Every once in a while, someone stumbles into subsurface 3D crystal engraving by accident. That’s exactly what happened when Michael from the LaserEngraving911 YouTube channel accidentally created a subsurface effect with his UV laser. And eventually, this sparked a lot of questions from his audience:
- How does subsurface laser engraving actually work?
- What kind of laser do you need to make a 3D crystal?
- Is there any difference between UV and green beam for deep 3D engraving?
- How exactly does AI turn a flat photo into a 3D model that can be burned inside a crystal?
Michael invited me onto his channel to dig into those questions and get a proper grasp of 3D Laser engraving. This write up serves as a structured breakdown of that conversation with a detailed explanation of what subsurface engraving is, why green beam lasers are still the benchmark for 3D crystals, and how software like Cockpit3D and portable machines like JetMini fit into the picture.
If you’ve ever looked at a 3D crystal and wondered, “How on earth did they put that picture inside there and that too in 3D?”, this is for you.
What Is Subsurface 3D Crystal Engraving?
Let's start with the very basics. Most people are familiar with surface engraving, where you blast or mark the top layer of glass, wood, metal, or acrylic.
But subsurface engraving is different.
Here, instead of burning the surface, the laser focuses inside a transparent material, which is usually a high-quality optic crystal, and creates tiny micro-fractures at very precise points below the surface.
It is easier to understand if you think of it like:
- Using a magnifying glass to focus sunlight on a leaf
- But instead of sunlight, you’re using a laser
- Instead of burning the leaf, you’re focusing the energy at a point inside the crystal
When all those focal points are stacked together, hundreds of thousands or even millions of them together form the appearance of a 3D model of the image floating in the crystal.
In the industry, we often refer to these points as voxels or a point cloud.
How Subsurface Engraving Differs from Surface Engraving
With a typical laser engraver:
- You have just one main focal plane,which is the surface of the material.
- You engrave in 2D that is either a line art graphic, logo, or photo
- Motion is usually in X and Y, with Z used just to set the focus distance
Whereas with subsurface engraving:
- You’re working in true 3D space
- The focal point is controlled on the X, Y, and Z axes
- The laser is directed inside the crystal to a specific point, fired for a fraction of a second, and then moved to the next point and so on.
Initially, when we started in this space, our machines were hitting around 100 points per second. That felt really fast at the time. Today, modern systems reach thousands of points per second. But speed is not only about the laser, it also depends on the galvos and how efficiently the path is planned through 3D space.
The end result is the same concept as an old dot matrix printer, where many small dots, placed correctly, add up to a complete image. In this case, the dots are micro-fractures suspended inside the crystal.
Why Green Beam (532 nm) Is Still the Laser of Choice for sub surface laser engraving
Michael’s accidental experiment with a UV laser raised a really good question, which is
Can you do 3D subsurface engraving with UV?
The short answer to this question is yes, to a degree. But there’s a really good reason why most professional 3D crystal systems still rely on green beam (532 nm) YAG lasers.
Here’s a breakdown of those reasons.
Wavelength and History
- Subsurface engraving actually began with 1064 nm infrared lasers, especially for industrial applications like embedding tracking code inside bottles, helping manufacturers track where their product ended up.
- Over time, the industry moved to a 532 nm green beam, which is essentially 1064 nm converted through a crystal to green.
The green beam 532 nm has now become the standard for 3D crystal engraving because of several reasons, and some of them are:
- It delivers strong, consistent energy inside the crystal
- It works well with larger fields of view
- It produces bright, stable micro-fractures that are best suitable for deep 3D images.
UV vs Green Beam in Practice
UV lasers are fantastic tools for many materials and are a great option for at-surface or near-surface engravings. You can even push them into shallow subsurface work.
But for deep 3D engraving inside optic crystal, the green beam still has the edge in three big areas:
- Depth and clarity
Green beam systems have the ability to maintain brightness and clarity deeper inside the block. - Field of view
Green beam lasers cover larger sizes of glass - Speed with 3D dense files
If you prefer high definition and dense texture-based 3D point clouds, then green beam setups are the perfect choice as they are typically faster and more stable.
That’s why, even though UV is improving and has its place, green beam is still the laser of choice when your main goal is high-quality 3D crystal engraving at production speed for business usage.
How AI and Cockpit3D Turn 2D Photos into 3D Point Clouds
Early on, the only way possible to create a true 3D model of a person was to:
- Have them sit right in front of a multi-camera rig or 3D scanner
- Capture depth and texture from multiple angles of the person's face.
- Use that 3D model as the base for the point cloud.
It worked for sure, but was limited in several ways. People at tourist locations weren’t always “camera ready”, and the main problem was that many of our customers wanted to create crystals as gifts from existing photos.
The big shift came when we moved from:
• 3D scanners + in-person capture
to
• 2D photos + 3D modeling + AI
Manual 3D Modeling Era
Understanding the limitations of what we had, we built a process where:
- Customers had the option to upload a regular photo
- 3D artists manually modelled the subject in 3D
- The 3D model was textured carefully without losing a single detail of the image and then converted to a point cloud for engraving.
At one point, this process that we came up with involved over 200 artists working on photos from various locations around the world. It worked well, but was time-consuming. It took around an hour per person for the detailed work to be done.
