# How to calibrate and track the movement of a non-stylus model in IGT
**URL:** https://discourse.slicer.org/t/how-to-calibrate-and-track-the-movement-of-a-non-stylus-model-in-igt/7517
**Category:** Support
**Created:** [July 11, 2019, 2:55am UTC](https://discourse.slicer.org/t/how-to-calibrate-and-track-the-movement-of-a-non-stylus-model-in-igt/7517 "2019-07-11T02:55:42Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Christopher\_Ji](https://discourse.slicer.org/u/Christopher_Ji)
#### Post date: [July 11, 2019, 2:55am UTC](https://discourse.slicer.org/t/how-to-calibrate-and-track-the-movement-of-a-non-stylus-model-in-igt/7517/1 "2019-07-11T02:55:42Z")
Hello,
I’ve tried attaching the model of i.e. a human’s head with a NDI rigid body, from which I could track the movement, or the wobble of the model on 3D Slicer. However, this is not quite accurate, is there any further improvements or calibrations?
Thank you!
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### Author:  [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [July 26, 2019, 3:27am UTC](https://discourse.slicer.org/t/how-to-calibrate-and-track-the-movement-of-a-non-stylus-model-in-igt/7517/2 "2019-07-26T03:27:33Z")
What tracker do you use? NDI Polaris, Vicra, …? How did you fix the rigid body to the head (rigidly, using screws or pins, or just loosely with headband, tape, etc)? How did you obtain the head model (CT, MRI, surface scanner, …)? How did you register the reference body coordinate system to the head model coordinate system?