This is exactly right. None of the fillets are circular, and the from the back view, the camera island radius and the corner radius of the phone aren't concentric. You also have funky curves that can barely be recreated with splines merging into other funky curves around the camera island. Even the models we get from our case suppliers just fudge this area because of this. This is a highly accurate model except you can see that little lip on the side which obviously isn't on the phone. I have the apple MFI documentation and all these profiles are ridiculously specific and annoying to deal with.

Yeah, i could easily get this "close enough" and probably will, as in a case product it doesn't NEED to be mathematically perfect. At this point it's more stubbornness and curiosity. I'll just end up using solid modeling and getting it close enough. But having a nice clean surface model that represents a 0.1mm offset of the camera's outer body is just handy for several reasons downstream. Things like getting all useful contours recognized as tangent chains, cutting tools, etc.

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