[ReD_HunTeR]

You have to use MapAndreas plugin for that, velocity is not for that type of purpose.

Код:

new Float:ox, Float:oy, Float:oz, Float:mz;
GetPlayerPos(playerid, ox, oy, oz);
MapAndreas_FindZ_For2DCoord(ox, oy, mz); //this here is to find the ground coordinates you have to use mapandreas plugin
if(mz != nz) return SCM(playerid, COLOR_LIGHTRED, "* You can't plant seeds in air."); //If ground value doesn't match with the players Z coordinates returns error

https://sampforum.blast.hk/showthread.php?tid=120013