How to improve the quality of a 3d model using SceneKit?

Question

3D

Hello! Such a thing:
We wrote a mobile application for iOS on Swift.
The task was this: to screw a 3D model into a mobile application of the same highest quality as on a computer.
3D model - about 15000 polygons. The model is simply "1080p FULL HD". We want to achieve the same quality in the mobile application.
But we encountered such an unpleasant moment that the model on the phone looks "360p", that is, the quality and detail here are noticeably worse than we need. And we need "1080p FULL HD", and this is extremely critical
. Dear colleagues, please tell me how to fasten the model without losing quality?
As one of the options, we thought to write a part of the code in C # in Unity, run the model through Unity, then compile it for iOS, and maybe this way we will be able to achieve the desired quality on mobile phones.
In general - who has any thoughts on how to convey the original quality - we would very much like to listen!
Thank you!

Answer 1

https://docs.unity3d.com/560/Documentation/Manual/...
Fantastic quality only included.