Oddly easy things

I’ve been playing around with blender again. Blender, for those who’ve never encountered it, is a software package ostensibly for modelling and animating in 3D but which has extensive capabilities for video editing, 2D animation, CGI/VFX, physics simulations, and a lot more besides. It’s also free.

While I was playing around with blender, my brother sent me a picture of a molecule sitting on his desktop. He’d been sitting in a presentation and the presenter had shared a QR code that let anyone download the 3D model of the molecule he was talking about and have it appear there on their desktop. I’m not sure how useful that is – I’m no chemist – but it’s kind of cool.

I’ve seen this kind of thing all over the place and I wondered how difficult it would be. It turns out that, if you have an iphone and a dropbox account, it is very easy¹. Blender will export files in “usdz” format², which an iphone will open in an AR viewer. Download the model, wave your phone around a bit so the camera can work out the geometry of the environment, and *poof* there it is³. Dropbox allows direct access to files from a URL.

There are limitations on the how complex the 3D model can be – fewer than 50,000 polygons, maximum of 3 materials, no polygons with more than 5 corners etc, no procedural textures, no modifiers, max 2k image textures – and filesize needs to be kept relatively low. This turned out to be the tricky bit for me. I don’t tend to think too hard about such things, but there are a couple of quick tricks that can quickly reduce the number of polygons⁴. Fixing the textures is a bit trickier but you can always bake them out to an image file.

All in all, between deciding to try it and seeing the final result took about 2 hours. An hour and a half of that was cajoling an existing model into the constraints mentioned above with a few false starts⁵.

So, anyway, here’s a TAO buoy on my garden path. I could walk round it, or if feeling lazy, twirl it round in front of me. I can think of no earthly use for this⁶, but it is fun. If you’ve got an iphone, you can try it by clicking this link and then “view”.

1. Oddly easy: it’s the kind of thing that feels like it should be difficult but turns out to be easy. Contrast with oddly difficult: stuff that seems easy and turns out to be very very hard. ↩︎
2. Universal Scene Description Zipped format. ↩︎
3. Or isn’t. I find AR slightly bamboozling. People make fun of cats for not understanding that something on the TV isn’t actually behind it, but that’s me with AR. ↩︎
4. e.g. select all vertices in an object and then do a “limited dissolve”. I have no idea what a limited dissolve does, but it did the job. ↩︎
5. On my first attempt, it turned out my model was 40m high, which was slightly confusing as I was inside it. ↩︎
6. Not true, I can think of loads, but few are practical. ↩︎