I wanted to be able to put my 32oz Nalgene bottle into the cupholder of my 2015 Hyundai Sonata so I designed this OpenSCAD to create an adapter for my vehicle.  Hopefully others can use it to create files for their own vehicles or cupholders.

The Hyundai adapter fits cupholders with dimensions of 74mm-82mm over a height of 72mm.
The Nalgene dimensions I used are 92mm (with a 2mm tolerance) and 50mm height.

The pictured holder is printed in PLA using .3 layer height.  I normally cut off about 30mm from the bottom of the holder to save time and material and have not had any issues with it holding the bottle in the car.  No supports needed as long as the transition height is enough to keep the angle higher.

UPDATE: 11/15/2022 - I recently needed to generate a new model for a couch with cupholders and found an issue with the transition calculation.

UPDATE: 5/16/2023 - Added a '23 Hyundai Palisade model that fits the swing out cupholders in the center console.

UPDATE: 6/29/2023 - Updated the '23 Hyundai Palisade model as it was just a bit too loose and rattled, this one fits more snugly.