I decided to make this because we keep chickens and often find ourselves running out of places to put all of the eggs.
Truth is we probably have too many.
After making this I actually ended up giving it away as a Christmas present so this instructable has been put together using the photos and files I had, bearing in mind I never intended on documenting it. Sorry for any gaps.
Step 1: Measure a Large Egg
Pick the largest egg your hens usually lay and measure it's diameter at the largest point and it's length.
Step 2: Model the Egg
Using a CAD package of your choice (I used Autodesk Inventor Professional 2016) model the egg from the measurements you took. Please note: the CAD package must support free-form modelling.
I modelled it as a revolution, as shown in the sketch.
Play around with the radii until it looks like an egg, even if you happen to have a radius gauge set to hand, it's unnecessary, by eye is adequate.
Revolve it into a solid object then thicken it.
Thickening can be done in the sketch stage, but I found it easier to thicken the egg by 2mm all around its surface after I had modelled it.
The reason for this is because we don't want the eggs to be a tight fit in the pockets, we need to give each egg a bit of clearance.
Step 3: Create Axis to Align the Eggs
As a new part file, create two planes a distance apart (I made this 120mm between them).
On the top plane, create two circular point patterns.
I chose to have 3 points around the inner circle and 9 on the outer, at 60mm and 140mm diameters respectively.
Project these points onto the lower plane and generate work axis between the corresponding points.
Step 4: Align the Eggs on the Axis
Constrain the eggs to the work axis.
Trial and error is needed here, I was aiming for two spirals of eggs leading up to the inner nest at the top.
I ended up with 5 eggs on one spiral and 6 on the other, plus the three in the nest at the top making 14 eggs total.
As I said, it was trial and error and I fiddled around, moving the eggs up and down the each axis until it looked how I wanted it to.
Step 5: Create a Freeform Cylinder
In the egg assembly, create a large freeform cylinder on a new workplane (75mm below the top plane)
I chose to split it up into as many faces as my PC could handle which was 8 high and 12 around. If my PC could have handled it, I would have done more to give as organic shape as possible.
I simply dragged the diameter and height until the model engulfed the eggs in diameter and came up about 1/3 to 1/2 the way up the 3 eggs in the top nest. The bottom of the cylinder comes down to an adequate thickness below the bottom eggs.
Step 6: Manipulate the Freeform Model
Now the fun really begins.
This part took me most of an evening.
The idea is basically to push, pull and rotate the faces, edges and corners, uncovering the eggs one at a time.
I aimed to have at least 60% of the eggs uncovered (the top 60% of the egg obviously).
Take care to leave enough wall thickness in areas where space is tight between eggs on different layers.
Step 7: Only Finish When You're Happy With It!
As I said, this took an entire evening.
This is the shape I was happy with, but that's just personal preference, this was my first time modelling anything like this; a completely freeform organic shape.
I made it yellow in colour as I knew this was the colour I would print it. I thought yellow would best complement the colour of eggs.
Step 8: Sculpt the Eggs From the Nest
Using the Sculpt feature, remove the egg shapes from the nest.
This basically just cuts out material anywhere where the egg and nest material is conflicting, you have to choose which one you take from the other (I.e if you do it the wrong way around you'll end up cutting the bottoms off all of the eggs and the whole nest itself disappears).
Step 9: The Model Is Complete
All that is left to do is export the model as an STL file for use with a 3D printer.
Step 10: 3D Print!
This step took 3 days, it used up around 350g ABS filament.
I used my Ultimaker 2 3D printer using the following settings:
35mm/s print speed
As with all my prints I print on blue decorators paint which I rub down with coarse emery paper after application to the print bed.