> For the complete documentation index, see [llms.txt](https://docs.enercalc.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.enercalc.com/e3d-user-manual/model-entities/toc161394020/toc161394022.md).

# Degrees of Freedom (DOFs)

How to understand the six nodal degrees of freedom and choose an appropriate model type for analysis.

Each node may have a maximum of six global degrees of freedom (DOFs) associated with it. They are three translational DOFs along the global X, Y, Z directions (Dx, Dy and Dz) and three rotational DOFs about the global X, Y, Z directions (Dox, Doy and Doz).

Some of these DOFs may not be available depending upon the type of a model.

For example, the model type “2D Truss” has Dx and Dy available and Dz, Dox, Doy, Doz unavailable or suppressed; while the model type “2D Plate Bending” only has Dz, Dox, Doy available and Dx, Dy, Doz suppressed.

You may always use the model type “3D Frame and Shell” to analyze any structure, however, time and computer memory may be wasted if a simpler model type can be used instead. You may choose the appropriate model type by command Analysis > Analysis Options.

Six nodal displacements associated with 6 DOFs are output for each node. For restrained or unavailable DOFs, the program outputs the corresponding displacements as zero. Nodal displacements should be the first thing to check for when determining result correctness since the solution is displacement-based. If the displacements are wrong, nothing else will be correct.


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