vrcalib

Cardboard viewer calibrator. Not an official Google product.

Viewer profile

How to calibrate
  1. Scan the phone QR code (right) with the phone. Enter its PPI if asked and tap Start, then put the phone in the viewer.
  2. Measure with a ruler and enter screen-to-lens, inter-lens and tray-to-lens distances.
  3. Fine-tune inter-lens and tray-to-lens until each red dot sits in the middle of its lens and the two images fuse.
  4. Tune k1, then k2, until grid lines are straight right to the edges. Lines bowing outward (pincushion): raise k1. Bowing inward (barrel): lower it. k2 mostly affects the outer edge.
  5. Red visible inside your view means a field-of-view angle is too small: raise the angle on that side (outer, inner, bottom, top) until the red goes past the edge of the view. Red that won't go away is where the screen itself ends.
  6. Scan the export QR code with a Cardboard app.

Tab / Shift+Tab move between fields. ↑ / ↓ change a number by 0.5 mm, 0.01 (k) or 1°; hold Shift for ×10.

Viewer
Geometry
screen lenses eyes Screen to lens Inter-lens Top view tray Tray to lens tray Tray to lens lenses centred on the screen Front view (from your eyes)
Distortion
Field of view (left eye)
Input

Phone

Scan with the phone's camera to open the viewer. It updates live as you edit.

With the viewer fullscreen, measure the lit screen along its long side, edge to edge. The phone works out its pixels per inch from this, so nobody needs a spec sheet.

Export

Scan this QR code with a Cardboard app to use the profile.