Have you ever received an instability warning when running a three dimensional RISA-3D model? This is because RISA-3D cannot build the stiffness matrix with the configuration you have modeled.

When running a truss model in RISA-3D, it’s quite common to receive an instability warning, but these can be easily resolved by following a few simple rules.

When your RISA-3D model is not behaving as you anticipated, one of the best tools you have is viewing the deflected shape.

In RISA-3D, you can set a member to be tension-only by double-clicking on it and selecting Tension Only or Euler Buckling from the Advanced Member Properties.

There are several tips to modeling X-Bracing within RISA-3D that can help the model solve faster and give you better results.