ClippingPlane (Eyeshot) mesh not visible

Question

I am struggling to show meshed planes when executing Edit() function from ClippingPlane1 from my Model. It only shows the moving reference coordinate, cappings, objects, etc... except the planes. When debugging, it appears that the clippingPlaneMesh (internal structure) has been actually computed but with Visible = false. I tried with ProcessClippingPlanesVisibility(gcnew cli::array<ClippingPlane^>(1) { Model1->ClippingPlane1 }, true) function but without success. I had also made sure that ShowPlane is true.

Do you know how to show the plane mesh of the clipping Plane?

Thanks

Abdoulaye

Answer 1

I created a minimally reproduceable model of the clipping plane. From DevDept's Volumetric Rendering Example. Two things I noticed are that you need to ensure the viewport is redrawn (viewport.Invalidate(); ) after the Edit(null) is called. Also in the example Plane.Origin.Z is messed with. Somehow this does not get re-rendered unless the full plane of the clippingPlane1 is changed:

viewportLayout1.ClippingPlane1.Plane = new Plane(new Point3D(7, 7, 7), new Vector3D(0, 0, 1));

Code for ClippingPlane1:

private void addClippingPlane()
{
    // Remove Clipping Plane if Active
    if (viewportLayout1.ClippingPlane1.Active) { viewportLayout1.ClippingPlane1.Cancel(); }

    //sets the Z coordinate of the origin of the clippingPlane      
    viewportLayout1.ClippingPlane1.Plane = new Plane(new Point3D(7, 7, 7), new Vector3D(0, 0, 1));
            
    // enables a clippingPlane                           
    viewportLayout1.ClippingPlane1.Edit(null);          
            
    // refresh the viewport
    viewportLayout1.Invalidate();
}

Another method to clip meshes is CutBy. This method allows meshes to be cut individually by a plane. Unfortunately plane is a Geometry child vice and Entity Child, so it cannot be added to the viewport as a plane. To alleviate this, it can be drawn using the Quad entity, with a length given for the drawn sides.

CutBy Example:

private void addCutByPlane()
{
    // Remove Clipping Plane if Active
    if (viewportLayout1.ClippingPlane1.Active) { viewportLayout1.ClippingPlane1.Cancel(); }

    //  Create Meshes
    Plane cutPlane1 = new Plane(new Point3D(7, 7, 7), new Vector3D(0, 0, 1));
    Mesh square = Mesh.CreateBox(15, 15, 15);

    // Cut Mesh by Plane
    square.CutBy(cutPlane1);

    // Length of Drawn part of plane
    double drawPlaneLength = 16;
    double hL = drawPlaneLength / 2;

            
    // Draw Plane region as a Quad Entity
    Point3D pO = cutPlane1.Origin;
    Point3D q1 = (pO + (cutPlane1.AxisX + cutPlane1.AxisY) * hL);
    Point3D q2 = (pO - (cutPlane1.AxisX - cutPlane1.AxisY) * hL);
    Point3D q3 = (pO - (cutPlane1.AxisX + cutPlane1.AxisY) * hL);
    Point3D q4 = (pO + (cutPlane1.AxisX - cutPlane1.AxisY) * hL);           

    Quad drawCutPlane1 = new Quad(q1, q2, q3, q4);
            
    viewportLayout1.Entities.Clear();
    viewportLayout1.Entities.Add(drawCutPlane1, Color.Red);
    viewportLayout1.Entities.Add(square, Color.Blue);

    viewportLayout1.Invalidate();
}

Full Example:

using System;
using System.Drawing;
using System.Windows.Forms;
using devDept.Eyeshot.Entities;
using devDept.Geometry;

namespace EyeshotTest
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            makeSquare();
        }

        private void makeSquare()
        {
            Mesh square = Mesh.CreateBox(15, 15, 15);
            viewportLayout1.Entities.Add(square, Color.Green);
            viewportLayout1.Invalidate();           
        }

        private void addClippingPlane()
        {
            // Remove Clipping Plane if Active
            if (viewportLayout1.ClippingPlane1.Active) { viewportLayout1.ClippingPlane1.Cancel(); }

            //sets the Z coordinate of the origin of the clippingPlane      
            viewportLayout1.ClippingPlane1.Plane = new Plane(new Point3D(7, 7, 7), new Vector3D(0, 0, 1));
            
            // enables a clippingPlane                           
            viewportLayout1.ClippingPlane1.Edit(null);          
            
            // refresh the viewport
            //viewportLayout1.Entities.Regen(); 
            // ^ unneeded, but when in doubt always Regen & Invalidate
            // Then remove them where ever possible for speed improvments
            viewportLayout1.Invalidate();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            addClippingPlane();
        }

        private void addCutByPlane()
        {
            // Remove Clipping Plane if Active
            if (viewportLayout1.ClippingPlane1.Active) { viewportLayout1.ClippingPlane1.Cancel(); }

            //  Create Meshes
            Plane cutPlane1 = new Plane(new Point3D(7, 7, 7), new Vector3D(0, 0, 1));
            Mesh square = Mesh.CreateBox(15, 15, 15);

            // Cut Mesh by Plane
            square.CutBy(cutPlane1);

            // Length of Drawn part of plane
            double drawPlaneLength = 16;
            double hL = drawPlaneLength / 2;

            
            // Draw Plane region as a Quad Entity
            Point3D pO = cutPlane1.Origin;
            Point3D q1 = (pO + (cutPlane1.AxisX + cutPlane1.AxisY) * hL);
            Point3D q2 = (pO - (cutPlane1.AxisX - cutPlane1.AxisY) * hL);
            Point3D q3 = (pO - (cutPlane1.AxisX + cutPlane1.AxisY) * hL);
            Point3D q4 = (pO + (cutPlane1.AxisX - cutPlane1.AxisY) * hL);           

            Quad drawCutPlane1 = new Quad(q1, q2, q3, q4);
            
            viewportLayout1.Entities.Clear();
            viewportLayout1.Entities.Add(drawCutPlane1, Color.Red);
            viewportLayout1.Entities.Add(square, Color.Blue);

            viewportLayout1.Invalidate();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            addCutByPlane();
        }
    }
}