How to Design Origami / Geometric Cakes and Desserts in Tinkercad

In this Instructable I'll show you how to design geometrical objects in Tinkercad and then make them into silicone molds for origami cakes or dessert. 

These kinds of cakes are a relatively new trend on the internet, so it's possible you've never seen them before. There are special flat silicone molds you can buy and make your own origami cake, but I prefer to make my own molds as the ones you can buy are a bit finicky to use and there aren't many varieties to the shapes and sizes. 

Once you've made your mold you can use it to make a regular cake with frosting on the outside and sponge inside, you can freeze ice cream in them, make the outside shell out of chocolate and fill the inside with mousse, you can fill it with jello with bits of fruits.

Possibilities are endless and whatever you make, you will end up with a gorgeous design. You can even make several cake molds in different sizes and shapes and stack them together to make a real showstopper. 

Geometric designs look best when covered in coloured buttercream or dyed chocolate, but you can also spray paint them with special food dye sprays or even dip them in a mirror glaze. 

Content:

Steps 1&2 - Design in Tinkercad

Steps 3&4 - 3D printing

Steps 5&6 - Silicone mold preparation and pouring

Steps 7&8 - De-molding and reassembling

Steps 9&11 - Cake assembly

Step 12- Alternative methods

3d printer and filament (PLA) 

Basic knowledge of Tinkercad 

Food safe silicone rubber (flexible type) 

Melamine or glass board 

Super glue, some clay or plasticine

Baked cake slices and filling, for example buttercream or ganache

Piping bags and spatulas

If you want to design your own cake I recorded a video so you can see how I do mine. I've been told my method of designing is a bit odd, but it absolutely works, so it's worth checking out even if you don't plan on making a cake. My favourite designs are based on triangles, particularly tetrahedrons as they are incredibly easy to use and very versatile.

Alternatively you can use any of the other designs I provided below or simply find something on the internet.

This step is optional, as you can make a mold form out of other materials such as wood, adjustable mold, acrylic panels or easy release round baking pan.

I prefer to design and 3D print my own forms because it gives me more control and allows me to design exactly how thin or thick my silicone walls will be. It's especially important if you have a lot of undercuts and you need the silicone to be thin and flexible.

Take your chosen design and import it into Cura.

When I print my "cakes" I usually print them as disposables. They essentially have just one thin wall and are only used to make a silicone mold. They take a long time to print because you have to print in high quality, slow and with retraction, so to reduce the printing time (when possible) I like to use Spiralise Outer Contour mode. I set my perimeters to:

-line width: 0.8

-bottom thickness: 3-4 layers

-top thickness: 0 layers

-retraction: on

-no brim

I end up with a vase-like object that's thin and flexible, albeit strong enough to withstand handling.

**Sometimes, when I make small cakes and don't want to bin the "cake" print after the mold is created, I cover the inside walls with a layer of air dry clay to stiffen it, and use it as a planter or a pen holder.

I like to print it in medium quality, 15-20% infill, because it's only meant to be strong and functional, doesn't have to be pretty.

If you are not sure how much silicone you will need, you can figure it out using grain/rice/sugar method. Place your plastic form in a flat bottomed container (like casserole dish), place the "cake" print inside (bottom facing up, you don't want to pour any grains into the opening of the "cake") and pour grain inside. You can use rice, millet, couscous, sugar or salt and so on. Pour all the way to the top and then tip it out and measure the volume (with measuring cups or a measuring jug) of the grain to determine how much silicone to use (use a little bit more silicone than the grain indicated, just to be sure, around 5-10% more)

That done, prepare for the silicone pour:

1. Use a pencil to trace an outline of the plastic form onto a melamine board, then position the "cake" print in the middle and trace an outline of that as well.
2. Apply a few drops of superglue to the rim of the "cake" print and glue it to the melamine board (align it with the pencil tracings).
3. Brush cooking oil (coconut, sunflower, olive etc) all over the surface of the "cake", but try not to get too much of the oil onto the melamine board.
4. Spray the inside of the plastic form and the 3D printed base/lid with mold release or cover it with strips of scotch tape.
5. Apply few drops of superglue to the edges of the plastic form and glue it to the melamine board (align it with the pencil tracings).
6. If you are worried your form is not leak proof, you can press some clay or plasticine around the rim of the form where plastic meets the melamine board.

Measure the necessary amount of silicone and mix according to the manufacturer's instructions.

