Factors Affecting 3D Printed Object Strength

Steven from 3D Printer Academy released a video to his YouTube channel in early 2024 to discuss how wall line counts and infill contribute to the strength of 3D prints. The full video is here:



Bonus: the precursor to this video is here.

Strength tests were performed on 3D printed beams with grid infill and showed some interesting results. All of the following images are screenshots from the video above.

With increasing wall line count…

• Strength increases linearly
• Strength to weight ratio increases but with diminishing returns

With increasing infill percentage…

• Strength increases
• Strength to weight ratio decreases

The optimal strength/weight ratio is around 20% infill and 3 walls.

Regarding the relative strength/weight ratio of infill types, lightning infill had the highest value, and the author believes that due to the nature of lightning infill, the object is very light, so most of the strength may be coming from the walls. I agree and would also add that because lightning infill is not uniformly distributed throughout the object, the findings related to this infill type should be interpreted in that context. The infill types with the next highest strength/weight ratios were gyroid and 3D honeycomb.

Note that if you use Cura as your slicer, it does not currently come with 3D honeycomb or honeycomb infill. You can get honeycomb infill for Cura, but if you want 3D honeycomb infill, you will need to use another slicer.

Personally I like cubic and gyroid because they are “airtight” in all 3 axes and presumably could withstand forces equally in all directions. Does this information influence how you will slice your next 3D model?

How to Watch the 2024 Olympics

Did you know that there are many ways to watch the 2024 Paris Olympics? One obvious method is to watch on TV, as the Olympics have been televised on NBC for as long as I can remember. However, given that there are 39 separate sports, each with several rounds of competition leading up to the medal rounds, there is far too much live action to broadcast on a single TV channel.

For more coverage, check out the NBC Olympics website where you can watch the opening and closing ceremonies as well as selected events. The website provides a full schedule of live events as well as links to watch events live or to inform you of other streaming services where events will be broadcasted.

I am personally interested in table tennis, but that is not one of the more popular sports, so I think my only option to watch the live matches is through Peacock. Through Peacock, you can watch every competition across all 39 sports. Similar to other streaming services, you can access Peacock through most electronic devices where the Peacock app is available including Apple TV, iPhone, iPad, and Macintosh computers. You can also watch on any modern browser.

Happy viewing!

Resetting iPhone Face ID

Yesterday my iPhone 12 Pro Max stopped recognizing my face, and I had to use my passcode to access my phone. While not a huge nuisance to enter the passcode, it did remind me how convenient it is for my phone to simply recognize my face. I thought that since I have been getting older, maybe my facial features have changed enough that I needed to re-configure Face ID. Therefore, I went to Settings > Face ID & Passcode > Reset Face ID. Although I was able to clear my current Face ID settings, I had a lot of difficulty configuring a new appearance.

As you can see from the 3 photos above, the Face ID setup asked me to position my face within the frame, and despite my compliance with the request, it kept asking me to move my iPhone a little lower. I dutifully pointed the iPhone lower and lower until my face was completely out of the frame.

On a couple of occasions, Face ID accepted my face despite my face being out of frame, but Face ID logins obviously did not work. Also, when trying to turn on the “Face ID with a Mask” feature, it would attempt to verify my face and fail to do so, stating “Your face must match the existing Face ID appearance.”

Naturally my first attempt to resolve the issue was to reboot my phone. Normally I do this by simultaneously pressing the volume up and side (power) buttons, and then using the “slide to power off” slider. Then I wait a little while, press and hold the power button to restart my phone. Unfortunately the Face ID setup was still misbehaving. My next attempt to resolve the issue was to ask the internet if they have had similar problems. I found an Apple Support page called If Face ID isn't working on your iPhone or iPad Pro and did everything it suggested, but none of the recommendations solved my problem.

In some discussion forums, users reported success with erasing all content on their devices to fix the Face ID issue, but I didn’t want to resort to that until I had exhausted all other options. Finally I found a discussion thread in Apple Support Community called Face ID stopped working on my iPhone after iOS 17 update in which Allensmith98 suggested restarting my iPhone in a different way: Settings > General > Shut Down. After powering up my iPhone, I was finally able to successfully configure Face ID.

I don’t know for sure if that is the definitive way to “reset” Face ID, as some users reported success with rebooting their phones using the volume and side buttons. In any case, it appears that the TrueDepth camera that powers Apple’s Face ID technology just needed a kick in the pants.

Simplifying 3D Models

Have you ever used an application to generate a 3D model and ended up with an enormous .stl file? When I use HueForge, the resultant .stl files are usually around 125 MB. When I use TouchTerrain, I also end up with large 3D models. However, unnecessarily large models require more time for slicing and more storage space. Furthermore, if you plan to share your models on Thingiverse or other 3D model repositories, it may not be necessary to propagate such large models. Finally, what’s most important to me is that sometimes I want to edit models in Tinkercad, but 3D model imports are limited to files with 300,000 triangles or less. This is where mesh simplification comes in handy.

Mesh simplification, also known as mesh decimation or polygon reduction, is the process of reducing the number of polygons in a 3D model while maintaining as much of the original shape, appearance, and important features of the model as possible. This is similar in concept to compressing images and audio files where the intent is to reduce file size while preserving as much of the image or audio quality as possible. Mesh simplification is a feature of Blender, Meshmixer, MeshLab, SolidWorks, and other 3D modeling applications. But what if you don’t have any of these applications? While some of them are free to use, I haven’t wanted to install an application for the sole purpose of using its mesh simplification feature.

