c3d export into MB

[leith]

I've been working with the new beta of TT.

When I export raw marker data as a c3d and import into motionbuilder, I get errors on longer takes (longer than 10 seconds or so).

I have no trackables in my project. Its just raw markers.

I suspect the issue is that longer takes have more "labels" in them, and exceed the c3d labeling limit.

I'll be updating my motionbuilder soon in hopes that perhaps it would help. but I'm curious if anyone has been successfully importing lots of raw optical data into MB from TT.

If this is a known limitation I'll likely go the route of parsing the csv files and writing them as some other format (TRC or FBX ASCII).

[leith]

erm... yea. there's definitely something wrong with the c3d exporter over here but it has nothing to do with labels. Looks to me like on longer takes, its just truncating the file.

I've worked around it though. I wrote a csv to c3d converter based on your csv format. Works really well. Even got it to automatically split and gap opticals properly.

I'll see if I can give you guys my data tomorrow so you can track down whatever is buggin out the c3d exporter.

[morgan]

We're looking at this now. Testing here shows export of C3D data without RBs works fine into CMotion's Visual3D C3D viewer and MotionLabs' MLS Viewer, but not into Mobu, only when the marker count varies throught the take. Otherwise mobu import looks fine.

Hopefully we can isolate the mobu issue. If you have a test C3D along with a .tim file that would definitely help.

[morgan]

Hey Brad

Just following up on your issue. Our current C3D export is not designed to handle variable marker counts from frame to frame. The CSV export option is definitely a better choice here as marker counts / data can vary from frame to frame.

That said, we're looking @ an update to our C3D exporter to support this.

Can you let support know if you need this before the 2.2 final, or if you can work with the current CSV export?

thx

Morgan

[leith]

Yea I'd like to send you guys a whole bunch of data actually.

do you have an ftp where I can do a pretty substantial upload?

Should I contact you guys via phone or email to set something up?

[morgan]

Yes definitely.

Contact Vince @ support@naturalpoint.com and he can get you set up.

[litch09]

I have another question regarding the C3D export.

We have four trackables which track well. We then export these and load in Visual 3D. From one trial to the next, the marker names (which are numbers) change so that the same marker is called something different each time. The trackable group numbers also change.

Questions -

Is the C3D export supposed to identify individual markers of trackable objects and export these in a specific order, or are the marker names randomly assigned? Are we doing something wrong?

Should trackable objects be given the same marker cluster groups in the C3D file (e.g. Trackable 1 = 1, 2, 3, 4; Trackable 2 = 11, 12, 13; Trackable 3 = 21, 22, 23, 24)?

Is it possible to have the trackable name listed in the C3D marker names (e.g. Trackable1_1, Trackable1_2 etc)?

I'm happy to send through some data if need be.

Cheers, Glen

[morgan]

Hey Glen,

The C3D data contains labeled marker positions. These labels correspond to the labels in TrackingTools. There is no particular order to these markers.

Tracakble objects are not stored in the C3D file. Just point data (both labeled and unlabeled).

Prepending with the Trackable name is a great feature. If this will resolve your issue can you let us know? We'll try to get this in before the final release.

thx

Morgan

[beckdo]

Hey Glen,

Just a short follow-up regarding trackable markers. They are labeled 1,2,3,4.. for the first trackable, 11,12,13,14.. for the second trackable.

The order of the individual markers of a trackable 1,2,3,4 are defined when you define the trackable. When you click-drag and select 4 markers, for example, to define your trackable you get a random order. If you need a specific order, hold the control key down and click the markers in the order you want them to be defined to create your marker selection before creating the trackable.

[litch09]

Hi Doug,

We seem to be having some trouble getting this to work. In fact often things go totally crazy. It seems that if load a timeline file and then export from the first frame, that things seem to go OK. However sometimes when we export (typically when we have played through the timeline a little) the markers are labelled in a quite random order in the exported C3D file and sometimes there are periods when the markers jump around crazily.

Can I send some example files to support@naturalpoint.com?

Also, is there any way of getting the trackable name into the C3D file so we know what trackable is what? Eg. trackable1_1, trackable1_2 etc?