How to adjust takeoff altitude?

[mikerosz]

I am a little confused on how to adjust controls for vx, vy, vz. Especially takeoff height, is there a way to make it fly a certain height from takeoff. I was using the sample_tracking file. And I was trying to detect gutters with the bottom camera and it did so successfully, but the drone flied straight up. I don't know why. ANy help would be appreciated? I am trying to get the drone to detect the gutter and fly straight from one end to the other using the bounding box you made.