Coplanar (or flush sliding) doors are sliding doors that form flat wardrobe front. Furniture with such doors is utilitarian and elegant.
All* existing coplanar door mechanisms require special structure of wardrobe body. They also require a significant gap above or under the doors for brackets which hold the doors weight. The second requirement makes practically impossible** designs in which wardrobe body frames its doors. That's why coplanar doors always cover wardrobe body in current designs. If you try to make a built-in wardrobe, you will have to accept thick gaps for the brackets mentioned above.
«Vesna» has a different principle of operation and lacks these limitations. Particularly, wardrobe doors can be framed by its body. It makes possible to have a build-in wardrobe with coplanar doors and invisibly small gap around them.
"Vesna" mechanism is mounted entirely inside a wardrobe. The mechanism is an independent unit and allows to make furniture with any amount of doors starting from one.
The mechanism positions doors with the same accuracy as the barrel hinges do, which allows to have small and accurate gaps around the doors.
"Vesna" requires almost no usable space in a wardrobe. A cut inside a shelf in a picture below shows a space that has to be reserved for the mechanism.
Bortoluzzi Sistemi is the only big manufacturer of furniture coplanar doors I know. It also holds a set of patents related to coplanar door mechanisms.