A method for using Motion Analysis CORTEX for cleaning VICON Nexus Mocap data

This is a very quick note and will be developed a bit further in the future! 

  1. In Cortex in Post Process mode
  2. Open a VICON Rom file in Cortex (File/Import C3d file…)
  3. – you should see some dots representing the markers.
  4. Click the ’New Marker Set’ Button.
  5. Select each marker in turn in the Marker tab on RHand side, in the properties below give each a name and color, im using the VICON conventions, eg LFHD, RFHD etc. When you are done click on the Links Tab and click the Create Links for Template button.
  6. Now click and drag from marker to marker appropriately eg LFHD to RFHD, RBHD to RFHD etc – you also have the option to choose the link colour, this means you can replicate the look of the VICON Nexus stick dude.
  7. On top of the 3d view there is a little tab with Your_Marker_set_name, Rclik it and save it.
  8. Now click the ‘Create Template’ button, if you scrub your anim to an appropriate T-pose you can also select the Tick box to ‘Include the current Frame as the Model Pose’ – which will make a static view of your Tpose that you can see in the 3d options. And also tick the ‘Show Template Linkages’ to show the links between markers – now hit Create Template. (and I think you need to save the marker set again)
  9. This can be used to recognise markers in other takes and to ‘Template Rectify’ segments.
  10. Now you can open another capture, use the  File/Add Marker set to load your maker set then hit the Marker ID button and click each marker in your take to name them appropriately – the links will show up automatically. When you are done, hit Template Rectify to name all markers in all the frame. Now you are good to go for cleaning.
  11. will write more later on Rectify Unnamed etc.

to get into motionbuilder and merge with existing takes:

  • Use CORTEX to clean the VICON data then ending up with a TRC file – the naming for the markers must follow the convention of the target file. ie if you want to merge it later into some other vicon takes then you must get the marker names the same as the Vicon set.
  • CORTEX saves TRC.
  • import the TRC into motionbuilder and apply any rotations to get the figure upright
  • If you want to import multiple takes then select the optical root..
  • ..then File/Motion file import. In the dialogue box just tick Merge and In Selected Heirachy and Create Optical Segments…
  • …If there is an error about trying to merge 39 markers with 40 go back to CORTEX and Delete Unamed
  • Select all the markers and go Motion File /Export save it out as a .c3d..its possible to export multiple takes in one go.
  • open the target file, select the optical root and then Motion File /Import to get the data in
  • Example: i have all of Estzers takes which I cleaned in VICON NEXUS…
  • Then I imported the ROM c3d, made an actor, merged the other Estzer takes and saved the .fbx file
  • Take 14 had problem so I cleaned it in CORTEX and deleted from the .fbx
  • I opened the cleaned .trc in motionbuilder using File/Import Motion File
  • I rotated the marker set to be upright (I cant figure out how to set Y=up in CORTEX)
  • Use File Motion File Export to save out a .c3d
  • Then I open the Estzer .fbx takes file and with the optical root selected, File / MotionFile import to merge in the fixed take.
To export .htr (for Mocapp for example)
  1. have a character driven by the animation, then Plot takes to its skeleton
  2. select all skeleton nodes in schemetic window
  3. file export. Give the .htr a name eg ‘N’ then in the dialogue choose add prefix it will export all takes in the file