## Translation of geometric models ArchiCAD-Patran

For analysis of the geodesic shell for strength and stability, modern powerful FEM software systems (Patran/Nastran) can be used. However, this requires the conversion of the geometric model of the shell into a format that Patran/Nastran can understand.

Therefore, special translators were developed that convert a geometric model from the ArchiCAD program into a geometric model in the format of Patran/Nastran. This program performs the following functions: creating a geometric model based on the original geometric model from the ArchiCAD program (ArchiCAD - obj file), creating a file containing the geometric model in the Patran database format (Translator - ses file).

An OBJ file consists of a sequence of polygons separated by spaces. All lines ends with eof symbol. Each polygon consists of a sequence of vertex numbers separated by spaces. The vertex number refers to its X, Y, Z coordinates in Cartesian coordinate system. The required output file must contain calls to the Patran Command Language (PCL) functions that generate the corresponding surfaces.

*Graphical user interface translator v 1*

*Class I1; 3. Six triangles are connected by six edges.*

*In ArchiCAD.*

*In Patran.*

The translator of the double-contour geodesic shells translator v 2 was also developed. It accepts a geometric model of a double-contour geodesic dome with plates and rods, and create session file Patran for generating a model of a double-contour geodesic dome.

To ensure the translation of double-contour geodesic shells from ArchiCAD to Patran, variants of parametric objects were developed, in which the rods are represented by the operators of the GDL slab (A - options for analysis). Parametric objects in which the rods are represented by lin_ operators are suitable for design.