Fologram uses the same anchor-based system to precisely locate models on the Quest as on the HoloLens or mobile devices. However, unlike these devices, the Quest does not provide native QR code tracking support and so the position of each Anchor in physical space must be defined manually.
Adding Anchors to your Model
Use the
XRMarker command to define the location of your Anchors relative to your Rhino geometry as you would if working with the HoloLens or Mobile devices. For help determining the optimal distribution of Anchors, see Model Placement. Physical Setout
Instead of setting out printed QR codes in physical space at the location of your Anchors, you can use masking tape and a pen to carefully indicate the coordinate and label of each Anchor. If you are using Anchors for the first time, we recommend using a tape measure and setting out two points an exact known distance apart as any imprecision in the setout location will introduce corresponding imprecision in the model.
Moving Anchors
We recommend using your Quest controller for precise movement of Anchors.
Start a new Fologram session and connect your Quest. When you first load the model, use the tap and point mechanic to locate it approximately in your space. Next, to locate the model using your anchors:
- Open the Fologram Menu on the Quest
- A list of Anchors in your model will appear at the top of the table in the menu. Tap the anchor you want to place.
- A cross hair representing the anchor will appear in front of you. Grab the cross hair and move it to align with the corresponding physical mark in your space. The Anchor is now located and will be used for drift correction.
- Repeat steps 1-3 for each Anchor you wish to place. After placing each Anchor you may notice your model adjusting position and rotation to match the new coordinate space defined by the anchors.
Refining Positions
The position of Anchor crosshairs relative to their physical marks can be used to identify any drift or “swim” on your space that can be expected overtime. Anchor positions can be modified at any time to correct for this swim by grabbing the crosshair and moving it back to the correct physical location.
If you are experiencing dramatic misalignment between Anchors and their physical positions and refining the anchor position does not resolve this, see troubleshooting tips below.
Repeated Placement
The labels and coordinates of all manually placed anchors are saved automatically in Fologram for Quest. Any Anchors that have been manually placed in your space will persist across sessions and models. To use the same set of Anchors in a different Rhino model, simply ensure that the positions and labels match those that have been placed previously.
Resetting and Removing Anchors
To reset placed Anchors in the current model, open the Fologram Menu and then press Recentre. These Anchors can then be placed again by selecting them from the table in the Fologram Menu. To reset all previously placed anchors, clear your physical space history as outlined below.
Precision and Placement Troubleshooting
In a typical workspace consisting of many visual features, two Anchors positioned 8000mm (26’) apart should be enough to reduce observed drift to under 10mm (1/2”). To verify this in your own space, you should conduct the Precision Test. If you are still experiencing significant drift you can try the troubleshooting steps below.
Clearing Tracking Data
Moving objects and other changes in your environment can adversely affect tracking on the Quest. You can often reduce drift by clearing the physical space history on your Quest and forcing the device to build up new SLAM data from your physical environment.
To clear your physical space history:
- Press / on your right Touch controller to pull up your universal menu.
- Select Library, then select Settings.
- Select Physical Space then select Boundary.
- Select Clear next to Clear boundary and space scan history.
- From the Space Setup menu, select Setup and follow the instructions to rescan your space.
Checking Coordinate Spaces
Fologram requires the relative coordinates of Anchors defined in your Rhino model to exactly match the relative positions of the same Anchors defined in physical space in order to perform drift correction.
To identify if there is an obvious discrepancy in Anchor positions you can use the
Distance command in Rhino to measure distances between pairs of anchors, then use a tape measure to confirm that the physical distance matches. While this method will not tell you how to improve physical anchor positions, it will help identify mistakes. We recommend beginning with only two Anchors set out with a tape measure, and introducing additional markers if metrology is reliable.