Tag Archives: miniature

Anatomy of A Remix

remix

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One of the highlights from World Maker Faire 2013 in NYC was meeting Thingiverse All-Star cerebus333. He’s friendly, engaging, and incredibly prolific; I can’t recall a week’s recent passing where he hasn’t posted at least one new model to his collection.

I was honored to take home an autographed Rock Frog from Cerebus’ collection, and I promised him that I’d take a shot at remixing his work when I got back home. Here’s the original model, standing about 7 inches tall.

original

Cerebus has designed the Rock Frog to print reliably on an FDM printer, and print reliably it does: the mesh is manifold and it’s physically quite stable on the build platform. My plan is to re-pose the original and turn it into something usable as an RPG elemental or golem miniature, and that’s going to require some geometry edits.

Step 1

Cerebus designed the Rock Frog’s knuckles to lay flat on the printing bed. If they’re going to potentially be raised up in the air they’ll need to look more like fingers. I’ll delete the old flat surface and replace it with some vaguely-knucklelike ridges. A little sculpting here and there and we’ve got something that looks good enough for now– my experience with 3D printing tells me that much more detail here isn’t going to print at this scale so there’s not much point in overworking the model.

Note the strange triangulation in the sole of the foot, because I’ll fix that in step 2.

I’ve split him in half down the YZ axis so I only have to fix one hand before mirroring and rejoining the model.

edited fist

Step 2

The foot geometry is fine for printing, but not so good for deformations. This should be a straightforward fix, and afterwards Rock Frog will be able to put some weight on the ball of his foot.

fixed feet

Step 3

Rock Frog’s mouth is closed in the original. I’ll find the inside crease of his mouth, split the geometry, and then open up his mouth. A note for folks not used to working with character models; it’s generally easiest to work on one half of a model and then mirror it, which is why the original Rock Frog has been split down the middle here.

mouth

Step 4

Bipedal 3d characters are usually modeled in T-Pose, with arms outstretched. This pose helps when assigning weights to vertices, step one in rigging a character. I’m not going to invest a lot of time in a full animation rig here, just enough to intuitively bend Rock Frog at his joints.

Rock Frog’s legs are already in a good position for vertex assignment, so no adjustments need be done there. Once I’ve got him in T-pose I’ll inspect the mesh one more time to make sure the mesh is closed and manifold.

back

If you’d like to pose Rock Frog on your own, go ahead and download the t-posed model.

Step 5

I reach way back into the mists of time for inspiration, back to a time when Xiao Zheng was a fifth grader surreptitiously poring over the 1st Edition AD&D monster Manual under the covers. I move some joints around here and there until Rock Frog more or less resembles David C. Sutherland III’s classic drawing of an earth elemental, with allowances made for the gravity-plagued medium of supportless FDM printing.

The posing created some self-intersecting geometry where I didn’t bother to weight the vertices properly. Bad mojo. I can easily fix this by painting the vertices with a smoothing algorithm, but doing so while the model’s rigged to joints can be slow and produce unpredicatble results.

At this point it makes sense for me to detach the geometry from its joints, freezing Rock Frog in this position. I’ll save a version of the rigged model in case I want to re-pose him later.

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And now a test print. Almost everything prints OK, but the heel of his right fist hangs out in space just a bit too much. Frankly I should have seen this coming. Part of the problem is that I’m printing at a .3mm layer height for the test, but there’s just too much overhang there even with a higher-resolution print.

back

The model’s now detached from its joint system, so if I’m to edit that fist I have to do it without the benefit of a weighted joint system. This is a small tweak, so I just throw a lattice around the fist and forearm instead of backing up to the beginning of step 5.

lattice fix

The fist on the second print looks much better, so I’ll go back and add some aesthetic tweaks. I’d like to roughen up the surface with some stony protrusions. Much of this can be done with Maya’s poly sculpting tools, but I add some nicely geometric gems for contrast too.

gems

The gems stuck in the Rock Frog’s back are easy to model but they don’t retain their sharp geometry in the final print. I’d like to see how this prints at a higher resolution.

