6 replies to this topic

[matt b]

Hey guys, sorry if this is a very obvious question but does anyone know of a good file format for getting data back and forth between maya and houdini? I've heard FBX is a pretty solid file format but I don't know if either of them have native export/importers. I'm probably going to be creating geometry in Maya, running rigid body simulations and effects work in houdini and then exporting back into Maya for rendering.

Anyone got any advice?

[Marc]

As a default that both packages can read, obj is your best bet. It's probably not the nicest format to use... but it's the easiest .

Cheers
M

P.S. moving to maya section...

[matt b]

Thanks, obj does indeed work fine for geometry but Im pretty sure it doesn't save out animation. I've noticed some mention of a .chan file from houdini... what exactly is it?

Also, on a largely unrelated topic how do you save out geometry from outside a SOP? Or how do you say bake a simulation and import it into a SOP so you can save it?

[lisux]

matt b, on Oct 31 2005, 12:33 PM, said:

Thanks, obj does indeed work fine for geometry but Im pretty sure it doesn't save out animation. I've noticed some mention of a .chan file from houdini... what exactly is it?

Also, on a largely unrelated topic how do you save out geometry from outside a SOP? Or how do you say bake a simulation and import it into a SOP so you can save it?

A .chan file is an ascii file with all the values for every frame in every attribute yo export yo the file. Is the animation in raw format.
To export an nimation you can export a sequence of .obj files, see this:
http://odforce.net/tips/h2m.htm
To save you geometry you can uns the Save Geometry option, right click on a SOP node, or use the Geometry ROP.
for animation my advice is to export all to a sequence of .ob file, and he transform the file to a .bgeo sequence using the Geometry ROP.

[nassosy]

For those who haven't browsed the documentation of both packages, I'd like to mention that: Houdini .chan == Maya .mov
Export your animation from houdini in "chan" file format (make a note of how many chanels are written to the file and the sampling rate, because sometimes it is not obvious. Also note the frame range of the exported data).
Rename the file extension to ".mov"
Go into Maya and "import" it, making sure you put the exact same number of channels (that are in the file) in the import dialog box. Otherwise it will fail.
It is important to remember that Maya imports one value for each frame, that means that depending on the sampling rate that Houdini used when exporting, you will have to rescale the animation data in the Graph editor.
Last but not least a note to those that want to import sound waveforms as animation data from Houdini to Maya.
Maya has a hard time with such amount of animation data, so a good idea is to export the anim to FBX and use MotionBuilder (for those who have access to it) to resample it, otherwise be prepared for long hours of waiting, since the resampling code for the Graph Editor in Maya is written in MEL and that makes it VERY SLOW.

[lisux]

nassosy, on Nov 11 2005, 02:58 AM, said:

For those who haven't browsed the documentation of both packages, I'd like to mention that: Houdini .chan == Maya .mov
Export your animation from houdini in "chan" file format (make a note of how many chanels are written to the file and the sampling rate, because sometimes it is not obvious. Also note the frame range of the exported data).
Rename the file extension to ".mov"
Go into Maya and "import" it, making sure you put the exact same number of channels (that are in the file) in the import dialog box. Otherwise it will fail.
It is important to remember that Maya imports one value for each frame, that means that depending on the sampling rate that Houdini used when exporting, you will have to rescale the animation data in the Graph editor.
Last but not least a note to those that want to import sound waveforms as animation data from Houdini to Maya.
Maya has a hard time with such amount of animation data, so a good idea is to export the anim to FBX and use MotionBuilder (for those who have access to it) to resample it, otherwise be prepared for long hours of waiting, since the resampling code for the Graph Editor in Maya is written in MEL and that makes it VERY SLOW.

Thanks nassossy for the info.

[deecue]

Quote

Maya has a hard time with such amount of animation data

i actually rarely ever use the sampled audio waveform.. i think the only time i did that was to make some virtual speakers that would vibrate in and out and i wanted them to react the same way a real speaker worked.. for most (practically all) other cases, you don't need the original audio channel sampled at 44,100.. most of time, audio driven stuff just needs the amplitude of the wave.. so essentially you could cut down your data dramatically by just using the envelope of the waveform.. then resample that at a much lower rate depending on what your frame rate is and how much subframe information you want.. then of course after that you can pass it through and filters, mathematical, channel tuning type chops if you want..