Hi everyone,
I'm having an offset problem while developping an MR application, here are the specs :
- Motive / OptiTrack cameras
- Unity with OptiTrack package
- Varjo XR-3 HMD with a group of markers (considered as a RigidBody, not an HMD in Motive)
To check the tracking data, I got the CAD model of the XR-3 on Varjo site and did a quick photogrammetry scan of the HMD with the markers to create a reference model to display in Motive. I did a simple model of a rigidbody marker set too. I set the pivot point from this page : https://developer.varjo.com/docs/get-st ... y-tracking. The transforms of the hmd and marker set are correct in Motive and Unity.
When visualizing the 3d model of the marker set in augmented reality, there is an offset that changes depending on the point of view. I implemented a tool to set a global offset, a camera local offset and other tweaks but it didn't fix the issue.
I've contacted Varjo support and they suggested to use a Varjo Tracking plugin (now set on SteamVR in Varjo Base by default but I don't use SteamVR code in the application), I don't think it would fix the problem as the tracking works well through the OptiTrack Unity package. Could I have missed something on the Motive side ? What can I tweak / explore to find the origin of the problem ?
Thanks, best regards
Aurélien
Visual offset in Mixed Reality application (Motive / Unity)
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MatthewSilveira
- NaturalPoint Employee
- Posts: 5
- Joined: Wed Jan 31, 2024 3:42 pm
Re: Visual offset in Mixed Reality application (Motive / Unity)
This is a pretty complicated problem, I'm going to try and explain what I think is happening based off of the description.
You might need to manually change the pivot point of the object that you are interacting with in VR. When you create a rigid body, the centroid is placed in the geometrical center of the object's markers. This is not necessarily the center of the object, or the focal point of the Varjo headset (in between the eyes, equidistant from the center of the eye glasses and the top and bottom of the Varjo headset). The offset for a headset is tricky to play with, since this is what will often cause the motion sickness when people use VR. You can select the HMD markerset in Motive and use the Advanced Properties to move the pivot point of the headset.
LP Research has created a plugin for Motive that works with the Varjo headset, and we also sell Varjo clips that are specifically made to get that offset, although I do not believe they are on the website, you'd have to contact a sales representative.
https://varjo.com/vr-lab/optitrack-art- ... o-steamvr/
You might need to manually change the pivot point of the object that you are interacting with in VR. When you create a rigid body, the centroid is placed in the geometrical center of the object's markers. This is not necessarily the center of the object, or the focal point of the Varjo headset (in between the eyes, equidistant from the center of the eye glasses and the top and bottom of the Varjo headset). The offset for a headset is tricky to play with, since this is what will often cause the motion sickness when people use VR. You can select the HMD markerset in Motive and use the Advanced Properties to move the pivot point of the headset.
LP Research has created a plugin for Motive that works with the Varjo headset, and we also sell Varjo clips that are specifically made to get that offset, although I do not believe they are on the website, you'd have to contact a sales representative.
https://varjo.com/vr-lab/optitrack-art- ... o-steamvr/