Issue Description
In Archicad version 28 and below, when saving views from the 3D window, Archicad will use the screen resolution of the monitor to determine the DPI (dots-per-inch resolution) on the Layout. The maximum size of the image is limited by the maximum size of the monitor. To get a higher resolution image you would need to use the PhotoRendering palette to define an output with higher resolution.
Solution
Using the most current version of Archicad (29 or higher) will allow you to customize the resolution of 3D Views placed on Layouts.
To learn about how to set the DPI resolution for 3D Views to improve output quality without affecting the size of placed drawings, follow the help guide here.