Fortunately I discovered 2 potential solutions that are both free and can run straight from your web browser. The first is 3DLess.com where you simply choose your file, specify the target number of vertices, and save your file. If you are concerned about privacy, a big benefit is that the processing happens locally on your web browser, meaning that your file is not uploaded. In my limited experience, this has not successfully reduced polygon counts or file sizes on the large .stl files that I’ve been trying to simplify. I assume I’m doing something wrong, so I mention this website in case others find success with it.

My preferred option is Fast Quadric Mesh Simplification. Simply choose your file, specify a % reduction, and click the “Simplify” button. I’ve found that it simplifies 125 MB HueForge files in a matter of seconds, and despite reducing polygons to 10% of its original size, I cannot visually tell the difference between the original and simplified models. Most importantly, this website has reduced models to the point where I can import them into Tinkercad and make simple modifications.

If you are looking for a free and easy solution to simplify your 3D models, I hope you are able to get great results with one of the above options. If you are aware other other websites that do something similar, let me know!

3D Modeling Earth’s Surface

Have you ever wanted to create a 3D model of a specific section of earth’s surface? I heard that it could be done using topographic data from the U.S. Geological Survey (USGS). So I asked ChatGPT to tell me step by step how to convert USGS topographic data into a 3D model in .stl format (see thread here). In response, ChatGPT told me that I need to:

1. Download USGS topographic data
2. Preprocess the data using GDAL to convert to ASCII Grid
3. Convert ASCII Grid to a 3D mesh using QGIS and the DEMto3D plugin
4. Optionally refine the 3D model in MeshLab
5. Save the final model in STL format

That sounded complex to me, as it involves applications and file formats that I have not previously worked with. Fortunately, I discovered that there is a much easier and faster way to get 3D models in .stl format. Simply use a website that provides this specific service. Here are 2 options:

Terrain2STL is a website that allows you to create .stl models of the surface of Earth. Its interface is pretty straightforward. You can zoom/drag to a location using Google Maps which defaults to Terrain View. You can also enter GPS coordinates (refer to this post for a refresher). Next, enter details about the width, height, and other details related to the dimensions of your desired model. Then adjust settings related to water and base height and finally export your model in .stl format. Terrain2STL has the advantage of its simplicity, but its main disadvantage is its resolution which is limited to 90 meters. Here is a screenshot of Terrain2STL (click to enlarge):

TouchTerrain is another website that allows you to create 3D printable terrain models. Similar to Terrain2STL, TouchTerrain allows you to zoom/drag to a location using Google Maps, but TouchTerrain also allows you to search for a place by its name, address, or GPS coordinates which can be very useful. TouchTerrain also allows you to choose from 3 different elevation data sources, each of which has varying resolution ranging from 10 to 2000 meters, depending on its purpose. For me the default USGS data source with 10 meter resolution produced a model with the level of detail that I was looking for. It also has inputs for 3D printer settings such as your build plate dimensions to help you determine the maximum size of your model. After inputting the relevant settings, generate and download your .stl model. Here is a screenshot of TouchTerrain (click to enlarge):

After you get your desired model from either Terrain2STL, TouchTerrain, or another method, you’ll be ready to slice and 3D print your model.

Gmail Plus Addressing and Dot Addressing

If you have a Gmail account, you can take advantage of a feature known as plus addressing. Plus addressing, as the name implies, allows you to append a plus sign, followed by any series of letters and/or numbers, to your email address. This can come in handy if you want to determine who is sharing your email address or if you want to create special rules to route emails to different folders in your inbox.

For example, if your email address is JohnSmith@gmail.com and you are signing up for an account at Company123, instead of providing your regular email address, you can provide JohnSmith+Company123@gmail.com. All emails with plus addressing will still be sent to JohnSmith@gmail.com. However, if you later receive spam emails with that plus address, it will be obvious that Company123 shared your email address with them.

As another example, you can use plus addressing along with Gmail filters to automatically apply labels or to categories your emails. Let’s say that you want to add your name to the email distribution list for your child’s elementary school. You could submit JohnSmith+Elementary@gmail.com as your email address and then create a filter (or category) as shown in the next 2 images.

Perhaps a lesser known but related feature is dot addressing in which you have the option to add periods anywhere in your email address. Periods in Gmail addresses are simply ignored, so you can add any permutation of periods such as John.Smith@gmail.com or J.o.h.n.S.m.i.t.h@gmail.com. The same filters and categories can be applied to your dot addresses.

Read more in this Gmail blog. Have you found other uses for Gmail plus addressing or dot addressing? If so, let me know how you’ve taken advantage of these features.

Eleven Table Tennis Player Statistics

Did you know that you can track your Eleven Table Tennis (ETT) player statistics online? The statistic that is likely of most interest to most ETT players is their Elo rating. Other statistics of interest may be their historical match results and recent wins and losses. While you can view these stats in the VR game itself, there are also 2 websites that I know of where you can browse these stats.

The first is the official Eleven VR website where you can view the global leaderboard and individual user profiles. Here’s my Eleven user profile: https://elevenvr.net/eleven/903406.

The second is 11ClubHouse which has most of the features of the official Eleven VR website but also features the ability for the community to comment on each player in terms of friendliness (via the Fair-play-o-meter) and a guestbook where players can leave feedback on other players. Here’s my 11ClubHouse user profile: https://11clubhouse.com/903406/.

As you can see, after seemingly hitting a plateau, a few days ago I just reached an Elo of 2100 for the first time ever. I don’t know if I just had some fluke victories or if I’m really improving, but to me the wins and losses and Elo ratings are less important than just playing and having fun. Hope to see you in ETT!