Our debate on design rationalism has burst out of its container.
I present here the Peugeot 405 and Citroen BX together with some highlighted lines marking out their main features. I have extended the lines to see how they relate at a hypothetical level.
And now here are the annotated cars.
The Peugeot is visually simpler in that it lacks a third side glass. The Citroen has that complex area at the C-D pillar plus the louvres underneath. What adds a considerable amount of visual noise is the vertical line where the black rear bumper meets the rear wheel arch bodywork. An entirely different solution is needed to eliminate that unwelcome vertical element. I believe that the use of large radii all over the 405 also reduces the amount of “information”. Research shows that points attract the eye. Turning sharp corners into radiused corners defeats that effect and make it harder for the eye to fall on any one place.
My conclusion is not that one of these cars is better than the other. Frustratingly, I like them both a lot. What I have learned or what I propose is that the BX is not design rationalism but more “technicalesque”. Whether deliberately or not, Citroen and Gandini did a car that played up the technical elements of the design, adding details that stress the car’s mechanical character. The 405 plays this down in the search for smoothness at all scales. It’s classical to Citroen’s determined Modernism.