Arnold
Strands are our friends
And so is Psyop!
This little commercial project from a while back was a LOT of fun. A very small team of us (5 or 6 total, I think) made this (plus a few shots more) in just a few short weeks (two or three I forget) at the LA studio, using a hybrid Maya/Softimage approach which Psyop does really well. All models and animation in maya are brought to Softimage for lighting with Arnold and additional ICE effects – in this case, the characters, and stuffing are entirely strands. No geometry aside from the little plastic eyes and their teeth.
Psyop’s lighting supervisor Jonah Friedman wowed me with the system for knitting via strands he built, and how fast he built it. He also quickly made it on my “favorite people” list in general, it was a blast working with him and the others there. The system, which we called “entwiner” builds layers upon layers of strands… these knit characters are built down to every individual fiber. And Arnold powered right through these millions of strands without a blip. Pretty cool. It was so efficient at it in fact, that it made sense to make the “stuffing” out of tiny fibers too, which gave it a nice volumetric kind of feel when lit.
The liquid is a simple lagoa setup, with wet maps generated in ICE. While the commercial was so simple I was really pleased with how the studio took pains to take their clients ideas and give it the very best. A couple of knit characters could have been faked with geometry and textures, but going that extra mile even when time was so short is what really impressed me, and the combination of maya/softimage, ICE and Arnold is a powerful one, as Psyop shows even on small jobs like this. My kind of studio. Thanks for having me you guys.
Points from strands example for Arnold instancing etc.
This isn’t an earth-shattering ground-breaking post, just a simple example of a workaround which came up on the SItoA mailing list…
In Mental Ray rendering out a copy of a Softimage ICE particle’s shape per strand point is easy, just disable the “stranddeform” attribute (when using “generate strand trails” it’s the “loft shape along strand” checkbox.) Now instead of rendering a continuous, lofted result the strand is depicted as a series of particle shapes or instances. Easy enough, and is described as a basic workflow in the softimage documentation.
But when using Arnold as a renderer, particle shapes are lofted no matter what. So how do you get a result where shapes are repeated along a strand? This is the question which came up on the mailing list, and Stefano Jannuzzo and Mathieu Leclaire posted a simple and direct solution: clone (or add manually) a point for each strandPosition on a new cloud. When using add points instead of cloning, you also need to carry over relevant information such as orientation and velocity.
This is a pretty common kind of technique for this sort of thing and is worth putting on the record where people can search for it, so I’ve implemented their suggestion in a compound and example scene here. Enjoy.