We bought a giraffe head coat hook a while back – not sure why. Its made of cast aluminium. I have since seen the same head in a couple of other places – restaurants, shops. The most recent was in a place we stayed over Christmas. It is as if someone bought a container ship of the things (from China?).
As Christmas listlessness took over in the place we were staying I wondered how I could make a similar hook, but with a bust of the dog’s head (the dog being the most accessible wildlife at hand). I’d have to:
- Create a digital 3D model of the dog’s head.
- Making a casting mould
- Casting it from aluminium
I want to be able to cast more than one too: I want to be able to make my own container-full load of weird dog head coat hooks, if I feel so inclined.
Modelling the Head
I toyed with modelling using T-splines for Rhino from scratch. I watched a couple of T-Splaine Youtube vids and decided this was going to be pretty hard to do well. I moved on to photogrammetry to get the basic head geometry using Autodesk’s ReCap software – I played with this previously here. Turns out in the past few months Autodesk has revisited their pricing and what started off as a toy back-in-the-day as 123D Catch has moved through the freemium ReMake into full subscription pricing with ReCap and ReCap Photo. That’s okay, I get it – it must take some resources to put that kind of tech together and cloud-run the algorithms and whatnot. It’s just a bit of a pity, rather closes the door for hobbyists/ consumers. Autodesk does give you a 30-day trial for ReCap Photo, so that’s what I used.
The dog, being the dog, refused to stay still long enough to take photos of her head at 50+ different angles. I decided to wait until she was asleep and get half her head and fudge the rest by mirroring and cutting and pasting.
I sent 60 odd photos off to ReCap and got the 3D model back in the morning – pretty pleased with the result.
In Recap, I deleted all the bedspread and weird bits where the dog morphed into the bedspread – ReCap has some great tools that follow the mesh so you ‘paint out’ the bits you do not want quite accurately.
I had intended to next stage to be done in Rhino5 3D. I have had never really needed to play with meshes in Rhino and I found its offering pretty woeful in terms of creating new meshes. Autodesk MeshMixer (which is still free, for now) is pretty good though, and using it to sculpt was actually pretty fun:
- Rotated the dog’s leg haunch and neck from a lying position to a standing position
- Mirrored the mesh to make the dog’s full head and neck
- Used Meshmaker’s sculpting tools to create the ears (which weren’t picked up so well in the photo model)
- Smooth out and tidy up the model
- Form the nostrils and mouth
- Introduce a little asymmetry to make it a bit more organic and hide that I had just mirrored the base geometry.
I used Rhino to do the eyes. As the dog was asleep when I took the photos the 3D mesh had no features around the eyes. I set a photo of the dog as the background in Rhino and oriented the model so it matched up. Then I traced the eye shape off the photo, extruded these into the head mesh and cut out the shape.
The eyeballs I just did as two spheres behind the eyeholes which I trimmed to the extruded outlines. I then meshed these trimmed surfaces and lofted the mesh edges (for compatibility with the meshed head) to the eyelid edges in the head. I meshed the lofts, rebuilt surface norms.
Back to MeshMaker
Back into Meshmaker (Rhino and I struggled to make the outcome joined meshes a watertight solid), Meshmaker did not have any problems. Also added the backplate in MeshMaker for wall mounting.