How would you make a tunnel effect like in this video? https://www.youtube.com/watch?v=_T0LQZ7HdIE
First option:
Convert your 2d scene to a 3d scene, and position all the (flat) drawn tunnel components in 3d space (create a “real” tunnel).
Then animate a camera to fly through the tunnel.
Second option:
Model tunnel in Maya, and texture it with your tunnel textures. Import 3d object in Harmony.
Third option:
Model tunnel in any 3d application. Texture the sides with your tunnel drawings. Add lighting, and animate the sequence in the 3d app. Render out the sequence, and import as an image sequence in Harmony.
The third option gives you the best performance and most options as to rendering. Rendering will be quick, depending on the settings.
The first option is the slowest, both in performance, but also in setting up the tunnel (depending on complexity: I would NEVER think about creating a tunnel of that complexity in Harmony - just a waste of time in my opinion, and renders poorly: look at all the seams!).
for the first option, how would you animate the camera to do that?
You animate the camera to fly through the tunnel.
https://learn.toonboom.com/modules/camera-motion2/topic/animating-the-camera2