Sigma How to Define Tasks

Sigma Task Definition

Sigma can help guide users through tasks that are predefined in a .json file. The file is part of Sigma's persistent state, and is pointed to by the Sigma server configuration file under the <PersistentStateFilename> tag. For instance the following entry in the server configuration file:

<PersistentStateFilename>C:\psi\Applications\Sigma\Sigma\Resources\sigma.state.diamond</PersistentStateFilename>

specifies that the persistent state is saved at that location on disk. The tasks are specified in a file that has the same name and .tasklibrary.json appended to it. So, in the case above the task definition file is at C:\psi\Applications\Sigma\Sigma\Resources\sigma.state.diamond.tasklibrary.json. Here is a link to an existing sample task library file in the repo.

The first few lines of this file look like this:

{
  "Tasks": [
    {
      "Name": "Replace a hard-drive in a PC",
      "Steps": [
        {
          "$type": "Sigma.GatherStep, Sigma",
          "Label": "1",
          "Verb": "Gather",
          "Noun": "Objects",
          "Objects": [
            "hard-drive",
            "screwdriver"
          ]
        },
        {
          "$type": "Sigma.ComplexStep, Sigma",
          "Label": "2",
          "Description": "Open the PC case",
          "SubSteps": [
            {
              "$type": "Sigma.SubStep, Sigma",
              "Label": "1",
              "Description": "Unscrew the case screw using the screwdriver.",
              "VirtualObjects": [
                {
                  "Name": "Unscrew PC case",
                  "ModelType": "Half circle",
                  "SpatialPose": {
                    "$type": "Sigma.AtKnownSpatialLocation, Sigma",
                    "SpatialLocationName": "unscrew PC case"
                  }
                }
              ]
            },
            {
              "$type": "Sigma.SubStep, Sigma",
              "Label": "2",
              "Description": "Pull the handle and open and remove the case lid. Place the case lid on the table next to you.",
              "VirtualObjects": [
                {
                  "Name": "Open PC case",
                  "ModelType": "Quarter Circle",
                  "SpatialPose": {
                    "$type": "Sigma.AtKnownSpatialLocation, Sigma",
                    "SpatialLocationName": "Open PC case"
                  }
                }
              ]
            }
          ]
        },
        ...
    ...

The library consists of an array of tasks. Each task has a Name (in the example above "Replace a hard-drive in a PC"), and an array of steps. The $type parameter for each step specifies the type of the step. Sigma currently supports GatherStep, ComplexStep and DoStep step types.

A Gather step can specify a set of objects (or tools, ingredients, etc.) that the system will instruct the user to gather. A DoStep contains a simple description of an instruction to execute. The ComplexStep is a step that decomposes into a number of sub-steps.

The task library therefore contains a .json-serialized version of the corresponding data types in the code, see more in GatherStep.cs, ComplexStep.cs, DoStep.cs.