Pi-Ides of March: 3D Printed Ides of March/Pi Day Cookie Cutters and Mini Pies Using Adobe Fresco and TinkerCad

As a fan of the circle constant and desserts, Pi Day, March 14th, is a holiday I am always eager to celebrate. Many of my friends are history students, who celebrate the Ides of March in their classes each year. The Ides of March, March 15th, is the date when Julius Caesar died in 44 BCE. These back-to-back holidays create the unique opportunity for two days of nerdy celebration that my friends and I have dubbed “The Pi-Ides of March”. This year to celebrate, and to enter into Instructables’ All Things Pi Contest, I used Adobe Fresco and Autodesk TinkerCAD to create a cookie cutter and stamp of Julius Caesar and the pi symbol in front of a pie and used it to bake mini hand pies stamped with the design.

To Create a 2D Cookie Cutter Template:

1. A drawing tablet or Ipad
2. The free Adobe Fresco app
3. An idea, sketch, or refrence photo
4. A PNG to SVG converter such as Adobe's free SVG Converter or Adobe Illustrator

To turn your 2D cookie cutter template into a 3D CAD file you will need:

1. Autodesk TinkerCAD

To print your cookie cuttters you will need:

1. A 3D Printer and compatable slicer
2. Filament

To make the hand pies you will need:

1. Pie Dough
2. Chocolate Blackberry Filling
3. 1/2 cup frozen blackberrys
4. 1/4 cup light corn syrup
5. pinch of salt
6. 1 Tbs cocoa powder
7. 1 tsp corn starch
8. 1 tsp vanilla
9. 1/4 cup chocolate chips
10. Baking Sheet
11. Parchment Paper
12. Oven
13. Microwave

Open the Adobe Fresco app. Start a new custom size document. Change the units of the document from pixels to your preferred units of inches, centimeters, or millimeters. I used inches. Set the dimensions of the document to the maximum dimensions of your cookie cutter. The largest size your cookie cutter can be is your 3D printer's print bed dimensions. I set my document size to 7in by 7in.

If you are using an image as a reference for your cookie cutter import it to a new layer using the image button. If you are sketching your cookie cutter stamp design create a new layer. Select either the vector or pixel drawing tool. Set your pen color to red. Sketch out your design, making sure to leave at least one inch of space around the design. This will allow for the stamp to fit inside of the cookie cutter. The red areas you draw represent the areas that will be indented when the stamp is pressed into your cookie dough or pie dough. I drew Julius Caesar and the Pi symbol in front of a pie.

Create a new layer above your previous layers. Select the vector drawing tool. Set the vector smoothing to a number above 50. This will give your design smooth consistent edges. I set my smoothing to 76. Set the pen size to 10 or larger. Set the pen color to black. Trace your design. You may have to modify your design slightly at this stage to have less detail due to the large pen size. A pen size of 10 or greater will allow your stamped design to be more visible in the finished baked goods. Once you are satisfied with your final stamp design, hide your sketch and reference layers. Download the PNG file of your stamp design with no background.

Stamp details need a back/baseplate to set on. This is the next piece that needs to be designed.

Create a new layer below the stamp design layer. Select the vector drawing tool. Set the pen size to 20. Set the color to a new high contrast color. I chose blue. Loosely outline your stamp design, making sure your outline is a closed shape. Select the paint bucket tool. Fill the outline shape. You have now created a base for your stamp indentions. Download the PNG file of your stamp baseplate with no background.

Next the cookie cutter's edge needs to be designed.

Click on the Stamp Back layer. From the option list that apears, select Set as Reference. Create a new layer above the Stamp Back layer. Set the color to a new high contrast color. I used orange. Make sure that Paint Inside is turned on. Setting a reference and turning paint inside on will allow the Stamp Back layer to act as a stencil, preventing the area the Stamp Back layer covers from being drawn on. Loosely outline the Stamp Back layer. Download the cookie cutter edge PNG file.

To make the cookie cutter easier to use, a handle can be added.

Click on the Cookie Cutter Edge layer. From the option list that apears, select Set as Reference. Create a new layer below the Cookie Cutter Edge layer. Set the color to a new high contrast color. I used yellow. Select the paint bucket tool and click inside the Cookie Cutter Edge shape. This will allow the handle to sit above the cookie cutter's edge on the final cookie cutter. Make sure that Paint Inside is turned on. Select the pen tool. Loosely outline the Cookie Cutter Edge layer to your desired handle thicknes. Download the cookie cutter handle PNG file.

To import images into TinkerCAD they need to be SVGs. One way PNGs can be converted to SVGs is by using Adobe Illustrator.

Open the PNG in Adobe Illustrator. Select Image Trace. Select Expand. Ungroup the newly expanded image. Now that the image is able to be manipulated in Illustrator, delete unwanted areas. This process can be easier visualized by creating a colored layer below the area you are working in. Once the unwanted content is removed, hide all views other than the view with the image on it.

