as seen in holoduke plugin by vet:
PHP Code:
new Float:Vel1[3], Float:Vel2[3]
velocity_by_aim(id,module,Vel1) //module is how fast you want it to be
pev(id,pev_velocity,Vel2)
Vel2[0] += Vel1[0]
Vel2[1] += Vel1[1]
Vel2[2] += Vel1[2]
set_pev(id,pev_velocity,Vel2)
does that help?