Modeling Detail on round Surfaces using Retopo

For my latest work, a scene with a HH-65 Dolphin in it, I found a great way to model detailed shapes (like windows, little holes and similar things) onto a round and complex surface without getting ugly crases and similar things on the surface because of edgeloops destroying your round shape.

What I did:

1. I modeled the basic shape of the helicopter, totally free of any detail but with a lot of care to get a nice surface with relatively few vertices.
2. I added a second object, activated retopo and started to model all the plates, windows, door-frames and similar objects onto this surface. These parts got the nice rounded shape of the object below, but had a topology fitting to the shape of the detail and having a lot more polygons than the original model.

3. 

   I deactivated retopo and extruded and fattened the plates/windows to give them some thickness and realistic edges. The result was a nice, realistic and detailed model with the nice shape of the original sub-model.

I found this technique very useful and therefore wanted to share it with you.

I also recorded some video of the basic workflow using some aircraft canopy as an example.

I hope this helps some of you who want to model aviation models or similarly detailed things (like cars, trains, space ships, rockets, …).