Inverse Kinematics Window#

Inverse Kinematics Window

The Inverse Kinematics Window is designed to extract time‐series Euler angles from your wing’s 3D point data. Follow these steps to import, visualize, and export your kinematics:

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FlapKine expects pre-computed 3D coordinates (e.g., from DLTdv [1]) rather than raw multi-view images/video. Use this workflow to import your landmark trajectories:

  1. Prepare your CSV file The file must contain one header row and one data row per time step, with these columns:

    pt1_x, pt1_y, pt1_z, pt2_x, pt2_y, pt2_z, pt3_x, pt3_y, pt3_z, pt4_x, pt4_y, pt4_z
1.23, 4.56, 7.89, 2.34, 5.67, 8.90, 3.45, 6.78, 9.01, 4.56, 7.89, 0.12
1.25, 4.58, 7.91, 2.36, 5.69, 8.92, 3.47, 6.80, 9.03, 4.58, 7.91, 0.14
...

    • pt1_x, pt1_y, pt1_z: X, Y, Z coordinates of point A

    • pt2_x, pt2_y, pt2_z: X, Y, Z coordinates of point B

    • pt3_x, pt3_y, pt3_z: X, Y, Z coordinates of point C

    • pt4_x, pt4_y, pt4_z: X, Y, Z coordinates of point D

    Points (pt1-4) correspond to the four markers (A–D) shown in the below image and processed in DLTdv.

Wing Point Configuration

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These points were specifically selected as these are aligned along the two body axes (\(\hat{b_{1}}\) and \(\hat{b_{2}}\)), the other axis (\(\hat{b_{3}}`\)) is obtained by taking cross-product of these two. Then these are analytically solved to give euler angles. See Inverse Kinematics API

  1. Choose Euler Sequence

  • In the Euler Order dropdown, pick your desired rotation sequence (e.g., ZYX, XYZ, etc.).

  • This order determines how Angle I, Angle II, and Angle III are computed.

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  1. Visualize Point Trajectories

  • On the Left Panel, select point A, B, C, or D to see its 3D trajectory plot over time.

  • Use this to verify tracking accuracy before computing angles.

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  1. Compute & Preview Euler Angles

  • Once the sequence is selected, the window auto‐calculates Angle I, Angle II, and Angle III at each timestamp.

  • Real‐time line plots appear below the 3D view for each angle component.

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  1. Export to Sprite Creator

  • When you’re satisfied with the results, click Finish.

  • The computed Euler angles and selected sequence are sent directly to the Sprite Creator Window for further processing.

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References