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This model and others like it are of course available for free download in The Forge. This post is the first in my series of Maker Faire Gems, wherein I’ll be blogging interesting stuff I discovered this year that might have slipped through the bigger outlets’ coverage. #staytuned

Quality Control

I recently released a Magic: The Gathering Snake Token into the wild, but many iterations of the model got left on the scrap heap before the final slithered off the build platform.

Here’s one that made it all the way to the light tent before I realized the many problems it had. Sometimes you don’t see all the problems until you really dig into a macro photograph.

Snake QC fail

  • overhang: violations of the 45° rule. Not terrible on this one.
  • scrubbing: the model’s too thin here. ABS or a cooling fan might help.
  • nickeling: not enough geometry to make a smooth curve in the body
  • schmutz: really should have filed this off before painting.
  • I can forgive a little bit of overhang on a model. Sooner or later some 3d printer manufacturer’s going to lick that problem for us. Scrubbing is a technical issue too, and schmutz removal is a time-honored pre-photography process that I was just too lazy or preoccupied to do on this model.

    It is the nickeling that I shan’t abide.

    I come to 3D modelling from a video games background, where realtime constraints force model efficiency. When I was a lad with an onion tied to my belt, which was the style at the time, we designed characters with 150 triangles and we liked it that way.

    So every now and then I forget that I’m not living in 1997 anymore and I can be a little more luxurious with the poly count. It still feels dirty though.

    So Ms. Cobra went back into the Forge, got subdivided again, re-posed, edited, tweaked, and was reborn as the final product you saw a day or two ago.

MTG Zombie Token

MTG Zombie Token

downloadWhen looms a medieval zombie apocalypse (which, frankly, happens every time the local necromancer goes for a stroll) it’s not the lords and ladies, safely ensconced behind thick citadel walls and rows of nervous archers who get chomped; if serf’s up for Jack and Jill mudgrubber they’re crudités for Zed anon.

With a model this small, it’s all about pose. How do you communicate shambling corpse with the broadest strokes, while keeping overhangs to a minimum?

Some details unfortunately get lost in the printing, like this lovely compound tibial fracture.

I’m a little disappointed in the resolution of the print. Even at .1mm layer height the finer details of Zed’s leg get lost, as does his partially-revealed skull. My understanding is that several key powder printing patents expire in 2014, so perhaps by then we’ll be able to print this zombie with all his putrid details intact.

At that point I’ll have to go back and add some facial features, because for now Zed doesn’t have a nose or clearly defined mouth.

Snakes on an XY Plane

printrbot calibration fails

Snake tokens in Magic: The Gathering are generated by many cards, including but not limited to ye olde Snake Pit, Endless Swarm, and of course many of the Orochi cards. Much MTG Snake card art eschews long and slithery reptiles in favor of four-armed humanoid ophidians, but for this 3d token I decided to go all Rikki Tikki Tavi and model a cobra instead.

downloadMy original plan was to save myself some time by unrwapping the Ouroboros and giving her a cobra cowl, but the more I studied the anatomy connecting the hood to the head the more I realized that wasn’t going to work. After a few false starts I just ditched the original head and started fresh.

There are two versions of this snake in the archive. snake_resin was designed specifically for the mUVe1 resin-based printer and has an inconspicuous resin drain inside the 正 that lurks in the model’s base. It’ll still print on a filament printer though. snake_fdm patches the hole for use on filament deposition printers like the Replicator or Printrbot series.

The model in this photo is printed on a Replicator1 at .1mm layer height with black PLA (205°) and then spray-painted green. Usually I’m printing at .18mm, but I recently got my HBP bed leveled so nicely I thought I’d try printing at highter resolution. If you’ve got yourself a HBP, set it to 60°, folks. For great justice.

As always, you can grab this model for free from the Miniatures section of The Forge. Like the MTG rat pack, I could in theory pose this cobra a half-dozen ways, so #staytuned: there may be another MTG snake token or two slithering your way in the near future.