AI-Assisted Era
Over the last few years, we have been able to make significant improvements. What paved the way to these improvements is a combination of:
- Thousands of meticulously created 3D models
- Permission-based photo datasets
- Internal AI pipelines
And this has allowed us to train models that can:
- Take any 2D photo
- Automatically generate a 3D base model that’s about 80% complete
- Our Human artists step in and handle the last 20% of the fine-tuning, like fixing the hair, glasses, noses, and other small details that the AI can’t get perfectly on its own.
The key lesson we learned along the way:
The AI image output that looks amazing on a computer screen doesn’t always engrave the same way in the crystal.
The real test is when you remove the texture and burn the point cloud in crystal. For example, if noses look flat, hands are melted together, or the glasses and eye sockets are wrong, customers notice immediately.
So we decided to use AI as a powerful assistant, but still keep human oversight to ensure perfection in terms of quality. This is essential for us to maintain clients like Disney that need fast turn around of high quality pointclouds that are accurate.
The result is a pipeline where:
- Our Cockpit3D software can convert photos to engravable 3D point clouds in minutes.
- Laser operators around the world now achieve consistent output
- Customers get “CinematicHD” style engraving with fine detail and realistic shading, capturing the true essence of their pictures.
Why Optic Crystal and Not Acrylic Is Used
A common question that we come across is:
“Can I just use acrylic instead of crystal?”
For subsurface 3D engraving, the short answer is: it’s not ideal.
Optic crystal has a few advantages:
- Clarity and absence of tint
- Standard glass often has a greenish tint on the edges.
- Optic crystal is ultra-clear, which makes it an ideal choice as the engraving appears sharper and more neutral.
- Behaviour under laser stress
- Optic crystal forms clean micro-fractures at the focal point.
- Acrylic tends to melt around the point rather than cracking cleanly, which reduces resolution and produces less defined dots. This reduces the sharpness of the image.
- Surface polish and warp
- High-quality optic crystal is cut and polished so that the surfaces are extremely flat and free from warping, making it easier to burn on.
- With warped surfaces, the laser can refract in unpredictable ways before it reaches the focal point inside, causing missed or inconsistent dots.
The value in a 3D crystal piece is not just the raw material itself. It’s what the laser does to it.
Here we are transforming a relatively low-cost, stable material into something emotionally significant and visually striking.
Production Speed: From 45 Minutes to 45 Seconds
In the early days, a small keychain could take:
45 minutes to an hour just to engrave, and even then, the point densities were relatively low.
Today, with optimized:
- Point spacing
- Laser pathing
- Hardware
- AI-assisted file creation
The same size keychain, with a dense, high-quality point cloud, can be produced in around 45 seconds to 1.5 minutes, depending on the image content.
Important factors affecting burn time:
Brightness of the image
- White areas = more points (inverse of inkjet printing).
- Dark areas = fewer points.
Point spacing (effective “DPI” in 3D)
- Tight spacing,approximately close to 0.06–0.07 mm, gives rich detail but requires careful testing to avoid cracking.
- Wider spacing is faster but looks less sharp.
Number of layers
- You can burn fewer layers for a lighter depth, or more layers for a very solid and volumetric look.
- More layers = more time.
Portable Event Machines and Real-World ROI
One of the bottlenecks that we had to face in the early years of SSLE was:
- High machine cost (well into six figures)
- Large, heavy systems that had to stay in one location and took a lot of effort to move around.
- Long turnarounds where we had to say“come back later or tomorrow.”
That pushed us to develop portable systems like the JetMini series, a compact green-beam subsurface laser machine designed to:
- Travel in a protective rolling case, making it portable.
- Be easily set up at festivals, malls, trade shows, school fundraisers, and corporate events
- Produce keychains in under a minute and larger crystals in under 30 minutes, massively reducing the turnaround time.
Real-world examples from the interview:
- One operator recouped their machine investment in 27 days, mainly through Christmas sales.
- Another did a 10-day festival and averaged around $2,900 per day in sales, totalling roughly $29,000 in that single run.
The business model works well because:
- The raw material, which is the optic crystal, does not expire like food, cosmetics or other products.
- The perceived value comes from personalization, speed, and emotional impact.
- The machine can be used both for on-site events and for online orders.
Starting a 3D Crystal Business the Right Way
The truth is, a 3D crystal machine, no matter how advanced, does not sell by itself.
In the interview, we spent time talking about the real work:
- Doing market research before you even buy the machine is equally important to reach your profit goals, along with the advanced machine.
- Researching and finding events, venues, and fundraisers where your product fit.
- Hustling to build relationships with schools, malls, tourist attractions, and event organizers.
- Managing your time between weekday fundraisers and weekend festivals.
A few practical ideas that came up:
School fundraisers
- It is a great idea to put up displays in daycare centers and schools where parents physically come in to pick up their children.
- Offer a portion of sales back to the school, like around 15% or so, which can beat typical bake sale revenue and help you get invited back regularly.
Local events and markets
- Fairs, festivals, Christmas markets, and tourist spots can serve as an ideal choice for impulse and emotional purchases.
Online + offline omni-channel
- Pair a portable machine with a strong online presence so you can capture orders year-round.
A realistic mindset helps!
Some people may pay off the machine in 30 to 90 days. Others might take a year. The point is that the business starts before the machine arrives. It truly starts when you start doing the groundwork.
This interview also appears on our 3DCrystal.com youtube channel where you can find plenty more educational videos on sub-surface laser engraving: https://youtu.be/eXfUZvXJg-k