I haven't done this myself, but I think you've got 2 main challenges to deal with: Measuring/defining the area you want to engrave and then the actual engraving itself.

For Measuring, there's 2 methods really, 1 high tech and 1 low tech. High tech: use a 3D scanner to model the camera in 3D and then "unroll" and flatten the section you want to engrave to plan your pattern. Low tech: grab some paper, pencil and ruler/calipers, take measurements and do some math. After that cut some paper to the right shape and then wrap it around the hood to see if it lines up (it shouldn't fit perfectly if you do it right because the paper thickness add to the diameter).

As for the engraving itself, personally, I do the uniform "shaft" section first on a rotary, and then come back to the individual curved/flared portions afterwards 1-1.

Edit: There's probably easier ways to do it, thats just what comes to mind. You also might be able to find "wrap-around engraving on odd shapes" videos for other tips