Topper Pimpi, relax! You're not going to fail because of that
Hope so ! :-)
The height of an imaginary screen placed at the end of the TODR
Take Off Distance Required...by the A/C taking of at that specific weight, configuration, environmental condition. Let's say that if you take off with a small cessna 150 from a 3 km runway, your screen may be just after 500 m.
So it's clear to me that this "screen" is an imaginary hurdle that can be between anywere from just after brake realase (if U're an heli or a JATO acft) to the end of the clearway.
The take off surface seem to be referred as the reference for the take off vertical profile, in fact for example
JAR 25.1 11 Take-off path (a) The take-off path extends from a standing start to a point in the take-off at which the aeroplane is 1500 ft above the take-off surface,
.
Be at 1500 ft by the end of the runway can be pretty hard to achieve !
I feel a little better now :-)