We are ALMOST there, I promise!
At this point, we could export our shapes from Inkscape to PDF as a pattern, or into Lightburn for cutting, but there is the matter of the grooves in surface of the helmet. As I have mentioned before, there are a couple ways to handle this. One is subtractive – you remove some of the material to etch the groove into the surface. The other is additive – add more material in a strategic manner to make the grooves. They both have their pros and cons.
Subtractive
Pros:
* In the long run, it will be cheaper. You are removing material from the surface so you don’t have to build it up, thereby saving on materials.
* It can be easier than attempting to fit additional pieces together with precision.
* With the right bits on your rotary tool, you can carve some amazing details – especially with organic details.
Cons:
* Without specialty tools or attachments (like the router fitting for a rotary tool), it can be extremely difficult to make these cuts with precision. This means that it is easy to mess it up. ESPECIALLY with precise geometric shapes (like the grooves in the helmet).
* The material we are working with is amazingly forgiving in some ways. HOWEVER, it is VERY soft and the tools we are using make one simple twitch catastrophic.
* Non-organic shapes can be difficult.
* In my experience, most of the details like this fall on seams, and cutting into them will weaken the piece.
* Most often we are working along curved surfaces, making the removal difficult.
Additive
Pros:
* It is easy to build up material.
* Since we are cutting the materials before assembly, the edges can be extremely crisp and clean.
* Harder to make a catastrophic mistake with a blade or a bit.
Cons:
* It will cost more. You are adding material to your build.
* It will weigh more. In most cases, the additional weight will be negligible, but it can be a problem in some cases.
* It can be problematic to align pieces precisely.
* It is possible to make a catastrophic error while using contact cement by twitching and attaching two parts in the wrong alignment.
With all that in mind, I am going to work with the additive method. Partly because I like the clean edges I can get with it and partly because this is a good chance to show y’all how to do it. I mean, this is a whole tutorial, right?
So, we are going to Look at the helmet and figure out the dimensions of the grooves and the best way to pattern them. If you think way back to episode 3, we measured the grooves. I did it there because I didn’t think we’d be coming back to Armorsmith so much.
Since we did this before, we know that the groove in the center of the helmet is half a centimeter wide (5 mm). While this is pretty clear, we are going to have to take some artistic license with where we are going to add these panels.
Since Armorsmith gives us the clearest view of what we are looking at, I am going to load up our armor fitting file one last time… for the helmet… hopefully.
When we do, we need to load the pattern for the first helmet we imported and then undo the unwrapping by clicking on this.
Go ahead and click okay. Don’t worry, we’ve already gotten everything else from this model, so it is okay to undo it. Let’s take a look at the model with a discerning eye. I do this by rotating it and clicking on the different sections to make sure we understand how it all fits together.
As you can see, on each side of the helmet, there are 3 and a half grooves (the middle one is the half). We could try to make them equal on each side of the groove taking 2.5 mm out of each of the pieces, but that would be a nightmare. So… what we are going to do is make a second panel on all of them and move the top edge down a bit.
The first thing we need to do is make a guide. We have some curves on the helmet that will make precise adjustments difficult so we are going to design out own measuring tool. Let’s open our file in Inkscape. Click on the ellipse/arc tool.
Click and drag to make an ellipse. When you let go, you will have a new path. Up at the top, there is a height and width. If the numbers are different, click on the lock between them and make sure they are the same. This will make sure your shape is a circle.
Click the lock again. Over in the layer panel, rename it. I called mine “Measuring tool.” Then right click and select duplicate. In the layer panel, you will see another new shape. Rename it. I called mine “Measuring tool inside.” Then go back up to the width and height and make it 8 mm smaller. This will give you 4 mm all the way around.
However, because of how Inkscape anchors things, it shrank the bounding box in the direction of the anchor point. So, we need to adjust it’s location by clicking on the plus and minus buttons on the position indicator just to the left of the size indicator.
Move the inner circle until it is even all the way around. Then shift-click on both of the layers in the layers panel to select them both. Right click and select “Group.” Then rename the group for easy reference. I called mine “measuring tool.” This is what I have in my file.
Imports is the layer that has all of the shapes we defined in Armorsmith. Pattern pieces are our refined shapes. Utilities is for extra stuff that we will be able to use to assist us with this part.
I hear you asking, “But I thought the grooves were 5 mm wide?” This is true. However, we are applying a piece of material to the outside of another part. The curvature is going to add a little bit extra. While typing this, I realized that the top groove has to be split in 2, so I need to duplicate this tool I just made and adjust in inner circle so that it has a 2mm gap. That way each side of the center line is identical.
Since we are preparing this for a pattern now, I went ahead and created new layers name “10mm foam”, “5mm foam”, and “1-3mm foam.” I suspect I will be using 3mm foam for adding the grooves, but I am not quite sure, yet.
I did this at this step because I am going to create the additive parts on the 1-3mm layer as we work. First up is this part.
We are going to rename this one. I like to format it as Number-position. So this piece would be 1 center. For pieces with symmetry, I always start at the center and work my way outward. After I rename it, I am going to drag it to the 10mm foam layer. Then I am going to duplicate it. We will rename that duplicate 1a center top. Then drag that duplicate into the 1-3mm foam layer.
Make sure you have 1 a Center top selected and activate the node tool.
Then we are going to adjust the edge of that piece to be 2mm away from the center line. Eyeball it for now – we are going to use the 2mm tool we designed a couple minutes ago to make sure it is all the same distance away. It should look like this.
Once you have done that, drag the 2mm measuring tool all along the lines to confirm we have the distance set in a uniform manner. The picture below should make it clear.
We want to do that all the way up and down the shape pieces to make sure those lines are pretty much 2mm apart. Then we are going to do the same for this part. The groove needs to be on the side that connects to 1 Center. I am going to drag the piece into the 10mm foam layer > rename it to 2 Visor > duplicate it > Rename that part to 2 a Visor top > and drag that part into the 1-3mm foam layer. Then I will use the 4mm measurement tool to create the groove.
You should end up with something that looks like this.
We are going to do the same thing for these two parts.
Just remember that we are doing this along the topmost edge of both pieces. That way the groove is consistent. Additionally, on that last piece, I am going to cut it off where the original piece sat to give the side piece something to lay against. When we are done, we should have something like these two pieces.
And just like that, we are ready to make this into a pattern/laser cut file!
November 24, 2025
