3D Printing 101 for Game Artists and Producers
 

I’ve taken an interest lately in 3D printing as a “new form of rendering” for 3D content.  
 

I realize I am not alone - just check out Bloomberg News or walk the floor at GDC and you’ll find lots of company. There’s a lot of hype (remember 3D TVs?)  And though there’s also a lot of information and experience out there already, it is pretty dizzying; you may not always want to believe what you hear from vendors, depending on the source and intensity of the hype.
 

Nevertheless, I recently took the plunge and went somewhat ‘up market’ in the desktop 3D printing world and got my own Formlabs Form1+ printer.  
 

It is pretty cool stuff, but with caveats that I’ll share along the way. The good news is there are a lot of choices and services you can utilize if you have a character or object you want printed.
 

Given the number of questions, pitfalls, and costs, I thought my personal trials could be great fodder for a Blog.  Especially considering how many incredible character artists I know out there who would not mind having some of their amazing work realized in physical form.
 

From there, who knows.  I’ll try to keep it organic and helpful. All comments are of course welcome.
 

Last thing before I dive in - Although 3D printing is relevant across a domain of content types (architecture, scientific visualization, mechanical assemblies, chemistry, and more), I have a great affinity for characters, so I thought I’d pursue a character-centric track to help keep things relevant and interesting.  But most everything I’ll cover below and in future installments will be general enough to apply to all of these domains.
 

With that said, here we go…
 

Installment One: Getting your Bearings

As mentioned above, this is going to be a brief pass over a number of global issues.  I’ll dive into much greater detail in installment two on Geometry prep in particular. But here’s a high level view of the topics I’ll be covering:

Your Geometry

As you may guess, just because it renders or moves in a game engine does not mean it will print.  Aesthetic design issues and physical size aside, today’s printers have a range of requirements that your character may not be quite ready for (or which may just exceed current state-of-the-art printer tech).  Different printers use different materials and print processes that are not as pain-free and magical as you may have heard… even though they are pretty flippin’ cool when you get right down to it.

At a high level, your character geometry needs to be topologically clean, comprise a closed volume (with caveats below), and resolvable into Triangles.  It also needs to be structurally sane.  Stuff that renders in the game or in beauty shots may very easily fall apart or collapse during a print.  Or simply fall over.  
 

Print nightmare Example (above): This Mech above is off-the-shelf from an on-line model shop.  While I would love for it to "just print", its geometry was not constructed with enough integrity to hold together.  Nor was the mesh "light tight" in all areas.  As such, getting a print of this complexity represents a sizeable about of remodeling work.  And even then, most 3D printers would struggle with the fine details.

But if you are building somewhat organic characters that deform in-game, and you have built them with resolution-independence in mind, you may have a continuous mesh that is dangerously close to being printable (and cool). The good news about 3D printing is that you can go crazy (er) with geometric details, assuming your tool of choice will take you there.  Think upwards of 500K-1M polys (go Zbrush!)  I’ll dive into more geometry details in my next installment.

28K Triangles... lots of room to go up, especially for surface details.  - Artist: Shawn Nelson

“Tiki contemplating apple contemplating Tiki”

Regarding volume, since a large component of price is based on material used, you may find that hollowing your character becomes necessary to control costs and reduce print times.  You still need to maintain closed-mesh topology, but you’d need to introduce an inner wall to your character and ‘escape holes’ to let air and material filter out.  More on hollowing below in the section on Size - and in my next installment.  

But definitely keep volume and hollowing in mind, because it is potentially the hidden gotcha in the mix.

Quality
 

No doubt as an artist or game developer. you have become accustomed to pushing the limits on quality as far as you can, to realize your creative vision.  When it comes to ‘accessible’ 3D Printing (based on price), however, we are still in the “Playstation 1/2” Era.  Meaning: at-home printers that are affordable to hobbyists are still pretty modest on the quality scale.  You can get amazing stuff from the Pros (and you may very well want to do that), but what you can “print at home” or via a 1-off printer service has limitations you should know about.  Here are a few:
 

Here's a close-up of the teeth from that same print.  Not bad.
 

Price
 

Having a printed version of your characters is potentially very cool, but many folks are in for a sticker shock when they first dive in to this domain.  
 

The reality is that 3D printed characters of even modestly high quality and larger size (6-12 inches tall) are expensive.  We are talking potentially over $50 and/or days or weeks of production time from a service shop.
 

Here are three main approaches to pricing a print:
 

Home Printing: If you own a printer and are willing to print smaller (under 6 inches), you can bring that price down significantly ($1-$25 range).  But even raw materials tend to add up, depending on your quality requirements and printer type (and the number of failed print attempts you may encounter!).
 

