I understand waypoints very well in two dimensions. If I set up a square box of 4 waypoints, the actual flight route will be wide of the square lines and passing over each waypoint is designed to make camera movements and flight path smoother. So the actual path is "wide of the square." No problem once you understand.

But what about vertical path. If I set a waypoint at an altitude of say 10 feet. Then fly a short distance at the same altitude and set a second waypoint at the same altitude. Then fly a short distance and up to say 100 feet and set the 3rd waypoint. Will the actual flight path be similarly "wide" causing the drone (Mavic 3 in this case) to descend before the second waypoint in order to smooth the flight path toward the 3rd waypoint? And if so, w/o obstacle avoidance, won't we risk flying the drone into the ground or water if over, say, a lake?

Since the waypoint map in the dji fly app is two dimensional, you'd get not visual indication of a zero altitude condition.

Hello, there. Sorry for the inconvenience. About your question, could you please explain this part Then fly a short distance and up to say 100 feet and set the 3rd waypoint. Will the actual flight path be similarly "wide" causing the drone (Mavic 3 in this case) to descend before the second waypoint in order to smooth the flight path toward the 3rd waypoint? for me?
According to your description of the waypoint and height, we found some information for you. Hopefully, it will help you in some ways.
After the Waypoint is marked, the aircraft will record the flight altitude, nose direction, gimbal pitch angle, and other data at this point.
If the route trajectory is a smooth curve between Waypoints, the height of the flight segment trajectory will be lower than the Waypoint height. Please pay attention to the obstacles below.
Before flying, please observe the surrounding environment to ensure that the route is not blocked. The first thing to do is to put the brake button during the flight.

DJI Wanda Posted at 4-17 19:41
Hello, there. Sorry for the inconvenience. About your question, could you please explain this part Then fly a short distance and up to say 100 feet and set the 3rd waypoint. Will the actual flight path be similarly "wide" causing the drone (Mavic 3 in this case) to descend before the second waypoint in order to smooth the flight path toward the 3rd waypoint? for me?
According to your description of the waypoint and height, we found some information for you. Hopefully, it will help you in some ways.
After the Waypoint is marked, the aircraft will record the flight altitude, nose direction, gimbal pitch angle, and other data at this point.

I think you've confirmed my hypothesis.

When crating a waypoint mission, using arc (not polygon) routing ... I could fly to a point with an altitude of 10 feet, say, and set waypoint 1. Then I could fly 50 feet horizontally and set waypoint 2 at an altitude of 10 feet. Then I could fly 15 feet in the same direction and ascend to an altitude of 100 feet to set the third waypoint.

Now, when I instruct the drone to fly the waypoint mission ... it would fly to the first waypoint and point itself toward waypoint 2. It would fly to waypoint 2. And then it would ascend to waypoint 3. But because we are flying an arc waypoint mission, the drone would descend between waypoints 1 and 2 attempting to smooth the altitude change at waypoint 2. This could cause the drone to descend to ground level between waypoints 1 and 2 if obstacle avoidance was off. I think if obstacle avoidance was on, it would interrupt the mission.

So if I understood your response, you've confirmed my hypothesis. As always watch for potential obstructions during your waypoint planning and in this case, WATCH OUT FOR ALTITUDE CHANGES where the ground could be the obstacle. And ALWAYS (or usually) fly with obstacle avoidance ON.

Thank you.

charles.h.porter@comcast.net Posted at 4-18 10:40
I think you've confirmed my hypothesis.

When crating a waypoint mission, using arc (not polygon) routing ... I could fly to a point with an altitude of 10 feet, say, and set waypoint 1. Then I could fly 50 feet horizontally and set waypoint 2 at an altitude of 10 feet. Then I could fly 15 feet in the same direction and ascend to an altitude of 100 feet to set the third waypoint.

Thank you for your reply. We are glad if the information is helpful to you. Please let us know if you have any questions.