RF-FORM-FINDING | Input
The form-finding function can be activated in the General Data dialog box, Options tab. Prestresses (or geometrical requirements for members) can be defined in the parameters for surfaces and members. The form‑finding process is performed by calculation of an RF‑FORM‑FINDING case.Steps of the working sequence:
- Creation of a model in RFEM (surfaces, beams, cables, supports, material definition, etc.)
- Setting of required prestress for membranes and force or length/sag for members (e.g. cable)
- Optional consideration of other loads for the form-finding process in special form‑finding load cases (self‑weight, pressure, steel node weight, etc.)
- Setting of loads and load combinations for further structural analyses
Membrane Roof and Cable Net Structures, Deformation Animation in RFEM with RF-FORM-FINDING Add-on Module.
With the activated option "Topology on form-finding shape" in the Project Navigator - Display, the model display is optimized based on the form-finding geometry. For example, the loads are displayed in relation to the deformed system.
- I have modeled a structure made of outer and inner cables as well as membranes, and get a message about instability or the error message "Jacobi matrix is not positive definite" in the RF‑FORM‑FINDING add-on module. What should I do?
- A cable structure model created in RFEM 5.13 cannot be calculated in the current version of the program. The program displays a message that "Stiffness matrix is singular," although it could be calculated in the original version. How can I fix this?
- How is it possible to create the cutting pattern geometry for a decorative sticker on a biaxially curved membrane roof?
- Why does the form-finding not work for the "Cable on Pulleys" member type?
- How are the properties of the elasticity and shear modulus of a membrane fabric with the usual force/length syntax transformed into the general force/surface syntax to be entered in RFEM?