3D Printed Sea Urchin Light

This project has been a little while in the making and it’s exciting to finally be writing about it. About a year ago I posted about 3D scanning some shells, and as part of the scanning I captured a sea urchin shell. At the time I didn’t know what I’d do with it, but fast forward a year and I’ve found a perfect application; turning the sea urchin shell into ceiling light covers in my house.

In this post I’ll go over the main processes and experiments I went through to get the finished product, but in case you’re just here for the big finale, here’s the link so you can download the final Sea Urchin Light exclusively from my Pinshape account and 3D print as many as you like!

3D Scanning

As explained in further detail in my previous post, I used an EinScan Pro 2X Plus 3D scanner, which included a turntable to automatically capture all angles of the sea urchin shell. This resulted in a full-colour, highly detailed model of the shell, as shown to the right. However, as anyone familiar with 3D scanning will know, this model is just a skin with no thickness or solid geometry, and was just the starting point for the design process.

Design

If you don’t have access to expensive CAD programs, good news; this project was completely designed in free software! I’ve used Autodesk Meshmixer for many of my tutorials and posts, it’s a surprisingly powerful tool and a must for anyone involved in 3D printing. Additionally, it’s quite useful when you are working with 3D scan files, which are typically a mesh like a STL or OBJ. The process took a little time, but has been outlined in 6 basic steps below:

1. Fill any holes and errors in the 3D scanned sea urchin shell. In Meshmixer, this simply involves using the “Inspector” tool under the “Analysis” menu.
2. Scale up the shell to the appropriate size, then use the “Extrusion” tool to thicken the skin into a solid shell. So that the shell would allow a lot of light through, I used a 0.7mm thickness for the overall design.
3. I wanted to create an interesting pattern when the light was turned on, so separated several areas of a copy of the original mesh to be used to create thicker sections. This was a slow process of using the brush selection tool to remove areas, before repeating step 2 with slightly thicker geometry. For this design I ended up with 3 different thicknesses around the shell.
4. To allow the light fitting within the shell, a larger opening was needed at the top. A cylinder was added from the “Meshmix” menu and placed in the centre.
5. By selecting both the shell and the cylinder together, the “Boolean Difference” command became available, subtracting the cylinder section from the shell.
6. Lastly, a neck section measured off the original light fitting was added. I cheated slightly and modelled this in Autodesk Fusion 360 (also free if you’re a student), but you could use Meshmixer – it would just take a bit longer to get accurate measurements. Then the separate parts are joined together using Boolean Union, and the design is finished.

3D Printing

As well as the new design needing to fit the geometry of the existing light fixture, it also needed to fit the build volume of the 3D printer – in this case a Prusa i3 MK3S. As you can see below, the shell is only slightly smaller in the X and Y dimensions than the build plate.

In terms of print settings, I stuck with some pretty typical settings for PLA, including a 0.2mm layer height. Support material is necessary with the light printed with the neck down – this is the best orientation in terms of ensuring the surfaces visible when standing below the light (remember, it is ceiling mounted) are the best. Where support material is removed is always going to be messy, and you wouldn’t want to have these surfaces being the most visible. Overall, this meant that each light took ~32 hours to print.

Material & Finishing

One of the steps that took a bit of experimentation was choosing the right material in order to look good when the light was both on and off. Each of these lights are the main, or only, sources of light in the spaces they are installed, so they need to provide a good amount of light.

As shown above, 3 different materials/finishes were trialled. Initially I began with a Natural PLA from eSUN, which is a bit like frosted glass when printed. While this allowed all the light to escape and illuminate the room, most of the detail was difficult to see in both the on and off settings. It was just like a random glowing blob. I then tried pure white PLA, hoping that the print would be thin enough to allow a reasonable amount of light out. Unfortunately very little light escaped, however, the shadows from the different thicknesses looked excellent, and when the lights was off, it was very clear this was a sea urchin shell. Perhaps this would be a good option for a decorative lamp, but not so good for lighting a whole room.

So the “Goldilocks” solution ended up being in the middle – I 3D printed the shells in the translucent Natural PLA, and then very lightly spray painted the exterior with a matt white paint. Just enough to clearly see that it is a sea urchin shell when the light is off, and translucent enough to allow a lot of light out. Perhaps there is a material/colour of filament that would achieve this with needing to paint, but I didn’t want to have to buy rolls and rolls in order to find it. PETG would be interesting to try, and if you have any other suggestions, please leave them in the comments section.