Service Bureau: If you outsource your printing to a general service bureau, you can expect to wait perhaps a week or more.  And even a small sized character print can run you in the $25-$50 range.  But get ready for surprises if your character has issues.  Those prices can go up if a provider needs to fix things for you. Or, a more hands-off service bureau might just print “as is” and what you get is what you get.
 

Pro Shop: If you want it ‘tomorrow’ and go with a high-end print shop, that price can climb into the hundreds of dollars ($50-$500), but you will get a full service experience including help with geometry tweaks as necessary, and final print cleanup.

Quantity

Regarding quantity - If you only need one or two copies, and you are happy with something that will fit easily in a 12x12x12 inch space - 3D printing is probably the way to go.  Especially if you want to prototype before you move to larger production.  

Otherwise, if you are looking for a cheap way to mass produce parts or characters, more tried-and-true commercial solutions like injection molding are the way to go.  You may still consider 3D printing as a means of getting your original mold, but it will not likely be the path you take to produce more than a few copies.

Time

If you are unlucky enough to remembering day long rendering times for a basic image, you may have a sense of what it takes to print a character.  The process is very cool to watch for about the first 20 minutes, but then you pretty much want to leave it alone and get back to your day job.  If you are sending your print off to a print shop or service, you are still likely in for a bit of a delay - days or weeks. (Unless you go with a top notch print house that turns stuff around in days rather than weeks).  Most of the time, a print at home will be your fastest option (though quality becomes an issue depending on your printer).  Followed by a top-end shop.  At the moment, most service bureaus turn prints around in a week or so (including shipping), but it could be longer.  It really depends on the issues your character may have during the process, and how busy that particular service is for the printer assigned to your character.  
 

If timing (or learning from a short feedback loop) is paramount, you will want to go with a high-end service print shop or your own printer at home, at least for now.

Size & Hollowing

A 12 inch character on your desktop would be pretty cool.  But most low-mid range printer build volumes cannot accommodate a character over 6 inches.   

So the first thing out of the gates is knowing roughly how big an affordable build volume might be.  At home ‘affordable’ printers generally top out around 300 mm for the largest dimension (Z, up).   With x and y dimensions falling well below that (125mm).  That’s just under a 12 inch character, which is pretty big in the world of 3D prints (and you are probably talking hundreds of dollars, depending on your choices of services and printers).  
 

Pro-level printers go up from there, with the xy dimensions (the build platform), growing quite a bit, which is especially helpful for architectural prints.

So printing smaller may not be your first choice, but something around 2-3 inches is not a bad place to start.

One other issue to consider, relative to the hollowing topic mentioned above, is that as you scale down your character to fit a price or build volume, the THINNESS of what was an ok section of your character can enter the danger zone.  Sadly, digital models are not trivially scalable in print!  

This scan of a lower jaw & teeth needed to be holloed out for my printer to help save resin and improve final print quality. (Some printer software automatically provide non-solid fill as part of their pre-print process)

For fingers and legs, etc, you can go pretty small depending on the printer you are using.  Maybe just a few mm thick, if the appendage is NOT hollow.  And as for explicit hollowing of parts.. it becomes much less of an issue as you approach figurine sized character.  Because price drops dramatically with smaller sizes, you have the option of just leaving your character fully solid and saving headaches on remodeling costs.  Double bonus!

All said, I still plan to take on a larger-scale character print, though I’ll probably attempt to do that in pieces and assemble/glue after the fact. Once I get there, I cover that topic explicitly in a future installment.

Pose and Structural Integrity
 

This is one of those creative compromise topics that is directly related to how much pain you may want to take on to realize the true vision you have for your character.  Thin, wiley appendages or borg-like wires and tubes could drive you and your printer (or your service provider) to an early grave.  But more power to you.  I personally would like to see the limits totally pushed on this kind of thing.  But starting out, you may want to pick a character that is a bit more structurally sound and/or a pose that stays far away from the classic “T” position.  (arms and fingers tucked - thick appendages, solid stance or planned attached base).
 

Doing otherwise is fine and possible, but may result in more print failures along the road to wisdom and the material costs can pile up along the way.  Again - if you go with a high-end print shop they may be able to help you avoid some pitfalls themselves or give you some guidance on choosing a different pose, or dropping some crazy antennae attachment for your alien.  Just be aware and ramp up gradually if you can stand it.

Wrap Up

That’s just a brief intro.  If you are not totally turned off, check on my next installment for more details on geometry prep.  Chances are you are already close with your current character.
 

END INSTALLMENT ONE