Wing Beat Animation

Project credit

This is one of student projects of HNRS3035 2016 class.

  • Student : Christina Daigle
  • Faculty: Prof. Dominique Homberger
  • Viz instructor: Dr. Jinghua Ge

CT data and segmentation of wing bones

The CT data of a House Sparrow Passer domesticus is provided by Dr. Homberger to students. Christina segmented the wing bones using software Avizo (LSU campus license available in Frey 101 vizlab). The below screenshot at left is a visualization made by Christina, with surface view of segmented individual bones shown against CT data volume rendering. Each individual bones are exported to Wavefront OBJ data format from Avizo, then imported into Maya. In Maya we can smooth and color-code the bones, see image down right.

_images/aw-model-ct-2.png _images/aw-model-1.png


FK vs. IK

The wing rig is a combination of IK and FK. Four controls are built to manipulate the rig:

  • Carocoid control: A single chain IK is applied to Carocoid joint, control translation move the IK end point to rotate the Carocoid

  • Scapular control: A single chain IK is applied to Scapular joint, control translation move the IK end point to rotate the Scapular

  • Elbow polvec control: A rotate plate IK is applied to the first two segments of wing, control translation changes the IK polvec to rotate the elbow

  • Wrist and tip control: control translation moves the rotate plate IK end point; control rotation rotates the tip joint directly (FK). The FK here allows full control of tip rotation.

    _images/aw-rig-default.png _images/aw-rig-match1.png

Image planes and pose matching

Four Phases of the wingbeat cycle. Figure from [Jenkins11]

_images/aw-Dorsal-w.png _images/aw-Lateral-w.png

The screenshot below is made by Christina. It shows the image plane setup in Maya. The wing is pose matched to the first pair of cycle figures.


The following images shows the top and side view of a pose match. The cycle figures are inverted to enhance constrast.

_images/aw-match1-top.png _images/aw-match1-side.png

Keyframe animation and playblast

The four cyles are pose matched and each set as a keyframe, then the first pose is copied as the last keyframe to form a complete wing beat loop. The playback of keyframe animation simulates the bird fly motion.

If video can’t play, right click the video image and choose “Download Video” or “Save Video as”.


[Jenkins11]Jenkins, Farish, Kenneth Dial, and G Goslow. “A Cineradiographic Analysis of Bird Flight: The Wishbone in Starlings Is a Spring.” Science 241.4872 (1988): 1495-498. JSTOR [JSTOR]. Web. 10 Mar. 2011.