The Result

To the right are the dimensions of the ceiling light fixture within which the sea urchin light comfortably fits. The light itself is a standard B22 fitting, so the sea urchin can comfortably fit most standard interior lights. However, if you have a different sized fitting, or want to fit it over an existing lamp, you can easily scale the design up or down to suit your needs. I’ve already fitted one of the early small test prints over an old Ikea lamp, it just sits over the top of the existing frame. In total I’ve now installed 5 of the large ceiling light covers in my house, and am planning a new design to replace some of the others (my house is full of this terrible cheap fitting!).

As mentioned at the beginning of this post, I have made this design exclusively available on Pinshape – it’s just a few dollars to download the file, and then you can print as many as you like! If you 3D print one, please share a photo back onto Pinshape, I love seeing where my designs end up and what people do with them.

– Posted by James Novak

3D Scanning Natural Forms

This is a post about my new favourite toy – the EinScan Pro 2X Plus 3D scanner from Shining 3D. Why? Because it allows you to turn any object into a 3D model! And I can tell you upfront, it works REALLY well!

This is not the first 3D scanner from Shining 3D, which is a good sign that both their hardware and software has had time to mature. The EinScan Pro 2X Plus is brand new to the market, which means there are not many reviews at the time I’m writing, although you can find a brief overview from 3D Scan Expert and will no doubt see a full review from him in the near future. I’m not a 3D scanning expert, so am not going to dive into all the details here. I have used several scanners in the past and written a few posts, but this is the first that I have full access and control over and am currently using on a daily basis.

Enough with the introductions. One of my first experiments has been to 3D scan some challenging organic forms, including some shells which I picked up from the beach. The top photo shows one of these shells being scanned (we have the “Industrial Pack” turntable and “Colour Pack” upgrades for the scanner). The process is straight forward in the accompanying EXScan Pro software – a few basic settings about the detail you’d like to capture and press go. The turntable and scanner do the rest, and you can see the points being captured in real-time on screen. There is a bit of cleanup after the first scan to remove any points that aren’t needed (e.g. you can see in the photo some points around the perimeter where the scanner picked up an edge of the turntable), at which point you have your first scan.

This could be all the detail you need depending on your application; however, all you have is an outside collection of points, with no detail about the inside of the shell. So I then flipped the shell over and performed a second scan. The only difference from the previous step is that now there are 2 scans. Amazingly the software is proving quite intelligent at automatically aligning multiple scans, finding common points and bringing them all together. This doesn’t always work, and there is an option to manually align 2 scans by selecting 3 common points in each. I must admit the interface for this process is quite painful to use at the moment, so it’s always great when the software automatically does this. Overall the software is very basic, you really don’t have a lot of control – which can be both a blessing and a curse. You certainly can’t perform any sort of editing actions other than selecting and deleting points.

The final step is to turn all of the points (aka. point cloud) into a mesh suitable for 3D CAD software, or 3D printing. There is an option to create a watertight mesh, letting the software automatically fill any holes in the model. For this shell scan I only had very minor gaps which were nicely cleaned up and blended into the mesh. However, I have found with some other scans that if holes are quite large, or there are some messy overlaps in scan data, the software will produce some weird results – best to keep scanning to capture as much data as possible before creating a mesh, once you get to this step there is no turning back.

Best of all, being a watertight mesh, the file can be immediately used for 3D printing. But why simply replicate a shell? I always see large shells as decorator items in stores retailing for hundreds of dollars – and now I can 3D print them for a fraction of the price. This one was scaled up 500% and printed on a Wanhao Duplicator D9/500 – which is still working somewhat consistently after my previous post and firmware upgrades. I decided to print it in an upright orientation so that the 0.5mm layers are similar to the layers naturally occurring in the shell. Even though the print quality is still quite rough, I think this only adds to the natural effect.

Scallop Shell Half by edditive on Sketchfab

The shell has been saved as a .obj file, meaning that it has all the colour information along with the geometry that would normally be a .stl file. I have shared this on Sketchfab so that you can have a closer look at the mesh in 3D using the above viewer. I think it’s a really great result, and hopefully you can see why I have called this my new favourite toy. It really does open up new opportunities (perhaps you’ve already seen some new experiments if you follow me on Instagram). Stay tuned, I’m sure there’ll be plenty more posts that involve 3D scanning and 3D printing in the future.

– Posted by James Novak