Learn What A Gaussian Splat Is, Then Make One

October 31, 2025 by Donald Papp 16 Comments

Gaussian Splats is a term you have likely come across, probably in relation to 3D scenery. But what are they, exactly? This blog post explains precisely that in no time at all, complete with great interactive examples and highlights of their strengths and relative weaknesses.

Gaussian splats excel at making colorful, organic subject matter look great.

Gaussian splats are a lot like point clouds, except the points are each differently-shaped “splats” of color, arranged in such a way that the resulting 3D scene looks fantastic — photorealistic, even — from any angle.

All of the real work is in the initial setup of the splats into the scene. Once that work is done, viewing is the easy part. Not only are the resulting file sizes of the scenes small, but rendering is computationally simple.

There are a few pros and cons to gaussian splats compared to 3D meshes, but in general they look stunning for any kind of colorful, organic scene. So how does one go about making or using them?

That’s where the second half of the post comes in handy. It turns out that making your own gaussian splats is simply a matter of combining high-quality photos with the right software. In that sense, it has a lot in common with photogrammetry.

Even early on, gaussian splats were notable for their high realism. And since this space has more than its share of lateral-thinkers, the novel concept of splats being neither pixels nor voxels has led some enterprising folks to try to apply the concept to 3D printing.

Nanochat Lets You Build Your Own Hackable LLM

October 20, 2025 by Donald Papp 23 Comments

Few people know LLMs (Large Language Models) as thoroughly as [Andrej Karpathy], and luckily for us all he expresses that in useful open-source projects. His latest is nanochat, which he bills as a way to create “the best ChatGPT $100 can buy”.

What is it, exactly? nanochat in a minimal and hackable software project — encapsulated in a single speedrun.sh script — for creating a simple ChatGPT clone from scratch, including web interface. The codebase is about 8,000 lines of clean, readable code with minimal dependencies, making every single part of the process accessible to be tampered with.

An accessible, end-to-end codebase for creating a simple ChatGPT clone makes every part of the process hackable.

The $100 is the cost of doing the computational grunt work of creating the model, which takes about 4 hours on a single NVIDIA 8XH100 GPU node. The result is a 1.9 billion parameter micro-model, trained on some 38 billion tokens from an open dataset. This model is, as [Andrej] describes in his announcement on X, a “little ChatGPT clone you can sort of talk to, and which can write stories/poems, answer simple questions.” A walk-through of what that whole process looks like makes it as easy as possible to get started.

Unsurprisingly, a mere $100 doesn’t create a meaningful competitor to modern commercial offerings. However, significant improvements can be had by scaling up the process. A $1,000 version (detailed here) is far more coherent and capable; able to solve simple math or coding problems and take multiple-choice tests.

[Andrej Karpathy]’s work lends itself well to modification and experimentation, and we’re sure this tool will be no exception. His past work includes a method of training a GPT-2 LLM using only pure C code, and years ago we saw his work on a character-based Recurrent Neural Network (mis)used to generate baroque music by cleverly representing MIDI events as text.

2025 Component Abuse Challenge: Conductive Filament Makes A Meltable Fuse

October 19, 2025 by Donald Papp 13 Comments

Everything is a fuse if you run enough current through it. Or at least [JohnsonFarms.us] seems to think so, which has led him to design 3D-printed fuses made from conductive PLA filament.

Conductive filament is a meltable resistor, which, if one squints hard enough, is basically a fuse.

In theory a 3D printed fuse works the same as a normal one: excessive current draw will cause the conductive plastic to briefly become a heater, causing it to self-destruct and break the electrical connection. There’s a risk of melted plastic and perhaps a nonzero combustion risk, but [JohnsonFarms.us] is less interested in whether this is a good idea and more interested in whether it can work at all, and with what degree of predictability and/or regret.

His experiments so far show that printed fuses are essentially meltable resistors with values between 300 Ω and 1250 Ω, depending on shape. What it takes to bring those to roughly 60 °C, where PLA softens, and around 150 °C, where PLA melts, is next on the to-do list.

Whatever conclusions are reached, it is interesting to think of conductive filament as a meltable resistor, and ponder what unusual applications that might allow.

Most conductive filaments have high resistance, but not all. Some, like Electrifi by Multi3D, have extremely low resistance and were used in a project that made 3d-printed logic gates.

Bit-banged 100 MBit/s Ethernet Transmission On Raspberry Pi Pico

October 18, 2025 by Donald Papp 25 Comments

The Raspberry Pi Pico is a very capable board, but it’s still a surprise to see bit-banged 100 MBit/s Fast Ethernet implemented on one. [Steve]’s Pico-100BASE-TX library allows an RP2040 (or RP2350) microcontroller to stream data at roughly 11 Mbyte/s, enough to implement 100 MBit/s Fast Ethernet transmission.

