OpenSees does not compute reactions automatically because this can be a time consuming process--OpenSees assembles reactions over all nodes in a model, not just over the nodes that are constrained. When performing response history analysis, assembling reactions is likely not something you want or need to do at every time step. You probably just want … Continue reading Trying to Get a Reaction
You can record section response in a frame element if you know the section number, or integration point, of the section whose response you would like to record. This is straightforward for distributed plasticity integration such as Lobatto or Legendre where section number 1 is at end I of the element and section number N … Continue reading Section X
Polymorphism is what makes OpenSees, and other object-oriented software, flexible and extensible. With polymorphism, you can program to an interface, not an implementation. You see this approach all over OpenSees--elements don't care how materials compute stress and tangent (more here); integrators don't care how the elements form resisting force and tangent stiffness (more here); and … Continue reading Polymorphic Pitfall
Update September 13, 2021: The issue described in this post has been resolved as of OpenSeesPy version 188.8.131.52. Python is one of the best things to happen with OpenSees. Unfortunately, the break from Tcl has not been squeaky clean. A very sticky transition point has been element recorders. When we wrote the internal setResponse functions … Continue reading Recorders Not Recording?