How to make full size div on a gltf plane geometry

Hello,

I have created a plane in blender and exported it in gltf. I want to make a div that is the same size as that plane. I was trying to do it by figuring out the width and height of that plane in pixels by multiplying the scale.x and scale.y values to 3779.5275590551 which I got from converting 1m to pixels from online converter… Still the div is not on the same height and width as the plane.

Reference Image:
image

Kindly help me with this.
Thank you.

idk how that site is converting the meter to pixels but you can measure how many pixels are equal to 1 meter since it depends on how far is camera on z axis and fov of your camera.

viewport height in meters = (Math.tan(camera.fov)/2)*((2 * camera's position on z-axis)*Math.PI)/180

pixels = window.innerHeight/viewport height in meters //this will give you the 1meter to pixels conversion
 

I haven’t tried this, but this should work ig if you jus want meter to pixels convesion