704

        I’ll give that a try and see how it turns out. Thanks so much for responding back, really appreciate an expert willing to help us out!

  • Gennaro Langella

    Thank you very much!

    It helped me A LOT!

  • Thomas Asmuth (kidNeutrino)

    This looks very cool, thank you for sharing. I have 2015 Pro and it isn’t allowing me to select complex objects. Any suggestions? Did I miss a step?

    • Thomas Asmuth (kidNeutrino)

      Restart of the program got it working correctly. :) Thanks again.

  • ijpelaar

    I have tryed it for a horn flare, but it is 2,2244603 cm to short when flatten. I need two digid precision here. so 2,22 rest is not important.

    Maybe I do something wrong, do work fine for the rest,..


    • Can you upload an image in a comment that shows this? Not sure why it shouldn’t be exact.

      • ijpelaar

        I do put it on photobucket tonight. the lengt is in bend form 60,9 cm and flatten 58,7 cm I do also not now why, a other bend program did different, I can also send the sketchup design itself so you can test it.

  • Albert

    ad. previous comment was based on the 2013-version of Sketchup, now I updated Sketchup and the plugin works fine. Thank you for the plugin, I think it is very useful.

  • Albert

    On my computer it only works with one face. If I choose more than one face the plugin doesn’t do anything.

    • Thomas Asmuth (kidNeutrino)

      I have the same issue; could it be it isn’t playing nice with 2015?