grasshopper-component

Grasshopper Component Development

Component Class Template

using System;
using System.Collections.Generic;
using Grasshopper.Kernel;
using Grasshopper.Kernel.Types;
using Rhino.Geometry;

namespace MyGHPlugin
{
    public class MyComponent : GH_Component
    {
        // Constructor: (name, nickname, description, category, subcategory)
        public MyComponent()
            : base("My Component", "MyCmp",
                   "Description of what this component does",
                   "MyPlugin", "Operations")
        { }

        // Unique GUID — generate once and never change
        public override Guid ComponentGuid => new Guid("PUT-YOUR-GUID-HERE");

        // Optional: 24x24 icon
        protected override System.Drawing.Bitmap Icon => null;

        // Optional: component exposure in the ribbon
        public override GH_Exposure Exposure => GH_Exposure.primary;

        protected override void RegisterInputParams(GH_InputParamManager pManager)
        {
            // Add inputs (index order matters — matches DA.GetData calls)
            pManager.AddPointParameter("Point", "P", "Input point", GH_ParamAccess.item);
            pManager.AddNumberParameter("Distance", "D", "Distance value", GH_ParamAccess.item, 1.0); // default value
            pManager.AddCurveParameter("Curves", "C", "Input curves", GH_ParamAccess.list);
            pManager.AddBrepParameter("Brep", "B", "Input brep", GH_ParamAccess.item);
            pManager.AddGenericParameter("Any", "A", "Any type", GH_ParamAccess.item);
            
            // Make a parameter optional
            pManager[1].Optional = true;
        }

        protected override void RegisterOutputParams(GH_OutputParamManager pManager)
        {
            pManager.AddPointParameter("Result", "R", "Output point", GH_ParamAccess.item);
            pManager.AddCurveParameter("Curves", "C", "Output curves", GH_ParamAccess.list);
            pManager.AddNumberParameter("Values", "V", "Computed values", GH_ParamAccess.tree);
        }

        protected override void SolveInstance(IGH_DataAccess DA)
        {
            // 1. Collect inputs
            Point3d point = Point3d.Unset;
            if (!DA.GetData(0, ref point)) return; // required — abort if missing
            
            double distance = 1.0;
            DA.GetData(1, ref distance); // optional — don't abort on failure

            List<Curve> curves = new List<Curve>();
            if (!DA.GetDataList(2, curves)) return;

            Brep brep = null;
            DA.GetData(3, ref brep);

            // 2. Validate
            if (point == Point3d.Unset)
            {
                AddRuntimeMessage(GH_RuntimeMessageLevel.Error, "Invalid point.");
                return;
            }
            if (distance <= 0)
            {
                AddRuntimeMessage(GH_RuntimeMessageLevel.Warning, "Distance should be positive.");
                distance = Math.Abs(distance);
            }

            // 3. Compute
            Point3d result = point + new Vector3d(distance, 0, 0);

            // 4. Set outputs
            DA.SetData(0, result);
            DA.SetDataList(1, curves);
            // DA.SetDataTree(2, someTree); -- see DataTree section
        }
    }
}