View Full Version : FBX file import

12-23-2010, 04:01 PM
Hi all,

I have now been spending days trying to importing FBX files into LW and it don't look great. I remember I did this years ago and all I had to do was "record rest position" r " and everything falls into place.

But not this time? Its OK if I load the FBX file without the animation.

Have anybody had any luck with the FBX files in Lightwave?

Any suggestion would be appreciated.

12-23-2010, 04:55 PM
Yes, I've had problems being able rest bones/joints properly, among a few other problems. I think it's related to the motion modifiers the new importer adds to all the bones/joints. For now, I've gone back to 9.6.1 for FBX import, which has issues of it's own but at least I can deal with them. I think the new FBX exporter is working better though.


12-23-2010, 11:06 PM
If I remember correctly importing FBX and Collada files in 9.x was never fully finished. The reason being that the Lightwave Rotational System (H P B) is different then what is required.

I think it was something about needing to know what order the rotations were applied to the bones in order to get the correct orientation in lightwave. And unfortunately that data isn't written into the file.

Perhaps after the release of LW 10 they can get back to fixing the bug in the system as according to the Lightwave 10 promo material, FBX and Collada are fully supported now. So maybe they can reverse apply the change to the Rotation system to the uses of 9.6.

Then again, I am probably mistaken and everything I said doesn't apply any more.

12-24-2010, 01:05 AM
That sounds about right.

The problem I seem to be having is with their solution for correcting the axis orientation, which is to change the rotation order through a motion modifier plug-in rather than actually correcting the rotations of the items. Because of this second layer of rotational values, I think I'm running into situations where Lightwave isn't sure which rotational value to use, the original or the ones offset by the plug-in. If this is what's happening, it would be helpful if we had the option to bake the new rotational values on import so we wouldn't have to deal with all these motion plug-ins.

Ideally, I want Lightwave to be able to export my Y up rig as FBX to another program so that it appears with the correct rotational axis in another program (which it does now,) and then import the fbx exported from the other program with a rotational axis that's correct for Lightwave (which it still doesn't; well, not really anyway.) At least, to me that seems like how it should work.

The proper solution, I think, is to give the user options in the import and export panels. For example, a list of different axis orientations that the user could choose from.

And then there's the issue with user defined weight maps. I'm pretty sure the FBX format supports them, so I don't know why Lightwave doesn't export them. Instead we have auto-generated weight maps that may possibly work for some generic of human character models, but they haven't worked very well for any of my characters which really need the custom weight maps.

The lack of options makes me feel like Lightwave's FBX IO is being designed to do all the thinking for 'the poor dumb user', and unfortunately the choices being made are not the ones I actually need or want. It's very frustrating.

For comparison, take a look at the Houdini FBX importer in the image below. Granted, some of these options are specific to Houdini, but there are also options listed here that would be quite relevant to Lightwave. (Note the Y up option at the bottom.)


12-27-2010, 08:48 AM
Actually it works. It was the imported fbx model that had some missing bones in fingers and the toe tip. Just had to make extra child bone and apply the right weight map and it all worked fine.I tried a
few other different downloaded fbx models and it all seams to be weight maps problems. Ether missing weight maps on the bones, missing end child_bone or wrong assignment of weight maps. I tested
3 different models from Mixamo and all of the models was somehow screwed up but it was all weight map related.

About Mixamo fbx files the way I see it

First you have to select download Fbx Include Skin. Then you have to go back and download Skeleton Only (to get the motion file that for some reason is not include in the fbx Skin file)

Load your fbx scene as normal and then Load From Scene (Merge only motion envelopes) and there you have it.

At Mixamo you can download different actors for your motion files. But unfortunately you cannot assignee the same fbx motions file to different actors even that the bones looks identical. And it wont even let you
copy/past the motion. And that is very strange if you ask me.

Be aware that Motien Mixer don't recognize the ZYX rotation order Modifier on imported fbx files. Hope that will be fixed very soon...