Shielding Backers From Fugliness

First, you should totally join The Horde to keep up-to-date on the comings and goings at Zheng Labs.

The Horde is a relatively low-volume, high signal, low-noise mailing list, maybe one email a month with a digest of blog posts and whatever other interesting 3D printing scrapple I can sweep off the abattoir floor for you. Also: Horde members will be the first to hear about Zheng3 Kickstarter #2.

And now on to show-booty-bidness: I’ve been hindered by a repetitive stress injury for the last week or so, a remnant of my mouse-using days that flares up if I do too much high-detail work without resting.

Creating the selection masks for the parade armor’s cuirass is exacting work, and interesting enough that I postpone my RSI breaks for JUST ONE MORE EDGE LOOP AND THEN I’LL STOP I PROMISE.

Sometimes intense focus is a recipe for injury, and frankly I should know better by this point in my career. A fortnight ago the pain finally got bad enough to force me away from the Wacom tablet for a while.

But in this business you hip, hop, the hippie, the hippie, to the hip hip-hop and you don’t stop. You. Do. Not. Stop, not while you’ve got backer rewards to print and shipping infrastructure to be laid down.

So with NSAIDs and ice packs and my good wrist I kept going on the boring stuff, and finally this morning the wrist has healed enough to send me back to creative work.

I’m printing a suit of field plate for a backer right now and I’m displeased with the shield’s attachment point. My original design was good enough to be photographed (you don’t see the attachment in any of the photographs I’ve released so far) but now that I’m sending a piece of physical art out to a backer I can’t bear to let my name be attached to this fugliness:

fugly shield

That’s the mortise where a forearm cuff snaps into the shield. There are two problems with it: first, it violates the 45° rule, which means the printer can’t handle the slope as it builds up layer by layer.

Second, the mortise is too wide for the printer to bridge easily once it hits that 90° bend at the top.

This needs a few little geometry edits, like so:

shield geometry edits

First, make that slope a little less than 45 degrees. Second, add a little peak to the mortise so that the printer can handle the bridge a little bit at a time. Note that the shield prints upside-down: sometimes the best orientation for printing isn’t the most intuitive way to design a model.

A shield can take a while to print, so I’ll cut down the geometry and try it with a test piece first. This piece is skinny and likely to fall over while it’s printing, so I extruded a little brim on the bottom to keep it stable.

shield test

Fantastico! This works. The squiggly deformations on the left side of the test print tell me I have a little bit of temperature fine-tuning to do with this roll of filament, but I think I’m ready to try a final print of the shield:

shield fixed

I’ll incorporate the new shield attachment into both the field plate and the parade armor.

What do you think?