Creating Section of Solid in Drawing

I could not get section of Truss (solid) by using following code.

        private void Truss2DDrawingKalip_Shown(object sender, EventArgs e)
        {

            var sheet = new devDept.Eyeshot.Sheet(devDept.Geometry.linearUnitsType.Centimeters, 42, 29.7, "Truss Elevation", 0);

            kalipDrawing.Sheets.Clear();             // Remove old sheets (optional but safe)
            kalipDrawing.Sheets.Add(sheet);          // Add your new sheet
            kalipDrawing.ActiveSheet = sheet;        // Make it visible
            kalipDrawing.Invalidate();               // Force redraw to update UI

            var fullDesign = designKalipDoc; // your original full model
            fullDesign.Entities.Regen();

            // Compute the bounding box of the model
            var bboxMax = designKalipDoc.Entities.BoxMax;
            var bboxMin = designKalipDoc.Entities.BoxMin;
            double centerX = sheet.Width / 2;
            double centerY = sheet.Height / 2;

            // Get corners properly
            Point3D minPt = new Point3D(bboxMin.X, 0, bboxMin.Z);
            Point3D maxPt = new Point3D(bboxMax.X, 0, bboxMax.Z);

            // Compute width and height
            double modelWidth = maxPt.X - minPt.X;
            double modelHeight = maxPt.Z - minPt.Z;

            double scaleX = sheet.Width / modelWidth * 0.8;   // 80% of sheet
            double scaleY = sheet.Height / modelHeight * 0.8; // 80% of sheet
            double scale = Math.Min(scaleX, scaleY);

            // Create a centered VectorView
            var frontView = new VectorView(centerX, centerY, devDept.Eyeshot.viewType.Front, scale / 100, "Front View");

            //sheet.Entities.Add(frontView); // <-- make sure this is added to sheet.Views before using it as parent
            //designKalipDoc.Viewports.Add(new Viewport());
            sheet.AddViewPlaceHolder(frontView, fullDesign, kalipDrawing, "Front View");

            designKalipDoc.Entities.Regen();

            // Finally rebuild
            kalipDrawing.Rebuild(designKalipDoc, false, false);

            double midX = (bboxMin.X + bboxMax.X) / 2.0;
            double depth = 2.0; // depth in cm

            // 2. Compute box size (YZ span)
            double width = bboxMax.Y - bboxMin.Y;
            double height = bboxMax.Z - bboxMin.Z;

            // 3. Create a solid clipping box at midX
            Solid clippingBox = Solid.CreateBox(depth, width, height); // Box along X
            clippingBox.Translate(midX - depth / 2, bboxMin.Y, bboxMin.Z);

            // 4. Intersect all solids in the model with the clipping box
            Design clippedDesign = new Design();

            foreach (Entity ent in designKalipDoc.Entities)
            {
                if (ent is Solid solid)
                {
                    var copy = solid.Clone() as Solid;
                    if (copy == null)
                        continue;

                    Solid[] result = Solid.Intersection(copy, clippingBox);
                    if (result != null && result.Length > 0)
                        clippedDesign.Entities.AddRange(result);
                }
            }

            clippedDesign.Entities.Regen();

            // Define a section line that cuts vertically at the midpoint
            double viewWidth = modelWidth * scale;
            double viewHeight = modelHeight * scale;

            // Section line placed at the vertical mid-span
            double sectionX = viewWidth / 2;
            Point2D sectionLineP0 = new Point2D(sectionX, 0);           // bottom of view
            Point2D sectionLineP1 = new Point2D(sectionX, viewHeight);  // top of view

            // Place SectionView under the FrontView
            Point2D sectionViewPosition = new Point2D(centerX, centerY - viewHeight - 5);

            // Define the SectionView correctly using parent View
            SectionView sectionView = new SectionView(
                sectionViewPosition,
                frontView,
                sectionLineP0,
                sectionLineP1,
                "Section A-A"
            );

            clippedDesign.Viewports.Add(new Viewport());

            //sheet.Entities.Add(sectionView);
            sheet.AddViewPlaceHolder(sectionView, clippedDesign, kalipDrawing, "Section A-A");
            kalipDrawing.Rebuild(clippedDesign, false, false);

            AddTrussDimension(sheet, scale, modelWidth, modelHeight);

        }