Top Ten Tips: Designing Models For 3D Printing

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Kacie Hultgren, aka PrettySmallThings, is a Broadway scenic designer who uses her 3D printer to build scale models for set designs, among other amazing things, like her 3D printed “Clutch Purse” and “Zip Top Bag.” She was also a member of the 2014 Ultimate Guide to 3D Printing testing team.

Zip Top Bag from SmallPrettyThings

You can learn more about Kacie from the 5, 4, 3, 2, 1 About Kacie Hultgren maker profile we posted in June.

Kacie’s Top Tips

45 Degree Rule

Remember 45 degree rule, overhangs that are greater than 45 degrees will need support material or you need to use clever modeling tricks to get the model to print. Create your own support / bridging objects (cones and other supports) by designing them into your model.

Design To Avoid Using Support Material

Although support algorithms are improving all the time, support material can leave ugly marks on the outside of your prints. Support material can also be time consuming to remove. Design your models so that they are 3D printable without support.

Windsor Chairs by SmallPrettyThings

Add Custom Supports

Use “mouse ears”, helper disks and cones designed into your model to help it print without the use of computer generated supports.  Tony Buser’s “Mouse Eared Rocket Fincan” and PrettySmallThings “Windsor Chairs” are excellent example of this design technique. Ditch the raft, it really slows down your prints. Depending on your software / printer configuration rafts can be difficult to remove and also mar the bottom of your prints.

WHPThomas’ PLA Pin Connectors, derived from Tony Buser’s original ABS set.

Know Your Printer’s Limitations

Know your model details. Are there tiny towers and small features that are too small to be printed in plastic on a desktop 3D printer? An important, but often overlooked, variable in what your printer can achieve is thread width.

Thread width is determined by the diameter of your printer’s nozzle. Most printers have a 0.4mm or 0.5mm nozzle. Practically, this means that a circle drawn by a 3D printer is always two thread widths deep: 0.8mm thick with a 0.4mm nozzle to 1mm thick for a 0.5mm nozzle. As Kacie states in the video, the rule of thumb is “The smallest feature you can create is double the thread width.”

Fit Tolerances for Interlocking Parts

For objects with multiple interlocking parts, design in your fit tolerance. Getting tolerances correct can be difficult. Kacie’s tips for creating correct tolerances:  use a 0.2mm offset for tight fit (press fit parts, connecters) and use a 0.4mm offset for lose fit (hinges, box lids). You will have to test it yourself with your particular model to determine what is the right tolerance for the thing you are creating.

Stretchlet by Emmett

Use Shells Properly

Don’t use additional shells on fine featured models, like small text. It will obscure the detail.

Optimize for Thread Width

Use thread width to your advantage. If you are making flexible models or need very thin features, design the walls of your model to be one thread width thick. Check out Hultgren’s collection of “Flexible Inspiration” model collection on Thingiverse for more examples on utilizing this technique.

Orient for the Best Resolution

Always orient your model for the best resolution possible for that particular model.  Models can be sliced into pieces if necessary and then re-assembled. On Fused-Filament Fabrication printers, you can only control the Z resolution. The X and Y resolutions are determined by thread width. If your model has fine features, make sure the model orientation is cable of printing those features.

SmallPrettyThings sliced Plated Okapi derived from Okapi by Masayuki

Orient for Stress

To keep prints from breaking when force is applied; make sure to orient your model to minimize stress on the part by orienting the model so that the print lines are perpendicular to point of the pressure being applied.

The same principle applies to ABS, which when used to print large models, can split along the Z-axis as they cool on the build platform during printing.

Clutch Purse by SmallPrettyThings

The “Holy Grail”: Print and Place Designs

Print in place designs that contain multiple integrated parts, are the “Holy Grail” of FFF desktop machines. Here are Hultgren’s tips on how to tackle “print in place designs”: pull design elements to platform, use bridges for captive parts and gap print carefully.

Watch the video for more details and context. Do you have tips on designing for 3D printing? Share them with us!

7 thoughts on “Top Ten Tips: Designing Models For 3D Printing

  1. samgibson4113 says:

    I’m looking forward to getting a 3D printer. I can’t believe all the cool things you can do with a 3D printer. In the meantime, I’ll just keep using the services of a good digital printer for 2D images.

  2. Mojo says:

    may i know which 3d printer you are using for producing above models?

  3. Nathaniel Petre says:

    A spelling correction “make sure the model orientation is cable of printing those features”.

  4. Yobi3D says:

    Yobi3D is a 3D model search engine. It provides a basic analysis on whether a 3D model is easily printable. Check it out.

  5. Travis Birtt says:

    Brilliant tips and designs by the way. I haven’t thought anything like this. There are some great design mentioned here in this post. I mean I would also like to appreciate the Kacie tips for correct tolerances.

  6. Brian Crotty says:

    One of the main things that you are missing is printing based on Material type. It makes a huge difference in terms of the design, orientation, etc.

    I use to select the material I want to print in to ensure that it will print correctly.

  7. Tiny says:

    Are you looking for a organised place to discuss 3d printing? Check out It is a forum all about 3d printing. It contains help, ideas, tips, tricks, guides, and advice. Come join a great community and learn more about 3d printing.

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Anna Kaziunas France is interested practical digital fabrication focused project documentation (anything that turns codes into things), as well as adventures in synthetic biology, biohacking, personal genomics and programmable materials.

She's currently working on the forthcoming book "Design for CNC: Practical Joinery Techniques, Projects, and Tips for CNC-routed Furniture".

She’s also the Academic Dean of the global Fab Academy program, the co-author of Getting Started with MakerBot and compiled the Make: 3D Printing book.

Formerly, she worked as an editor for Make: Books, was digital fabrication editor and skill builder section editor for Make: Magazine, and directed Make:'s 2015 and 2014 3D Printer Shootout testing events.

She likes things that are computer-controlled, parametric, and open— preferably all three.

Find her on her personal site, Twitter and Facebook.

View more articles by Anna Kaziunas France


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