Inspect3D Tutorial: Analysis of Baseball Hitters at Different Levels of Competition: Difference between revisions

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If you would like to skip the build CMZs Files and MetaData tutorials, you can:
If you would like to skip the build CMZs Files and MetaData tutorials, you can:
*Download this pre-built CMZ workspace.
*Download this pre-built CMZ workspace.
==Refining Hitting Data==
From here on it is assumed that you either have: a) built CMZs from scratch using the hitting data set, or b) downloaded the pre-made CMZs linked above.
The zip file openbiomechanics-main has a metadata file for the hitting data set which you can view at your convenience. This metadata file has a number of categories including player age, bat weight, hitting side etc.
Let's say we want to query this data set, but we '''only''' want data from subjects that are under age 20.
We start by loading library with the hitting data set, navigating to the Query Builder dialog, and opening the Auto-Populate dialog. Ensure that "Baseball" is checked. Find the "Refine using signal" checkbox and click "Add". Then you can enter your query refinements.
[[File:autobuilder hit.png|450 px|center]]
When refining queries it can be helpful to have the metadata file open, so that you can see the values it contains. Note that in this case, accessing athlete_age has been set as a global metric, and you will not be able to find the meta folder unless Global Value is checked.
The result of this procedure is that data is queried only if it meets this refinement category, and the refinement name will be applied as a suffix to the end of the signal name.

Revision as of 16:57, 18 September 2023

Abstract

The OpenBioMechanics project is an initiative started by Driveline Baseball Research & Development, and provides the general public a marker-based motion capture data set of 100 pitchers and 98 hitters at different levels of competition [1].

The authors provide raw data without any reports or analysis, allowing the general public to use it as they see fit. While numerous scholarly articles provide in depth looks into the biomechanics of the baseball swing [2], there is a noticeable scarcity in articles that delve into biomechanical disparities between various levels of competition, such as contrasting differences between college and high school baseball players.

This tutorial is designed to demonstrate the use of Inspect3D to analyze the variance in pelvic angular velocity in internal/external rotation between high Blast bat speed [3] among college and high school baseball players.

Downloads and Relevant Links

To follow along with this tutorial, ensure that your version of Inspect3D is at least v2023.08.08. Earlier versions will not have the Build CMZ feature. After verifying that you have the correct version of Inspect3D, download the following two zip files.

  1. OpenBiomechanics Project: Driveline Baseball data
  2. C-Motion Specific Files

Please note, these downloads contain a large amount of data. Building CMZs is a slow process, so if you want to speed it up to follow along with building CMZ portion of this tutorial cut the number of datasets under openbiomechanics-main down to 3-5 subjects.

If you want to skip the Build CMZ step of this tutorial and focus on the metadata applications, you can:

  • download this pre-built CMZ workspace.

For more technical information about loading metadata, see: Metadata Documentation

Build CMZs for Hitting Data

In the Build CMZ dialog:

  1. Set the path to: C:\...\openbiomechanics-main\baseball_hitting\data\c3d
  2. Set the Metadata File to : C:\...\openbiomechanics-main\baseball_hitting\data\metadata.csv
  3. Set the MDH File to: C:\...\openbiomechanics-main\baseball_hitting\code\v3d\model\hitting_v1_model_hybrid.mdh
  4. Add the following scripts and ensure they are in the correct order:
    1. C:\...\CMotion Files\Filter.v3s
    2. C:\...\CMotion Files\Events.v3s
    3. C:\...\openbiomechanics-main\baseball_hitting\code\v3d\CMO.v3s
  5. Click Create CMZs
  6. A metadata dialog box will appear after clicking Create CMZs. Make the following changes in this box:
    1. Height Units: in
    2. Weight Units: Lb
    3. session_swing: Dynamic Trial Identifier
    4. user: Static Trial Identifier
    5. Check "Subject Specific" next to highest_playing_level, hitter_side, bat weight/length, and Click "Apply".
  7. CMZ files may take a while to build. Check the status bar in the bottom left hand corner of the interface for the build status. After the files are built, check that the Library Path dialog is set correctly and hit "Load" in the Load Library dialog.

Data

The OpenBiomechanics data set provides cleaned c3d files with 3D kinematic data for 47 body markers, 22 lower limb and pelvic markers, and 25 head, upper limb, and trunk markers; there are also 10 markers placed along the bat. Important metadata that is being considered are highest_playing_level, the level of competition that the subject is currently competing at, and blast_bat_speed_mph_x, the bat speed at contact as measured by Blast Motion sensor in miles per hour. For this tutorial, only the baseball_hitter data set will be analyzed.

To follow along with this tutorial, please go complete the Building CMZs Files tutorial. If you would like to skip the build CMZs Files and MetaData tutorials, you can:

  • Download this pre-built CMZ workspace.
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