The translation attempts to take into account other material settings in ArchiCAD, apparently. If you duplicate the default red in ArchiCAD and in this new material, slide your ambient and diffuse all the way to the right, reflection and specularity all the way to the left, in ArchiCAD before exporting, you'll get 249 in Artlantis. (I did all of them in a test - might only be the specularity, e.g., that matters.)
Experiment with the original and a changed 'red' and examine the Artlantis parameters to see how it changes the color and reaction to the light.
A "red" ArchiCAD wall (default 'red' material) is not a pure red RGB wall - it is a wall with a particular red shader applied, responding to light in a certain (limited, compared to advanced renderers) way. It makes sense for Artlantis to try to interpolate this shader to something approximately in the Artlantis view of shaders.
Not saying it is 'right', just what it is.
😉
Cheers,
Karl
One of the forum moderators
AC 28 USA and earlier • macOS Sequoia 15.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB
