Alpaca4d

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Run your own OpenSees script ​

Run an OpenSees Tcl script of your own from Grasshopper, or add commands that Alpaca4d has no component for to a model built with it.

Custom Code wired between a model and Run Analysis on the Grasshopper canvas

Custom Code adds your lines to the model before Run Analysis.

You need ​

  • The Tcl lines, in a Panel or read from a .tcl file with Grasshopper's Read File.
  • Run Analysis, and the Grasshopper file saved.

Steps ​

A script of your own

  1. Place Custom Code and wire the lines into CustomCode. Leave AlpacaModel empty: the component starts an empty deck.
  2. Wire its AlpacaModel output into Run Analysis. Right-click Run Analysis, tick Do not use settings, and leave Settings empty. The script then runs as it stands, so it needs its own analyze and recorders.
  3. Run Analysis writes the deck into the AlpacaResults folder beside the Grasshopper file and runs OpenSees in the Grasshopper file's folder, so a recorder your script names without a folder writes there. Read it with Read File.

Commands added to an Alpaca4d model

  1. Wire the model from Assemble into AlpacaModel of Custom Code, and your lines into CustomCode.
  2. Wire Custom Code's AlpacaModel into Run Analysis, with Settings from Analysis Settings as usual. Your lines land after the model, before the recorder and the analysis that Run Analysis adds.
  3. Give anything you define a tag well above the ones in the deck: Custom Code's Tcl output shows the whole deck.

Check ​

  • Run Analysis's log has everything OpenSees printed. Analysis Failed: OpenSees exited with an error means a command failed, and the log names the line.
  • Custom Code's Tcl output shows where your lines landed.

Good to know ​

  • Nothing in your lines is checked. A mistake shows as an OpenSees error in the log, not as a red component.
  • With Do not use settings, the recorders from Assemble are not written into the script, and Run Analysis warns if there are any.
  • Custom Code does not show in Model View. To see an OpenSees model in Grasshopper, read its deck with Deserialise, which skips what Alpaca4d does not model.

See also ​