Command.cs

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// Written by Autodesk Platform Services
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using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;

using Newtonsoft.Json;

using Autodesk.Max;

namespace Autodesk.Forge.Sample.DesignAutomation.Max
{
    /// <summary>
    /// Used to hold the parameters to change
    /// </summary>
    public class InputParams
    {
        public float Width { get; set; }
        public float Height { get; set; }
    }
    /// <summary>
    /// Changes parameters in automated way. 
    /// Iterate entire scene to get all nodes
    /// In this example we specifically find Casement Windows by object class ID
    /// Then modify the width and height based on inputs.
    /// 
    /// Could be expanded to find other window types, other objects, etc.
    /// </summary>
    static public class ParameterChanger
    {
        static List<IINode> m_sceneNodes = new List<IINode> { };

        /// <summary>
        /// Recursively go through the scene and get all nodes
        /// Use the Autodesk.Max APIs to get the children nodes
        /// </summary>
        static private void GetSceneNodes(IINode node)
        {
            m_sceneNodes.Add(node);

            for (int i = 0; i < node.NumberOfChildren; i++)
                GetSceneNodes(node.GetChildNode(i));
        }

        /// <summary>
        /// Function to specifically update Case Windows with input wedth and height parameters
        /// </summary>
        /// <param name="width">The new Width to set the Window</param>
        /// <param name="height">The new Height to set the Window</param>
        /// <returns>window count</returns>
        static public int UpdateWindowNodes(float width, float height)
        {
            IGlobal globalInterface = Autodesk.Max.GlobalInterface.Instance;
            IInterface14 coreInterface = globalInterface.COREInterface14;

            IINode nodeRoot = coreInterface.RootNode;
            m_sceneNodes.Clear();
            GetSceneNodes(nodeRoot);

            // 3ds Max uses a class ID for all object types. This is easiest way to find specific type.
            // ClassID (1902665597L, 1593788199L) == 0x71685F7D, 0x5EFF4727 for casement window
            IClass_ID cidCasementWindow = globalInterface.Class_ID.Create(0x71685F7D, 0x5EFF4727);

            // Use LINQ to filter for windows only - in case scene has more than one, 
            // but this should still give us at least one for single window scene!
            var sceneWindows = from node in m_sceneNodes
                               where ((node.ObjectRef != null) && // In some cases the ObjectRef can be null for certain node types.
                                      (node.ObjectRef.ClassID.PartA == cidCasementWindow.PartA) && 
                                      (node.ObjectRef.ClassID.PartB == cidCasementWindow.PartB))
                               select node;

            // Iterate the casement windws and update the hight and width parameters.
            foreach (IINode item in sceneWindows)
            {
                // window is using old-style ParamArray rather than newer ParamBlk2
                IIParamArray pb = item.ObjectRef.ParamBlock;
                pb.SetValue(0, coreInterface.Time, height); // window height is at index zero.
                pb.SetValue(1, coreInterface.Time, width); // window width is at index one.
            }

            // If there are windows, save the window updates
            int status;
            if (sceneWindows.Count() > 0)
            {
                // The output file name must match what the Design Automation work item is specifying as output file.
                string full_filename = coreInterface.CurFilePath;
                string filename = coreInterface.CurFileName;
                string new_filename = full_filename.Replace(filename, "outputFile.max");
                status = coreInterface.SaveToFile(new_filename, true, false);
                if (status == 0) //error
                    return -1;
            }

            // return how many windows were modified.
            return sceneWindows.Count();
        }

    }

    /// <summary>
    /// This class is used to execute the automation. Above class could be connected to UI elements, or run by scripts directly.
    /// This class takes the input from JSON input and uses those values. This way it is more cohesive to web development.
    /// </summary>
    static public class RuntimeExecute
    {
        static public int ModifyWindowWidthHeight()
        {
            int count = 0;

            // Run entire code block with try/catch to help determine errors
            try
            {
                // read input parameters from JSON file
                InputParams inputParams = JsonConvert.DeserializeObject<InputParams>(File.ReadAllText("params.json"));
                count = ParameterChanger.UpdateWindowNodes(inputParams.Width, inputParams.Height);
            }
            catch (Exception e)
            {
                LogTrace("Exception Error: " + e.Message);
                return -1; //fail
            }
            LogTrace("Changed {0} window objects.", count);
            return count; // 0+ means success, and how many objects were changed.
        }
        /// <summary>
        /// Information sent to this LogTrace will appear on the Design Automation output
        /// </summary>
        private static void LogTrace(string format, params object[] args)
        {
            IGlobal globalInterface = Autodesk.Max.GlobalInterface.Instance;
            IInterface14 coreInterface = globalInterface.COREInterface14;
            ILogSys log = coreInterface.Log;
            // Note flags are necessary to produce Design Automation output. This is same as C++:
            // SYSLOG_INFO | SYSLOG_IGNORE_VERBOSITY | SYSLOG_BROADCAST
            log.LogEntry(0x00000004 | 0x00040000 | 0x00010000, false, "", string.Format(format, args));
        }
    }
}