Pete Mc Nally's Blog

One evening last week I set about taking Project Photofly for a spin. As I mentioned in an earlier post, photofly is a cloud based service that generates a textured 3D mesh based on photographs that you upload to their server. It really piqued my curiosity and I’ve been dying to find some time to give it a go, so one evening after work I was in the garden and saw my son’s play tunnel crumpled up on the grass. 20 photographs later and I had something to test with, so I uploaded them to Autodesk’s cloud service using the Photo Scene Editor downloadable from their site.

It took about 30 minutes in total to upload the photos , preview a draft mesh and commit the final model, progress bars advise you of the current status, or you can choose to be mailed when the job is complete. The visual fidelity of the end result was good, although there were several holes in the mesh from not having enough photo coverage. The Photo Scene Editor allows a few export options, I chose obj and imported it into 3DSMax. The scene contained three triangulated meshes and three 4096×4096 textures which were pretty high-resolution considering I used a 5mp point-and-shoot Sony Cybershot camera. Visual fidelity is high, although the mesh topology and UV layout is pretty hideous as you’d expect. It also doesn’t cope too well with long extrusions, for example flowers or poles but I’d expect that to improve with more photographs taken (they recommend about 50 pictures for a human head).

I set about retopologising the tunnel model (using Matt Clark’s excellent WrapIt) with a much lower proxy mesh, trying to keep edge loops where they could best support the circular frames beneath the canvas, then used Render To texture to export a new diffuse and normal map. You could also extract displacement in Mudbox if you need to reconstruct the initial detail, leaving you only to remove the highlights and shadows in the diffuse texture to make the model more versatile for use in other lighting conditions. Here is a clip of the results:

I like Photofly, I hope it’s a service that I hope Autodesk continue to provide for free. I like that it is portable, you can snap a sequence of photos on your camera phone, upload them on a low spec netbook and download the scene for later use on your workstation PC, without having to worry about horsepower along the way – all of the automagic is done in the cloud. Most folk never leave the house without their smartphone so it’s nice that you don’t have to carry additional heavy tech with you if you chance upon something you want to capture. With some retopology and texture work you can have a model reusable in other scenes or games with normal/displacement maps as close to real life as you’ll get without a 3D scanner. In fact, you could probably use Photofly’s stitching technique to generate a skydome for re-lighting and environment maps too.

I took my camera around the grounds of Luttrellstown Castle on Sunday and took some pictures, I’ll stick the results up here when I get to processing them, they are slightly more complex than this first go!

~ by petemcnally on June 20, 2011.

Posted in Personal Work
Tags: 3d, 3dsmax, capture, game art, Marmoset, photo, Photofly, photogrammetry, realtime