Karbandi is a type of covering that consists of a combination of arched lintels (narrow arches). And it can be applied to roof coverings in various ways. One of the methods that Iranian architects have used to build Chapireh is the use of karbandi. Which is used in various parts of corner making, including cornering or Shekanj. And the various contexts in which the dome has been implemented have enabled Karbandi to create architectural beauty in addition to structural behavior. And in designing the layout on its grounds; determining the connection points and theoretical and practical geometry is considered a vital step. Because each karbandi has a certain theoretical and practical geometry. In the present study, the connection points and theoretical and practical geometry in two fields of square and rectangular karbandi implemented in corner construction will be examined. This research is a qualitative research type, which is done using a descriptive-analytical method and the necessary information was obtained through library studies and sample analysis. Therefore, in order to achieve the results of this research, the use of corner construction in various buildings was first examined. The plan and three-dimensional view of each of the structures were examined and analyzed in terms of practical and theoretical geometry. The results of the research show that a) corner construction can be divided into two categories: shape and field. In terms of shape, it can be applied to two categories: square and rectangle, and in terms of field, it can be applied to two categories: 2) The theoretical and practical geometry of cornering in the field of squares and rectangles is not the same. For a two-dimensional drawing, the number obtained from counting the butterflies must be added to the number 4, but for three-dimensional modeling, there is no need to add the number 4. 3) The theoretical and practical geometry of the connection points are not the same. To implement and model a karbandi, the connection points (d) obtained from counting the rows must be subtracted from the number 1 because when we do not subtract the number 1 and start implementing and drawing, an additional butterfly row is created in the karbandi, which is not correct.
