Chair that transforms into a stepladder

Created according to the drawing. The drawing from here was taken as a basis https://derevyannyj-stul-stremyanka-chertezhi-98-foto.mizmet.ru/?  yj gthth , but reworked.
The drawing from the Internet and the corrected drawing (in AutoCAD-2010 format) are in the archive

The archive also contains FBX, OBJ files and corona and vray material libraries.

Stepladder size: 430x590x870 mm
Chair size: 430x450x870 mm

The model consists of only quadrilateral polygons.
Chair:
Polys: 15996
Verts: 16102

Ladder:
Polys: 15996
Verts: 16102

Since both objects have the same number of polygons and vertices, modifiers like Morfer can be used.
The Pivot Point of the movable part of the chair and stepladder is installed at the turning point - you can easily manually transform the chair into a stepladder and vice versa

Those who work in V-Ray version lower than 3.1, be careful, in the materials in the BRDF section there is Microfaset GTR (GGX), if your version is older than 3.1, then the BRDF field will be empty. Select Blinn, Phong or Ward - what is preferable for you.

For Corona render, it is recommended to install version no lower than 1.5, since the glossiness of materials is configured taking into account PBR.