Add move-copy body feature with coincident mate using SOLIDWORKS API

Move-Copy Body Property Manager Page with mates added

C# VSTA macro example which finds the largest planar face of the selected body and inserts move-copy body feature in part and adds coincident mate with Front Plane using SOLIDWORKS API.

Open part document
Select any body which contains the planar face
Run the macro. As the result move-copy body feature is inserted via IFeatureManager::InsertMoveCopyBody2 SOLIDWORKS API method. Then coincident mate is added between the largest face of the body and front plane using IMoveCopyBodyFeatureData::AddMate SOLIDWORKS API method.

using SolidWorks.Interop.sldworks;
using SolidWorks.Interop.swconst;
using System;
using System.Linq;
using System.Runtime.InteropServices;

namespace MoveBodyMate
{
    public partial class SolidWorksMacro
    {
        public void Main()
        {
            try
            {
                var model = swApp.IActiveDoc2;
                var body = model.ISelectionManager.GetSelectedObject6(1, -1) as IBody2;

                if (body == null)
                {
                    throw new NullReferenceException("Select body to move");
                }

                var plane = FindFrontPlane(model);
                var face = FindLargestPlanarFace(body);

                AddCoincidentMate(model, body, plane as IEntity, face as IEntity);
            }
            catch(Exception ex)
            {
                swApp.SendMsgToUser2(ex.Message, (int)swMessageBoxIcon_e.swMbStop, (int)swMessageBoxBtn_e.swMbOk);
            }
        }

        private static void AddCoincidentMate(ModelDoc2 model, IBody2 body, IEntity mateEnt, IEntity mateEntOnBody)
        {
            var selData = model.ISelectionManager.CreateSelectData();
            selData.Mark = 1;

            if (!body.Select2(false, selData))
            {
                throw new InvalidOperationException("Failed to select body");
            }

            var moveCopyBodyFeat = model.FeatureManager.InsertMoveCopyBody2(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, false, 1);

            var featData = moveCopyBodyFeat.GetDefinition() as IMoveCopyBodyFeatureData;

            if (featData.AccessSelections(model, null))
            {
                int err;

                var mate = featData.AddMate(new DispatchWrapper[]
                {
                    new DispatchWrapper(mateEnt),
                    new DispatchWrapper(mateEntOnBody)
                }, (int)swMateType_e.swMateCOINCIDENT, (int)swMateAlign_e.swMateAlignCLOSEST, 0, 0, out err);

                if (mate == null)
                {
                    throw new NullReferenceException(string.Format("Failed to add mate: {0}", (swAddMateError_e)err));
                }

                if (!moveCopyBodyFeat.ModifyDefinition(featData, model, null))
                {
                    throw new InvalidOperationException("Failed to apply feature changes");
                }
            }
            else
            {
                throw new InvalidOperationException("Failed to access the definition");
            }
        }

        private IFeature FindFrontPlane(IModelDoc2 model)
        {
            var feat = model.IFirstFeature();

            while (feat != null && feat.GetTypeName2() != "RefPlane")
            {
                feat = feat.IGetNextFeature();
            }

            if (feat == null)
            {
                throw new NullReferenceException("Failed to find the front plane");
            }

            return feat;
        }

        private IFace2 FindLargestPlanarFace(IBody2 body)
        {
            var faces = body.GetFaces() as object[];

            if (faces == null)
            {
                throw new NullReferenceException("Body doesn't contain faces");
            }

            var face = faces.Cast<IFace2>()
                .Where(f => f.IGetSurface().IsPlane())
                .OrderBy(f => f.GetArea()).LastOrDefault();

            if (face == null)
            {
                throw new NullReferenceException("There are no planar faces in this body");
            }

            return face;
        }

        public SldWorks swApp;
    }
}