HPotter Order of the Phoenix end battle

[quinniusmaximus]

anyone have any leads, behind the scenes, information on how they did the particle effects at the end of the last Potter film. Specifically the kind of smoke/particle trail stuff that was coming off of the characters when they were flying around battling?

Was it done with Houdini. From the bits of other work I've seen. It seems like it would fit.

Thanks.

[michael]

http://features.cgsociety.org/story_custom.php?story_id=4225

http://vfxworld.com/?atype=articles&id=3362&page=1

[quinniusmaximus]

Ok...

narrowing down what I'm looking for... Any first hand (or even second hand) experience or some kind of tutorial on soft bodies in houdini.

on how these specific effects were achieved with Houdini:

The trailing ribbons of cloth and tendril-like vapor plumes were animated in Houdini, whilst the billowing clouds of smoke were created in Maya fluids. All elements were then rendered in with a combination of PrMan and DNB, Double Negative's proprietary volumetric renderer

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[old school]

As for the trailing ribbons of cloth, have a look at the wispy smoke tool in the FX Tools (download from your Houdini shelf). It creates a trail of particles and then skins them in to a surface. You can then render the surface with a x-ray type shader to create wispy looking stuff.

The implementation in the Wispy Smoke tool is quite generalized in that it can take any geometry. It also has options to kill particle rows to put a finite end to your trailing geometry.

You can build up your own using either particles or the Trail SOP.

Again so many ways to do this.

[michael]

search around here for examples of particle effects (and look through all the particle examples in the documentation)...I'd be very surprised if 'soft bodies' were used at all in the Houdini work on HP...

and have a look at the Trail SOP...

[quinniusmaximus]

there were some soft body work...

Each child casts a unique version of the Patronus with its own individual animal at its core. Created in Maya, the 3D creatures were exported to Houdini, which was used to generate spiraling soft body trails.

Thanks for everyone's responses.. Exactly the kind of information I was looking for.

Also, any suggestions on the best way to get something like "trailing ribbons" out of houdini and say into Maya?

[old school]

fbx export from Houdini includes Vertex Caches which allow effects with changing topology in Houdini work in Maya. That would be the easiest way IMHO.

[Alanw]

Hosuk Chang has a scene you can download with a soft-body ribbon / particle effect.

http://www.hosok2.com/project/bird/bird.htm