How to Create Interlocking Shapes in Sketchup

Featured image_How to Create Interlocking Shapes in Sketchup

In this tutorial we’ll be showing you how to create interlocking shapes in Sketchup! Modeling these types of shapes can be useful for detailed things like joinery and furniture or larger items like domes and archways. For this example, we are going to show you how to create two arcs and interlock them in the center point. First, you’ll have to create each arc. Then, you will add notches to each arc so that they can interlock. Let’s get started!

Begin Modeling Interlocking Shapes

Draw a rectangle. Hit “R” to open the rectangle tool. Draw a rectangle on the blue axis.

draw rectangle of interlocking shapes

Draw Circle. Hit “C” to open the circle tool. The default number of sides is 24. You may want to increase that number to get a smoother-looking circle. Draw a circle using the top left corner of the rectangle as the center point and the top right corner as the endpoint.

draw circle of interlocking shapes

Draw Line. Use the line tool to draw a vertical line from the center of the circle to the top of the circle.

Erase. Use the eraser tool to erase any excess lines from around the arc shape.

erase extra lines to create interlocking shapes

Offset. Select the offset tool. Click on your arch and drag the mouse inward to offset the shape.

offset interlocking shapes

Complete the Curve. Draw a line straight down from the bottom right corner of the offset shape. Use the eraser tool to delete the straight lines of the offset shape.

erase excess curve for interlocking shapes

Select the inner arch. Hold “ctrl” while using the move tool to make a copy. Place the copied arch so that it intersects near the top of the inner arch. Select the copied arch. Hit “Q” to open the rotate tool. Hold “ctrl” again to make a copy and rotate the new copy so that it aligns with the original curve.

complete curve of interlocking shapes

Delete any extra lines until you have half of the arc.

half arc of interlocking shapes

Copy. Hit “M” to open the move tool. Hold “ctrl” to make a copy and move the copy over to the side. Right-click on the copy. Select “flip along” > “green axis.” Move the arch so that the top corners of each half meet.

first half of interlocking shapes

Draw Notch for Interlocking Shapes

The next step is to create the notch that will join both pieces together. To do this, draw a vertical line down the center of the arc. Find the midpoint. Draw a horizontal line that extends 1” past the center line on each side.

Draw Line. Draw a vertical line extending past the arc on each endpoint of the 2” line you just drew.

draw notch for interlocking shapes

Erase. Use the eraser tool to erase the lines that extend past the arc.

Make Group. Select all pieces of the arc. Right-click and select “make group.”

Make Copy. Copy and paste the shape over to the side. Double-click on the arc copy so that you are within the group. Extend the vertical lines of the notch down and erase the top lines. Now you have a notch facing downwards.

draw second notch for interlocking shapes

Push/Pull. Use the “push/pull” tool to extrude each arc back 2 inches.

extrude interlocking shapes

Rotate. Hit “Q” to open the rotate tool. Click on the inner corner of the notch on one of the arcs and rotate the arc 90 degrees.

Move. Select the arc that you rotated and move it so that both notches interlock with each other.

final interlocking shapes

That’s it! Have you ever created interlocking shapes in Sketchup before? Tell us about it below! If you found this tutorial helpful, be sure to check out all of our tutorials for even more tips and tricks.

Happy Hacking!


  1. allstarcarpetandtiles June 24, 2019 at 10:31 am #

    Great tips. I’m bookmarking this page. Its a great resource to keep. Thanks for sharing.

  2. hamzakhan17826 May 19, 2019 at 7:16 am #

    Ok sure, I will follow your steps before going to do exams. I hope your article will help me more.

  3. karlmistos May 14, 2019 at 10:41 pm #

    Thanks for sharing this. I’ll definitely share this with my classmates at de la salle zobel.

  4. classboat01 October 17, 2018 at 7:37 am #

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  5. mikemoreno September 5, 2018 at 3:48 am #

    thank you very much, verry helpfull…

  6. jogesh12345 August 14, 2018 at 1:55 am #

    Very effective and informative article.Thanks for sharing such an important tutorial.

  7. FLMIMA August 11, 2018 at 9:20 pm #

    Really helpful website

  8. Rumi July 15, 2018 at 7:16 am #

    I feel very grateful that I read this. It is very helpful and very informative and I really learned a lot from it.

  9. RJennings April 28, 2018 at 6:12 pm #

    Thank you for this website. The practice questions are helpful.

  10. Scott March 22, 2018 at 1:50 pm #

    Taking this test on Saturday. Last 4.0 exam to complete for the trio, then on to 5.0. This site is my go-to place when organizing what materials I’ll be studying

  11. shozab January 30, 2018 at 2:22 pm #

    Hi , very good article.

    thanks for sharing, keep up the good work

  12. dyba January 27, 2018 at 1:08 am #

    Good advice. Best of luck to all!

  13. KendraShirley January 16, 2018 at 4:04 pm #

    This is my favorite site for practicing for my tests! Great advise and super helpful.

  14. reximagetrim January 16, 2018 at 10:37 am #

    Nice post to read. A complete guide that can help all of us.

  15. tylerstockholm December 17, 2017 at 9:37 pm #

    Nice one… very helpful! Thanks!!!

  16. Aartiwalvekar November 21, 2017 at 8:56 am #

    Nice post

  17. Aartiwalvekar October 9, 2017 at 9:45 pm #

    Great post!

  18. Tony August 30, 2017 at 7:07 am #

    In the NCARB ARE 5.0 handbook they reference Fundamentals of Building Construction: Materials and Methods in both of their example questions for cost estimating. Unfortunately there isn’t a specific chapter on cost estimating, it’s woven throughout the content.

  19. Spencer August 30, 2017 at 1:15 am #

    What is the best reference for cost estimating for PDD.

  20. Amy July 26, 2017 at 3:24 pm #

    Thanks! Great advice

  21. Tony June 29, 2017 at 7:23 am #

    Deciduous trees should only be used for shade (especially in temperate climates). Deciduous trees lose their leaves in the fall and will have little protection against wind in the winter when it is most needed. Likewise, the leafless trees allow solar heat gain in the winter when it is desired, and shade in the summer.

    Coniferous trees are only to be used to block wind and views. Since they don’t lose their needles, they work great for these two items year-round.

  22. Shahid Logan June 28, 2017 at 4:50 pm #

    Hello. My name is Shahid. This comment is for anyone who would like to reply. On the Siteplanning test. To block the wind, can you use a Deciduous tree or must you use a Coniferous tree?

  23. Mike January 4, 2017 at 11:04 am #

    Hi Tony,

    I need to take 5.0 PPD & PDD. Do you plan on posting notes such as “Caroline’s Notes” that you had posted for the various 4.0 exams for either of those sections? I found those notes to be some of the best resources in studying for the 4.0 sections. If so any idea when? Thanks

  24. Stephen October 17, 2016 at 9:30 pm #

    Hi Tony,
    Any updates on the SS exam ? If there’s an expected release date ? Thanks

  25. DesignerHacks October 4, 2016 at 12:11 pm #


    We are releasing practice exams for the SS exam later this fall.


  26. Paige October 4, 2016 at 11:34 am #

    Will you have SS questions on here at some point?

  27. Daniel September 9, 2016 at 8:47 am #

    Great post, very helpful with the lists of suggested materials, I just passed CDs in July and am taking PPP in November so I definitely needed the list.

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