Affected version(s): ARCHICAD 19, 20| Severity: workaround applicable | ID: 208529
Multisample anti-aliasing (MSAA for short) is a technique used in computer graphics to improve image quality. This technique samples multiple locations within every pixel, and each of those samples is fully rendered and combined with the others to produce the pixel that is ultimately displayed. As a result, slanted lines appear smoother on the screen giving a better image quality. MSAA is built into ARCHICAD (referred simply as Antialiasing on the interface) to achieve the best image quality at all times:
An image displayed with Antialiasing however requires multiple times more resources of the Graphics Processing Unit (GPU) than without Antialiasing. This is why it can cause performance issues on hardware that are not equipped with a professional GPU, but drive a large resolution display. As an example, the newer 21,5″ iMacs with 4K display (4096 x 2160) are not equipped with a dedicated GPU, but only an Intel HD or Intel Iris Pro unit, that are not sufficient for antialiasing images on the 4K resolution screen.
To avoid performance problems, Antialiasing on such machines is turned off in ARCHICAD 20 and newer. In the work environment, you will be prompted with Warning: Antialiased drawing has been automatically disabled due to insufficient video card resources.
On 21,5″ iMacs with 4K display it is possible to turn Antialiasing back only through the macOS Preferences file of ARCHICAD. To do so follow the steps below:
- in Finder select Go menu
- press and hold the alt (option) key to make Library visible in the Go menu
- select Library and navigate to: ~/Library/Preferences/com.graphisoft.AC-64 20.0.0 INT v1.plist (note that your plist file name might differ depending on your AC version & language version)
- Open the selected .plist file with a plist editor application (e.g.: PlistEdit Pro, Pref Setter, Xcode)
- Navigate to the OpenGL folder and select the Antialiasing Mode key
- Change the value to 1 to force ARCHICAD to use Antialiasing with your Intel GPU
- The change takes effect only after ARCHICAD is restarted