I have been using a grid material for the floor in many of my tool scenes. I set the interval to 1, which is good for XR, in that it corresponds to 1 meter.
const floorMat = new BABYLON.GridMaterial('floorMat', scene);
floorMat.majorUnitFrequency = 1;
floorMat.mainColor = new BABYLON.Color3(.45, .45, .45);
floorMat.lineColor = new BABYLON.Color3(.9, .9, .9);
It would be nice if it were also PBR material as well, or at least the pieces I use. I could probably get close with thin instances of squares just above a large square of a different color, but of course it also forces the floor to be square. I was using a circular floor, so that corners are not really pronounced. That works pretty good for XR, since the camera is close to the ground.
Any prospects?