Abstract

Deep in the Himalayas of the filament cabinet, a new species has evolved. Meet the Otto Yeti - an Otto that traded its sleek plastic shell for a thick protective coat of 3D-printed fur.

Otto Yeti is an easy‑to‑print accessory that gives your HP Robots Otto the look of a hairy Yeti!

The Otto Yeti is fully compatible with the Otto modular system.

Preparing the print

Print it with white PLA for that classic Yeti look.

Typical parameters are: no supports, layer height =0.2mm and infill >=15%.

Layer height is important in this model, in this type of hairy models hair size correlates with layer height. The default model design parameters works fine with layer heights of 0.2mm. Download the OpenSCAD file for fine tuning your model.  Here's a GIF of the hairs being printed!

Let the heated bed cool down before removing the part, hairs are fragile and could break, damaging the part.

Post-processing

This is how the print part should look like after removing it from the printer.

Now its time to cut the frame!

Gently with a sizor or cutting pliers remove the frame piece by piece. Start by removing the frame corners. 

And then proceed to the hair support.

Now that the frame is removed we can start grooming!

Grooming your Yeti

For grooming your Yeti use this kid-friendly method, you will need a standard hair dryer.

An hair dryer has a wider, gentler flow, which is actually better for getting that consistent "fluffy" look and it's safer than an heat gun. A hair dryer typically tops out around 60°C to 100°C. That’s the "sweet spot" for softening thin PLA strands without turning the whole part into a plastic puddle.

Here's a simple step-by-step procedure for grooming:

1. Set the hair dryer to "high heat/low flow".

2. Move the dryer in circular motions around the Yeti mask from about >10cm away.

3. Once the strands feel slightly limp, this should be clearly seen, "train" the hair downward or to the sides. Be creative!

4. Switch the dryer to the "cool shot" setting to instantly lock the style in place!

And that is it!

And finally build your hairy Otto Yeti!

Because I don't have a HP Otto to test it,  I've added a Gemini AI rendering using a photo of the 3d printed part of the final fluffy hairy Otto Yeti!

Tech stuff

The hairy Otto Yeti was modeled in OpenSCAD, and I've 3D printed the final version to test all the fabrication workflow and specially the hot grooming procedure. 

There's a OpenSCAD file for you to play with. This OpenSCAD script needs the 'hp_faceus_ser2.stl' file from the 'HP Robots | Otto Starter' which I've included here for completeness. You can, and should!, generate all variations of hairy Otto by editing the OpenSCAD script!

Final comments

I've chosen a contaminated printed part to generate the AI rendering, I've been using black filament and did not conveniently cleaned the printer bed. Everyone suffers from this, so I decided to keep the glitch for everyone to see it! It also shows on the Gemini AI generated images :D

Also, I would like to thank a young contributor that help me build the Otto Yeti and make the set of the given photos.

It was fun doing this! 

Happy printing!

Personal note on the contest results

It was fun making this entry for the contest, but I think that the competition was not totally fair, the winning models are of little to no use to the target audience that uses Otto: children, teenagers, and people who actually want to learn robotics with 3D printing. In the end it looks like an exploitative marketing gimmick using the competitors' work.