Can ARCore be used to measure object, room, structure or distances between points in an area that aren't in the same frame?
Ian M partially answers the first part of your question with this answer. Here's how you might do it:
Pose startPose = startAnchor.getPose(); Pose endPose = hitResult.getHitPose(); // Clean up the anchor session.removeAnchors(Collections.singleton(startAnchor)); startAnchor = null; // Compute the difference vector between the two hit locations. float dx = startPose.tx() - endPose.tx(); float dy = startPose.ty() - endPose.ty(); float dz = startPose.tz() - endPose.tz(); // Compute the straight-line distance. float distanceMeters = (float) Math.sqrt(dx*dx + dy*dy + dz*dz);