How to Scale a 3D Printed Helmet or Mask (8 Steps)

Scaling is essential for a perfect fit if you want to make custom-fit helmets or masks for cosplay, Halloween, or fun. That is why I wrote this step-by-step guide to walk you through scaling 3D-printed helmets or masks.

To scale a 3D printed helmet or mask, download its 3D model and Cosplay Calipers from Thingiverse. Print the Cosplay Calipers and use them to get your head measurements. Next, download a Sizing Head model, resize it to your head dimensions in Cura, and then use it to scale your helmet model to fit you.

This is an overview of how to scale 3D printed helmets or masks. I will get into details in the article, so keep reading to find out more.

How to Scale a 3D Printed Helmet or Mask

Below is the step-by-step process that you need to follow to scale 3D printed helmets:

Download a helmet or mask model from Thingiverse
Combine your helmet files in Meshmixer and download the file
Get your head measurements
Download the appropriate Sizing Head file from Thingiverse
Load your sizing head model into Cura
Scale your Sizing Head to match your head size if necessary
Import the combined helmet model into Cura and scale it up or down so it fits your sizing head
Slice and print

1. Download a Helmet or Mask Model

Before scaling a 3D printer helmet or mask, download its 3D model from Thingiverse. There are many other platforms where you can also download 3D models for free, such as Cults 3D and MyMiniFactory.

However, most 3D printing users recommend Thingiverse. Here is how you can download your model from there:

Go to Thingiverse and search for the 3D model of the helmet or mask you’d like to download. In this case, I searched for “Killmonger Helmet” and clicked on one of the models.

How to Scale 3D Printed Helmets or Masks - Killmonger Helmet - 3D Printerly

I scrolled down the download page, clicked on “files”, and clicked the download icons to download the front and back portions of the Killmonger Helmet in STL format

How to Scale 3D Printed Helmets or Masks - Killmonger Helmet - 3D Printerly

Alternatively, you can click the “Download all files” button to avoid downloading the files separately.

I chose a folder to store them on my computer and clicked “save”.

2. Combine Your Helmet Files in Meshmixer and Download the File

Sometimes, a model designer may decide to split the files into bits to make them easier to print and wear. You’ll need to combine these files in a program like Meshmixer to fit perfectly.

For example, the Killmonger helmet I downloaded earlier was split into two files: one for the front design and another for the back. This will also enable you to remove the back and wear the helmet.

To combine your helmet files, open Meshmixer, click the “Import” button, choose the first “Killmonger Helmet” file, and click “open”.

Your Killmonger helmet 3D model will be loaded onto your workplane.

Import the second STL file: “Killmonger back”, into Meshmixer. Meshmixer will inquire whether to append or replace the model. Choose “append”, select the file from where you stored it, and click “open”.

Press the shift button and select the two “Killmonger helmet files in the Object browser. After, click “Edit” and select “Combine”.

Once the two files have been combined, click the “Export” button, give the file a new name, and save it in STL format in a folder on your computer.

3. Get Your Head Measurements

After downloading your helmet or mask model, get your head measurements to determine how much you’ll need to scale your model to achieve a custom fit.

To get the circumference, you can do this the old-fashioned way by wrapping a tape measure around your head just above the eyebrows and ears. Note down this measurement, as it will be crucial for scaling.

The second way is by using Uncle Jessy’s Cosplay Calipers.

Go to Thingiverse, search for “Cosplay Calipers”, and pick Uncle Jessy’s 3D model. The other cosplay calipers will also do the trick.

From the download page, go to “Files”.

Download all the STL files for the Cosplay Calipers model by clicking each download button beside them and then print them.

Go to “Thing details” for a summary of the design and some print settings you can use.

Once you’re done printing the various parts of the calipers, assemble them and use them to get your head measurement and note it down.

You can do it as shown in the video below.

4. Download the Appropriate Sizing Head File From Thingiverse

To ensure your helmet or mask fits you perfectly, search Thingiverse for a Sizing Head model. These models are designed to match average head sizes and will serve as a reference for scaling your helmet or mask.

Let’s assume you measured the circumference of your head and found it to be 22 inches.

Go to Thingiverse, search for “Sizing Heads”, and click on the first result.

Select “Thing Details” to get a summary of the different head sizes available that can help you scale your model.

Four head sizes are available, so choose one that closely matches your head measurements. In this case, I selected “Head 2” since it has a circumference of 22.4 inches, closely matching the 22 inches measured.

Head over to “Files”, download the STL file for the “Head 2” model, and save it on your computer.

5. Load Your Sizing Head Model into Cura

Next, open Cura, go to File > Open File > Choose the Sizing Head file from where you stored it, and click “open”. Alternatively, click the Import button, choose your file from where you kept it, and click “Open.

The Sizing Head model will be loaded onto your workplane.

6. Scale Your Sizing Head to Match Your Head Size

A very important step that you shouldn’t forget is to scale your Sizing Head to match your head size as you measured it using the cosplay calipers or tape measure.

If you measured your head size and found it to be 22 inches (as I mentioned before) and the Head 2 Sizing Head’s default size is 22.4 inches.

You’ll need to scale down the Sizing Head model to 98.214% of its original size [(22/22.4) x 100] for it to depict your head size accurately.

To do this in Cura, click the “Scale” icon and tick the “Uniform Scaling” box. After that, adjust the scaling percentage to “98.214” and click enter.

The size of your Sizing Head model will now match the size of your head as you measured it.

Check out this video to learn how you scale your Sizing Head to match your head size.

7. Import the Combined Helmet Model Into Cura and Scale it Up or Down so it Fits Your Sizing Head

Bring the newly combined file into Cura and scale it up or down to fit perfectly on your Sizing Head model. To do this, click the “Import” button and select your “Killmonger Combined file”.

Once the model has been imported into Cura, align it and position it to cover your Sizing Head model. You can do this by clicking the “Move” Icon and adjusting the “x” parameter to “0”. But first, ensure that you uncheck the “Drop Down Model” box.

Now, click on the helmet model to see the resizing handles. Drag the blue handle to make the model taller or shorter, the green one to make it longer or shorter, and the red one to make it wider or narrower.

Carefully adjust the size of the helmet to match the dimensions of your scaled Sizing Head model. Adjust to the perfect fit.

8. Slice and Print

There you have it; you’ve scaled your 3D printed helmet to the size you want. All that remains is slicing the file, saving it in G-Code format, and printing it out.

So, you can select the “Head 2” model and delete it by hitting the delete button, then slice your Helmet model.