SyFlex in "It's a Boy"


Independent animation movie


Client: Breakout Trust
Director : Julian Tewkesbury
Production Company: Redwing Animation and Tank
Released: Christmas 2005
Project website:
Director's website :


Julian Tewkesbury worked with SyFlex for all the cloth animation in his Christmas film, "It's A Boy". The film involves many human characters and is rendered in 2D cartoon style. It is told from three little birds' eyes as they try to save Mary's baby from the clutches of the evil King Herod.


Director Julian Tewkesbury shared with us a few clips from the film and gave us some extra details on each one of them:

Clip#1, Mary sinks to her knees after the angel leaves her:
This was quite an early SyFlex shot for me, but it works very well. I made a special collider to simulate the floor. It was necessary to make the collision distance quite large so that the cloth didn't fall through the collider. As a result the floor collider had to be placed below the model floor level. The only way to ensure that Mary's skirt flopped to the model floor (and didn't either sink through it or stop short) was to run the simulation and then adjust the floor collider's position to correct any mis-alignment. The simulation then had to be run again. It took several goes before the skirt ended up in the right place.

Clip#2, King Herod and one of his assistants:
A special low-resolution version of Herod's chair was made to act as a collider for his robes. To make the robes rest properly in the chair, it was necessary to animate Herod being lowered into position slowly (as though by a crane!) before the start of each shot, while running the SyFlex simulation.

Clip#3, Mary and Joseph try to get a room at an inn run by an irritating little man called Garrulus:
The flame on Garrulus' lamp is a Syflesh object. This is a low resolution poly sphere tweaked into a drip shape. It was then converted into SyFlesh with gravity set to a negative number (so that it pushed the flame upwards) and a weak drag field added. The bottom vertices of the flame were pinned to the lamp wick. The next two rows of vertices were also pinned, but the tolerance was set progressively greater for each row so that more movement was allowed. The simulation worked in near real-time, so it was very quick to test and adjust the various settings to get the best flame movement as the lamp was waved about. The flame was textured using a lambert material with the glow set to hide the actual object.

Clip#4, Shepherds on a hillside near Bethlehem are amazed at the sight of a new star in the sky:
As with Herod, the shepherds lying on the ground had to be lowered into place gradually before their shots so that their clothes would rest on the ground properly. A special ground collider was made for this. It was a fairly low resolution object, and, in order to prevent the clothes falling through it, the collision distance had to be set on the high side (about 0.1). Therefore, the ground collider had to be placed below the actual ground surface so that the shepherds' clothes appeared to be resting on the ground, and not floating above it.

I was pleasantly surprised at how well the Sycloth behaved for these shots.

Clip#5, The shepherds visit Mary and Joseph in the stable at Bethlehem, one of them holding the captured quails:
The net containing the quails, which is carried by the shepherd was modelled flat. This was then turned into SyCloth and pinned to an animated poly torus which picked up the outer part of the net and pulled it upwards and inwards to appear bunched into the shepherd's hand. A simple collider object was used to estimate the position of the quails. This was animated to move downwards slightly so that the net appeared to be carrying the weight of the birds.

Once a satisfactory net shape had been achieved, the SyCloth was duplicated and exported as a poly mesh. The new mesh was then fixed into the shepherd's hand and animated using a lattice.

Clip#6, The quails attempt to stop the three Wise Men from seeing the baby Jesus. They think the Wise Men will betray Him to King Herod who wants Him killed:
This is a nice piece of action showing how Sycloth moves well and enhances the appearance of the animation.

Garrulus jumps about so much that the cloth, although pinned to his neck at the collar, still flapped over the top of his neck and stuck through his head. This was easily overcome by adding in an extra collider for his head - just a simple poly sphere, parented to the head joint.


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