Xsi Camera to Houdini

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Hi all!,

I work as fx artist for an animation studio here in spain, and in the next months most of the pipeline will be changed from Max to XSi 7.5. Here is my actual headache, the fx departament is free to decide between XSI, Maya or Houdini, no time, it must be decided in a few days.
We've been learning Houdini for a time and i think it's the best option for fx, but one of the most important things in this case is the connectivity with XSI.

We've been trying several ways to get xsi stuff into houdini and founded Fbx as the one of the best format to import. The problem comes with the camera parameters animation, when we import an xsi scene (fbx or collada) with an animated FOV, houdini reads the transforms animation perfectly but not the camera parameters animation, it keeps the end frame values.

I read in the forum about geting houdini cameras to xsi using .clip files and with the help of a minor plugin, could this be done inversely?.
I suppose i can ask for a sript to cache xsi FOV values and convert them to Houdini Focal Length, but i'd like (i need) to hear your opinions.

And the last thing is for stereoscopy, the tools departament told me they need to know the relation between xsi camera parameter “Optical center shift” and the one we suppose to be equivalent in Houdini “Screen Window X/Y”

Well i hope somebody underestand all this :? . Sorry if my eng is a bit incomprehensible.

Lots of Thanks….any comment will be helpfull.
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I also think that FBX would seem to be the best bet for conversion in your case. The problem is, camera conversion is one of the weakest areas of FBX, which is overall pretty good otherwise. This is in part because different packages often use different camera models, and conversion between all of them is often non-trivial.

Can you attach a sample of a really simple camera FOV animation that isn't being converted correctly? I'd like to take a look at what is going on, since perhaps there may be a simple change I can make which could fix it. Also, for the .fbx file, could you export it in ASCII mode?
Oleg Samus
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Side Effects Software Inc.
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Thanks for your response Oleg, i attach three realy simple files that we are using to investigate: the xsi original file, fbx version and dot xsi 6.0 text version (don't know if this is the ASCII you asked for…. :? )
It's a simple plane with spheres, cones and a torus on it; an extrange camera rotation animation (where collada fails!), and FOV animation from frame 30 to the end. All the camera parameters are converted correctly, but not animated.

Finally today it's been a great day searching for solutions, i'll try to post as soon as posible what we have learned about the relations between Maya, Xsi, and Houdini camera parameters to script a conectivity tool maybe. Also the relation inbetween these packages with the camera offset x/y parameter used in stereoscopy. This probably will be known by many, but hope will help others…..
Thanks again for your interest Oleg, hope this “cameras between packages stuff” can be clearly solved.
Sorry for my extended posts :roll:

Attachments:
ascII.rar (50.3 KB)
con FOV fbx.rar (84.8 KB)
con FOV.rar (69.2 KB)

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Besides of fbx which seams to be the easiest way (at least as long as nothing goes wrong), there are other options perhaps worth to consider. We use simple XSI script to export camera to Nuke's *.chan files. From that it's just one step to import it into Houdini via chops.

XSi script on highend3d:
http://www.highend3d.com/xsi/downloads/tools/3d_converters/XSI-to-Nuke-Chan-exporter-4032.html [highend3d.com]

I think above version needs update to cover all camera details, but it shows how easy it is. Such file doesn't need anything else but a few chops and your camera is in houdini. It turns to be more reliable then fbx which works or not…
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Thanks SYmek!, it's really helpfull an example like this

i'll try to find out how to extrapolate this to houdini. There should be no problem working with parameters like FOV(xsi)>>Focus Length(houd) or Optical Center Shift(xsi)>>Screen Window X/Y(houd) if you know the relation, i hope…
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Ok, i think this is not a problem anymore, exporting scene in fbx and cameras throught .clip files as SYmek said, should be OK. Here is how we're thinking to solve these parameters conversion to save time to anyone with this problem. Hope it helps.
If anyone sees an error please post it, we're still working on this, also we'll post any tool to automate the conversion once we have it.

Thanks for the help!

Attachments:
425px-Angle_of_view.jpg (107.4 KB)

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