DefaultHeadHeight setting in camera data provider profile causes misbehaviour

[FejZa]

XRTK - Mixed Reality Toolkit Bug Report

Describe the bug

The DefaultHeadHeight setting is causing issues in my WMR hand tracking implementation. Upon research it seems to me, the setting is not doing what it's supposed to do or it's unclear to me what problem it is trying to solve.

What I understand it should do
The default head height should only be applied, if the target device does NOT provide head height itself, e.g. Oculus GO or other 3DoF devices. So the setting should NOT affect HoloLens 2 as I understand.

What it does it seems
The setting gets applied as soon as the target device is stereoscopic, no matter whether it is 6DoF or not and provides head pose natively.

The properties docs say

/// <summary>
/// The default head height when a platform doesn't automatically set it.
/// </summary>
float DefaultHeadHeight { get; }

So it should only do anything when a platform doesn't automatically set it, which HoloLens 2 does. So I figure this is a bug.

What I observe

I set the default head height to 1.6, following happens

• Run application while seated -> Camera Y-Position = 1.6 (this does not make sense as I am not 1.6 above floor when seated)
• Now stand up -> Camera Y-Position ~= 2.2 (this does not make sense as I am not 2.2m tall)

To Reproduce

• Set the default head height to e.g. 1.6 and run either on device or using holographic remoting
• Observe the camera transform position as you move around

Expected behavior

• The setting is ignored on HoloLens 2 and any other 6DoF device.

Actual behavior

• The setting is not ignored