Recently, I’ve been creating 3D cut and fold patterns for Cricut, and it’s been a learning endeavor. Here are my current suggested best practices.
Initial Design in Inkscape
The Cricut Design Space program is completely useless as a design environment for custom shapes. I use the free program Inkscape to create my graphics.
For roughing out shapes, use the Document Properties window so select a unit of measurement (inches or cm) and create a grid with closely spaced lines of the minimum unit you’re likely to want in your design. I like to use metric because the math is easier — do you know the decimal expression of 13/16″ offhand? — and 1mm or 2mm are reasonable grid intervals for your minimum step size, whereas 1/10″ is a bit large.
Snapping — either to grid intersections, grid lines, or corners/handles, makes everything much easier. There are two shortcuts you’ll find useful: % to turn snapping on or off, and # to turn grid on or off. You can use these keys while drawing a line, which is very helpful when you want to start the line at a gird point and end it at a control point, for instance.
One non-obvious feature I’ve found helpful is the ability to measure the length and angle of a line. You do this with the Bezier/line tool (B). Start to draw a line, snapping to the endpoints of the line or segment you want to measure. The length and angle of the potential line is displayed in the status bar (you may need to zoom in to make it show up). Press Esc to not actually draw the line.
To measure the angle between two lines neither of which is horizontal or vertical, measure the lines separately and then calculate the angle. E.g. if one is at 12° and the other at -54.3°, the angle between them is 66.3°.
When working with a shape, as opposed to a line, I set the fill color but no stroke color. That’s because I like to see the precise size in the toolbar. If there’s an outline the width of the outline is included, so a 2″ square might show as 2.03″ wide. Until the last stages, my drawings usually look like a bunch of multicolored blocks.
When using lines, the width and height shown on the toolbar also incorporate the “cap” of the line, so to report the true length from endpoint to endpoint, choose the first cap style (“butt cap”), which doesn’t extend the line beyond the endpoints. This works if the line is horizontal or vertical. To get a true measure for a slanted line, you’ll have to use the measurement method described above.
The CTRL key is your friend, for resizing while preserving aspect ratio, shifting objects, or moving control points either horizontally or vertically.
When creating a 3D folding shape, it consists of flat (or curved) surfaces whose edges are either folds or cuts. To aid in snapping things together and adding in fold lines and extra cut lines, I make each of these a separate shape so that they have control points at useful places and can be easily duplicated and rearranged.
Often you’ll want to have shapes that meet at angles. If you have two surfaces that meet at a corner and that line isn’t horizontal or vertical, it can be tricky to get the corners to snap. You can get them to meet at one corner, but then how to get the others together? If you rotate a shape, it doesn’t rotate around a corner, so the corner you already snapped will also move. However, if you get the object into rotation mode, you can use the mouse to drag the rotation center — a little crosshairs. The “Snap an item’s rotation center” toolbar button lets you position that crosshairs to a control point — such as a corner of a shape — so you can rotate with that point as the center.
Inkscape has a “layers” feature. The SVG file format doesn’t have a way to distinguish between a score line, a cut line, and a draw line, so use layers for this — have a “score lines” layer, a “cuts” layer, etc. When you “upload” the drawing into the Cricut Design Space, layers are converted into groups, which makes it much easier to find everything that’s supposed to be a score line and make it a score line, in a single step.
Note: Groups in the SVG file also are kept as groups in the import.
Cricut is good at cutting the complete outline of a shape. When making “tab A into slot B” designs, though, you often have extra cuts that touch the edge of a shape. Cricut’s cut sometimes doesn’t quite make it all the way to the edge in this case, leaving a corner that has to be torn apart. It’s a good idea to extend such cut lines slightly to ensure separation. If you don’t want to go past the line, turning a corner and following the edge of the shape for a short distance also does the trick.
Widen edge slots
Keep the thickness of the material in mind. If you intend to use light cardstock, a single cut will often suffice as a slot to insert into another slot. However, if the material is thicker or the slot is very near a corner, the material may be deformed by being forced apart to accommodate whatever you put into the slot. In that case, make the slot wider (which also lets you make it part of the shape’s outline instead of a separate cut). To convert a line into a slot of a specified width:
- Set the line’s stroke width to the slot width you desire
- Set the endcap style appropriately bearing in mind that the outside edge you see now is where the cut will be.
- Extend the line a little outside the object edge so the corner doesn’t have jaggies when you turn it into a cutout.
- Convert the line to a path (menu Path > Stroke to path).
- Use menu Path > Difference to cut that slot into the outline of the shape.
Secure tabs
It’s nicest if you can make your design to work without adhesives. If you have slots along an edge, how securely they grip whatever you slot into them can depend on the thickness of the material.
If you have interior slots to insert tabs into, you can have multiple tabs with overlaps facing in different directions to lock into position. You have to bend the material a little to insert them, then they are secure.
(Again, consider the thickness of the material and whether to make slots wider).
Flexible designs
As you do your design, bear in mind that Cricut Design Space has no simple way to modify an individual shape. If there are interior decorative cutouts, make them separate objects, not actual cutouts within the big outline (i.e. use separate Path objects). That way, it’s possible to move or remove them without going back to Inkscape.
Bring into Cricut
Use the “upload” feature to bring your SVG file into the Cricut Design Space program. When you add the upload to your canvas, text will be removed (this is so stupid — I complained to Cricut about it, feel free to add your voice). Layers and groups in the SVG will be converted to groups in the canvas. The entire design will also be a group, so your layers will be subgroups.
Look at the toolbar to see the dimensions of the design, and compare that to the correct dimensions in your SVG file. They are probably not the same. Use the padlock icon to lock the aspect ratio. Type in the correct width or height.
Ungroup the top level of the design. Find the subgroup that contains all your score lines (just click on any score line and the whole group will be selected). Use the toolbar to set the operation to Score for those entities.
Note: Be careful when clicking things to select them because it’s extremely easy to move them by accident.