Select File then Export then Export As. When prompted, change the file type to SVG and name the file. A SVG Options prompt should then apear within Illustrator's interface. I use the SVG options of:

1. Styling: Internal CSS
2. Images: Preserve
3. Object IDs: Minimal
4. Decimal: 2
5. Responsive

On the SVG Options prompt the SVGs code can also be viewed. If you encounter problems importing the SVGs into TinkerCAD, checking the SVG's code to see if it falls within TinkerCADs supported SVGs elements may help provide a jumping off point to remidy those issues.

Another option for converiting PNGs to SVGs is using Adobe's free PNG to SVG converter: https://www.adobe.com/express/feature/image/convert/svg

Open a new project in TinkerCAD. Import the cookie cutter stamp SVG. Double check that the created 3d extrusion looks the way you want. If your imported extrusion has extra unwanted filled areas you may need to use a different SVG converter. Tinkercad can only process certain SVG elements. More information on Tinkercad's SVG requirements can be found here: https://www.tinkercad.com/blog/import-and-export-svg-files-tinkercad.

Set the snap grid to 1/8". Adjust the height of your newly imported extrusion to 1/4". Do not modify the other dimensions of your design yet. Ensure the stamp design is sitting flush on the workplane.

Import the stamp back SVG into TinkerCAD. Set the stamp back's height to 1/8". Move the stamp back extrusion down until it is directly on top of the stamp extrusion. Select both the stamp extrusion and the stamp back extrusion. Click on the group button or use the keyboard shortcut Ctrl + g to combine the two shapes.

It is important to assemble your project face down so that your cookie cutter is a mirror image of your final design.

In the same file that the stamp was assembled in use the same method to assemble the cookie cutter.

Import the cookie cutter edge SVG. Set the edge extrusion's height to 1". Import the cookie cutter handle SVG. Set the handle extrusion's height to 1/4". Move the handle on top of the edge and merge the extrusions together.

Now that the stamp and cookie cutter are both assembled they can be resized together if any size adjustments are needed. It is important to resize the components simultaneously to ensure they are proportional when 3D printed.

Export the designs as STL or OBJ files for 3D printing.

Upload the STL/OBJ files to the slicer of your choice. Make sure to scale the cookie cutter and stamp to the same size. Depending on the printer being used, printing with a lower layer hieght and higher infill percentage can make the cookie cutters easier to clean. Never clean a 3D printed PLA cookie cutter a dishwasher as there is a high chance it will melt or warp. I encountered some printhead issues while printing, so my cookie cutters did not come out as crisp as I had hoped, but I still used the prints in further steps in order to complete in time for the Pi-Ides of March.

These cookie cutters can be used to make any variety of treats. I used them to make mini hand pies with a blackberry chocolate filling. The filling is very thick and has a poptart like texture, and can be made in a microwave. When microwaving corn syrup it is important to exercise caution when removing the filling from the microwave.

To make the filling:

1. Gather Ingredients:
2. 1/2 cup frozen blackberries
3. 1/4 cup light corn syrup
4. pinch of salt
5. 1 Tbs cocoa powder
6. 1 tsp corn starch
7. 1 tsp vanilla
8. 1/4 cup chocolate chips
9. Place the frozen blackberries and corn syrup into a large microwave safe container such as a glass measuring cup. Microwave in 20 second increments until the blackberries are softened, stirring with a fork in between microwavings.
10. Lightly mash the blackberries with a fork.
11. Slowly stir the corn starch and salt into the blackberry mixture until fully dissolved.
12. Add the cocoa powder to the mixture and stir until fully combined.
13. Return the mixture to the microwave and heat in 20 second increments, stirring in between, until thickened. This should take around 1 minute.
14. Stir vanilla and chocolate chips into the mixture.

Preheat your oven to 450 degrees F (230 C).

Gather your pie crust of choice, blackberry filling, cookie cutter and stamp, and a parchment paper lined baking sheet. Hand wash and thoroughly dry the cookie cutter and stamp. Roll out the dough 1/4 inch thick. Use the cookie cutter to cut out the fronts and backs of the pies. Gently press the stamp into the dough of 1/2 of the cutouts. Applying a thin layer of spray cooking oil to the stamp can make this easier. You may have to stamp the dough multiple times to get your desired level of indention. Place 1 heaping tablespoon of filling inside of each pie. Cover the filling with stamped dough. Crimp the pie edges with a fork. For best results refrigerate the pies for 15 to 20 minutes before baking. This will help the design to stay imprinted in the final baked goods. 

Bake the pies at 450 F (230 C) for 12-15 minutes, until golden. Let cool for 10 minutes before eating.

Pi-Ides of March Pies can be served any way you like. The traditional serving method is letting each guest at your Pi-Ides of March celebration stab their pies in a dessert based historical recreation of the Roman Senate's session at the Curia of Pompey. Happy Baking and happy Pi-Ides!