Differences

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--- visual3d:documentation:third-party:theia [2026/06/03 20:28] – Added details about "Kinetic But No Force Assignment" and Shadow Segments. wikisysop
+++ visual3d:documentation:third-party:theia [2026/07/23 13:49] (current) – Corrected version number for Theia3D Apex. richard
@@ Line 6: / Line 6: @@
 Each ROTATION signal consists of 17 float values per frame: sixteen values represent the 4×4 transformation matrix, and the seventeenth is a reliability metric. These signals are stored sequentially in the C3D file. This data type is used in practice because if a segment’s origin is defined at the proximal end, the ROTATION matrix provides a description of both the position and orientation of that segment. This eliminates the need for additional calculations to estimate pose and makes data management easier, since the pose is a single signal.
-This integration supports all Theia3D software versions including [[https://docs.theiamarkerless.com/|Theia Axiom v2025]], [[https://docs.theiamarkerless.com/version-2024.1.0|Theia Apollo v2024]], [[https://www.theiamarkerless.com/blog/theia-2023-patch-3| Theia 2023]], Theia 2022, and Theia 2021.
+This integration supports all Theia3D software versions including [[https://www.theiamarkerless.com/blog/theia3d-apex---the-next-generation-of-markerless-motion-capture-has-arrived|Theia Apex v2026]], [[https://docs.theiamarkerless.com/|Theia Axiom v2025]], [[https://docs.theiamarkerless.com/version-2024.1.0|Theia Apollo v2024]], [[https://www.theiamarkerless.com/blog/theia-2023-patch-3| Theia 2023]], Theia 2022, and Theia 2021.
 ===== Automatic Model-building =====
@@ Line 20: / Line 20: @@
 ==== Kinetic But No Force Assignment ====
-The Right and Left Foot segments are defined as kinetic segments but are not allowed to have forces assigned to them. This ensures that forces are assigned always assigned to the Right/Left Toes segments which are the most distal segments in the kinetic chain.
+For the automatic model built for Theia3D output data, and other similar markerless systems, force assignments at the feet are intentionally assigned to the toe segment rather than the foot segment. This is accomplished by defining the foot segment as "Kinetic with no force assignment" while the toe segment is defined as "Kinetic". This ensures that forces are assigned always assigned to the Right/Left Toes segments which are the most distal segments in the kinetic chain.
+The reason for this is that the Net Joint Moment and Joint Reaction Force at the ankle are identical regardless of which segment is assigned the force, as they are part of the kinetic chain, but if the force is assigned to the foot segment then the metatarsal moment cannot be computed.
 ==== Shadow Segments ====
@@ Line 35: / Line 37: @@
 ^ Theia3D Version ^ Notes/Description ^ Visual3D Version ^
+| Apex (v2026.1.4) | Full release of Bat and Ball tracking | v2026.07.1 |
+| | Automatic model-builder supports sex-specific regression equations from de Leva (adjusted Zatsiorsky-Seluyanov) for segment inertial properties | |
 | v2025.2.2 | Added Ball Modelling to automatic model | v2026.04.1 |
-| v2025.2.2 | Implemented Bat and Ball modelling using multiple subjects, allowing multiple balls and bats to be modelling within a single session | v2026.04.1 |
+|  | Implemented Bat and Ball modelling using multiple subjects, allowing multiple balls and bats to be modelling within a single session |  |
 | v2025.2.0 | Introduced Bat Tracking feature | v2026.01.1 |
-| Axiom (v2025.1.0) | Separate inertial parameters for male and female participants. | v2025.03.2 |
+| Axiom (v2025.1.0) | Separate inertial parameters for male and female participants | v2025.03.2 |
-| Apollo (v2024.1.0) | Introduction of new model. | v2024.08.4 |
+| Apollo (v2024.1.0) | Introduction of new model | v2024.08.4 |
 |  | Model 10 | v2024.02.1 |
 |  | Initial Model | v2020.03.16 |