Hi,


A question (again) regarding iPi Mocap Studio (iPiMS) and FBX export: if the original project is recorded at 60 fps, how does iPiMS define the frame rate when the project (or ROI, the region of interest) is exported as FBX?

An example: I have a project of 1426 frames. My ROI is from frame 190 to frame 1148 = 958 frames. If I export the ROI using FBX and then open the resulting FBX file in Autodesk's FBX viewer, it shows only 479 frames, which is exactly half of my ROI (and I don't mean 479 frames from the start, but every other frame). Are the exported FBX files always 30 fps?

I have actually tried to find out, if the FBX format saves the fps value at all... Are FBX files pure animation with no concept of time at all?


Your FBX newbie, HeiLei

No. Actual FPS depends on FPS of your motion capture file.

It is possible that FBX SDK reduces some keyframes during export. (I checked our source code and it seems that it should not, but theoretically there can be some bug with our FBX options).

However, the overall look of exported animation should be very close to original motion capture (e.g. it should not be faster or slower then original motion capture).

Thanks Michael! Would it be possible for you to test this with Autodesk's tools? Their viewer is available at http://usa.autodesk.com/adsk/servlet/pc ... d=10775920 (the viewer is embedded in the FBX 2013.3 Converter package).

If you export a short 60 fps project as FBX, and then open it with FBX Viewer, do you see all the frames, or has the data been resampled at 30 fps (as it is in my case)? The number of frames that FBX Viewer reports is exactly half of the original. The quality of the animation itself is just fine; there is no visible difference to the original. I'm just curious to know what's happening here.

The same thing seems to happen with the tutorial project as well: it is recorded as 50 fps, and the ROI is 822 frames long. If I export it as FBX and open the resulting file in Autodesk's FBX viewer, it now has 492 frames. 30/50 x 822 is 493,2, very close to 492. The FBX SDK seems to resample the frames to 30 fps?

Hi
Indeed, the frame rate of an exported FBX was not set correctly to the FPS of an animation. Though the timing of the animation was set correctly, so it was automatically resampled - either when saving or when playing back, not sure.
In Mocap Studio 2.6.1.163 this behavior is fixed, and the frame rate of FBX is set correctly.

Ok, thanks for the fix!