However, "Gnacad" is not a widely recognized standard software name in major academic repositories. It is most likely you are referring to GNA (Generic Network Analyzer/Architecture) used in control systems or networking research.
: Use "Add select object" for closed shapes like circles and rectangles. For complex or overlapping areas, use "Add Pick points". Interface Navigation gnacad tutorial pdf
Do not despair. Here is a practical roadmap to getting the information you need, formatted as a PDF if necessary. However, "Gnacad" is not a widely recognized standard
This paper outlines the prerequisites for performing GNA, the mathematical notation used, and a practical workflow for analysis. This paper outlines the prerequisites for performing GNA,
Downloading and Installing GnuCash