Question
Why do boundary conditions sometimes get assigned incorrectly after changing model parameters in Grasshopper, and how can I fix it?
Answer
When you modify parameters like span length or center-to-center distance in your Grasshopper model, the “Get Node” component may still reference old or incorrect nodes from the previous geometry. This can lead to incorrect assignment of boundary conditions or loads.
This issue occurs because the “Get Node” component doesn’t automatically clear outdated data, and using “Clean and Recalculate” does not reset these components effectively.
To fix this, it is recommended to use a “Trigger” component connected to the input of the “Get Node” component. The Trigger forces a fresh recalculation, ensuring only the latest geometry and node data are used. This helps avoid persistent errors and improves control over data flow.
Before using Trigger:
After using Trigger:
Tip : Always use Trigger with components like “Get Node” that don’t auto-refresh, especially after geometry updates.