In the last post I put one of Dave’s sculptures on the page as something you can turn around in your hands. A few people have already asked how that was done, so here is the whole thing, start to finish, with nothing left out and nothing dressed up.
It started with a problem.
Software that builds a three dimensional model from photographs needs to see an object from several sides. That is the entire trick. Show it enough angles and it can work out the shape between them. I went into Dave’s archive expecting that to be easy, and found that of the thirty two sculptures I had chosen, twenty six exist in only one photograph. One angle. One point of view, taken years ago, often the only frame anyone ever shot.
You cannot reconstruct a sculpture from a single photograph. There is nothing to reconstruct from.
The step that solved it
So instead of hunting for photographs that do not exist, I asked for them to be drawn.
This is the original. A piece Dave made in 2013, painted blue, built out of bolts and screws and threaded rod and a nest of wire.
I gave that single photograph to an image model and asked it to imagine the same object from other sides, and to lay those views out on one sheet.
Now there was something to work from. I fed that sheet to a photogrammetry service, which read the angles, worked out the volume between them, and handed back an actual three dimensional object with its surfaces and colours intact.
Then the part nobody sees
What came back was beautiful and completely unusable. One hundred and twenty four megabytes. One million, eight hundred and fifty eight thousand triangles. Gorgeous on a workstation, and an insult to anyone trying to open it on a phone.
So it had to come down, and this is where Dave’s work fights back in a way I did not expect.
The usual way to shrink a model is to simplify it, to throw away detail the eye will not miss. On most objects that is fine. On this one it is vandalism. The stray filaments of wire and the threads on the bolts are not detail. They are the artwork. Simplify hard enough to hit a small file and you have deleted the piece and kept the lump.
It landed at about five hundred thousand triangles and eight and a half megabytes, with the surface colour, the metal, the roughness and the fine relief all still intact. That is the floor for this sculpture. Below it, the thing that makes it Dave’s stops being visible.
One last detail, for anyone who ever tries this. There are two competing ways to compress a model for the web, and only one of them works in the browser viewer I am using. The other one loads nothing at all and reports no error while it does it, which cost me two weeks of assuming the file was fine. Draco works. Meshopt does not. If you are reading this because you are stuck on the same thing, that sentence is the whole answer.
What this is, and what it is not
The extra angles were invented. They are a good and careful guess at what the back of the sculpture looks like, made by a machine that had seen the front. Everything the camera actually saw is faithful. Everything it did not is interpretation.
So this is not a scan, and I will not call it one. A scan is a measurement. This is a likeness.
I think that distinction matters, and I think it matters more, not less, as these tools get better. Dave built the object with his hands out of hardware other people threw away. The machine and I made a way for you to look at it from the other side. Those are two different kinds of work and only one of them is art.
Thirty one more sculptures are staged and waiting. Now that the process holds together, they can start moving through it.
More to come.
