C_SCAN

I want to point down and know the altitude of my entity on relation to the terrain.
I think what i need is c_scan but i am having hard time to dechiper the manual.
Can the cone be of radius zero?
What is Euler angles?
Please give me some example and explain how to change the example.

Thanks in advance

It is c_trace, not c_scan that you are looking for.
In the manual in the topic c_move, there is a movement code with c_trace used to know the altitude of the entity.
That should you give at least a better idea of how it should work.