Slowly pour it into the form from a distance (~2 feet height), try to maintain a slow and steady, thin stream of silicone to avoid air bubbles.

Pour nearly all the way to the top of the form and fit it with the base/lid. If any silicone overflows through the hole, just leave it be, it will be easy to cut it off later.

1. Use a sharp knife to cut off any excess overflowed silicone from the base.
2. Pry open the base from the form.
3. Use a knife to gently, carefully and slowly cut into the slits down the middle of the plastic form to separate two halves and pry them away from the silicone.
4. Peel the silicone away from the "cake" print.
5. If your silicone is too thick or not flexible enough, you might need to cut a zig-zag line on one side of the wall from top to bottom.
6. Wash the inside of the silicone mold with a gentle detergent, rinse and dry with paper towels.

Align both halves of the plastic form and secure them together with paper clips.

Slip the silicone mold into the form and fit it with the base/lid.

Cake assembly method will depend on the type of desert you are making, thicker cream will have to be piped and spread with a spatula, looser creams (such as ice cream mixture, ganache, jelly, chocolate) have to be poured into the mold.

I'm using American buttercream which has a thick and spreadable consistency. Because it's not liquid in any way, I have to apply it to the mold with a spatula in several layers. 

Firstly, I piped some buttercream onto the walls and used an offset spatula to spread it all around the walls pressing the cream into the triangles. I made several passes to make sure all those small nooks were filled. Then, I let it firm up in the fridge. 

Second layer consisted of spreading more cream onto the walls (thin layer) as well as the bottom of the mold. And again, I left it in the fridge to firm up.

Third step was adding the cake (small discs) to the form and alternating it with ganache.

So, once I took the form out of the fridge, I piped a thick layer of ganache (pale yellow) to the bottom of the mold, then pressed one cake disc into the ganache.

You want to pipe a thick layer of ganache or buttercream, so that when you press the cake into the mold, the excess cream raises up the sides of the cake disc. You need that excess to fill in any gaps down the sides of the cake.

Then, you pipe more ganache to the top of the cake disc and press another cake slice on top and repeat until you get to the top.

Make sure that the top most layer of cake is either level with the silicone mold or protruding a little bit ( you can always use a knife to level it). But don't cover the top with the cream. You need the last layer (which will be your cake bottom) to be uncovered. If you run out of cake by the end, either bake more cake or, if you only need a few millimetres, you can press a large, plain, flat biscuit(s) (cookies for Americans) to the top. You need a firm base for the cake otherwise the bottom of the cake will sink down under the weight. 

I left my cake in the fridge to firm up and then carefully demolded it. There were a few imperfections on the top, which I filled and levelled with a small spatula using leftover buttercream. You can use leftover buttercream to repair any imperfections along the walls as well. 

Transfer the cake onto a stand and decorate.

A) If you can't or don't want to use silicone you can use a gelatine and glycerine mold making technique (the link will take you to a YouTube video demonstrating that method). It's cheaper than silicone, can be melted down and poured again, but it's not as flexible as silicone rubber and is only viable for a few days before it hardens and becomes inflexible or develops mold (the bad type). You will also be limited to smaller desserts and simpler designs.

B) You can print a one-off mold, but only for smaller desserts, less complicated designs and absolutely no undercuts. I call it one-off , disposable mold, because I don't recommend using 3D printed objects with food. Especially food that grows bacteria like butter or eggs. I know there are some filaments that are supposedly food-safe, but I'm not entirely convinced. You can use this mold one time only and then throw it out.

Yellow cake in the first picture was made using this method, second, third and fourth picture show you what that disposable mold looks like and how you have to cut away a wall to open the form up.

I grabbed a geometric solid object, added wings for paperclips down the middle and then sliced that object in half. Then imported that half to Cura and printed using Spiralise Outer Contour mode with 0 bottom layers and 0 top layers AND 5-10mm brim. I printed bot halves, cut away the flat walls, clipped them together with paper clips and glued the mold onto a thin plastic sheet by adding a few drops of super glue to the brim.

C) Last idea is to use vacuum forming to make flat dessert molds. This works particularly well with flat chocolate bars or individual pralines. Instead of designing a geometric container, make a geometric chocolate bar, 3D print it and use vacuum forming to make a flat, plastic (food safe plastic) mold.

**Last two pictures were taken from the internet to give you an idea of what I'm taking about.