We’ve seen 10BASE-T implemented on a Pico, but it takes a lot more than just shoveling bits faster to get 100BASE-T working. 10BASE-T uses two voltage levels and Manchester encoding, but 100BASE-T uses three voltage levels, which [Steve] cleverly implemented on the Pico with two GPIOs, and far more complex encoding. Check out the repository’s README for details as well as a couple example applications.

[Steve] tells us that to the best of his knowledge, this is the first bit-banged 100 MBit/s Ethernet implementation using a microcontroller. It’s transmit-only — reception being an entirely different beast — but it’s possible some enterprising soul might find a solution. If you do, be sure to let us know all about it!

PVC Pipe Structure Design That Skips Additional Hardware

October 12, 2025 by Donald Papp 47 Comments

[Baptiste Marx] shares his take on designing emergency structures using PVC pipe in a way that requires an absolute minimum of added parts. CINTRE (French, English coverage article here) is his collection of joint designs, with examples of how they can be worked into a variety of structures.

Basic joints have many different applications.

PVC pipe is inexpensive, widely available, and can often be salvaged in useful quantities even in disaster areas because of its wide use in plumbing and as conduits in construction. It can be cut with simple tools, and once softened with heat, it can be re-formed easily.

What is really clever about [Baptiste]’s designs is that there is little need for external fasteners or hardware. Cable ties are all that’s required to provide the structural element of many things. Two sawhorse-like assemblies, combined with a flat surface, make up a table, for example.

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The Subtle Art Of Letterform Design

October 12, 2025 by Donald Papp 13 Comments

Typeface (such as Times New Roman) refers to the design that gives a set of letters, numbers, and symbols their signature “look”. Font, on the other hand, is a specific implementation of a typeface, for example, Times New Roman Italic 12 pt.

‘Q’ is a counterpoint to the idea that typography is just one fussy detail after another.

Right about this point, some of you are nodding along and perhaps thinking “oh, that’s interesting,” while the rest of you are already hovering over your browser’s Back button. If you’re one of the former, you may be interested in checking out the (sort of) interactive tour of typography design elements by the Ohno Type School, a small group that loves design.

On one hand, letters are simple and readily recognizable symbols. But at the same time, their simplicity puts a lot of weight on seemingly minor elements. Small changes can have a big visual impact. The tour lays bare answers to questions such as: What is the optimal parting of the cheeks of a capital ‘B’? At what height should the crossbar on an ‘A’ sit, and why does it look so weird if done incorrectly? And yet, the tail of a ‘Q’ can be just about anything? How and why does an ‘H’ define the spacing of the entire typeface? All these (and more) are laid bare.

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A Deep Dive Into The Coolness That Was CRT Projectors

October 11, 2025 by Donald Papp 23 Comments

CRT monitors: there’s nothing quite like ’em. But did you know that video projectors used to use CRTs? A trio of monochrome CRTs, in fact: one for each color; red, green, and blue. By their powers combined, these monsters were capable of fantastic resolution and image quality. Despite being nowhere near as bright as modern projectors, after being properly set up, [Technology Connections] says it’s still one of the best projected images he has seen outside of a movie theatre.

After a twenty-minute startup to reach thermal equilibrium, one can settle down with a chunky service manual for a ponderous calibration process involving an enormous remote control. The reward is a fantastic (albeit brightness-limited) picture.

Still, these projectors had drawbacks. They were limited in brightness, of course. But they were also complex, labor-intensive beasts to set up and calibrate. On the other hand, at least they were heavy.

[Technology Connections] gives us a good look at the Sony VPH-D50HT Mark II CRT Projector in its tri-lobed, liquid-cooled glory. This model is a relic by today’s standards, but natively supports 1080i via component video input and even preserves image quality and resolution by reshaping the image in each CRT to perform things like keystone correction, thus compensating for projection angle right at the source. Being an analog device, there is no hint of screen door effect or any other digital artifact. The picture is just there, limited only by the specks of phosphor on the face of each tube.

Converging and calibrating three separate projectors really was a nontrivial undertaking. There are some similarities to the big screen rear-projection TVs of the 90s and early 2000s (which were then displaced by plasma and flat-panel LCD displays). Unlike enclosed rear-projection TVs, the screen for projectors was not fixed, which meant all that calibration needed to be done on-site. A walkthrough of what that process was like — done with the help of many test patterns and a remote control that is as monstrous as it is confusing — starts at 15:35 in the video below.

Like rear-projection TVs, these projectors were displaced by newer technologies that were lighter, brighter, and easier to use. Still, just like other CRT displays, there was nothing quite like them. And if you find esoteric projector technologies intriguing, we have a feeling you will love the Eidophor.

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