This is the discussion forum for Helix Toolkit.
For bugs and new features, use the issue tracker located at GitHub.
Also try the chat room!

Texture coordinates from ObjReader

Anonymous 10 years ago updated by Kong Lee 2 years ago 15
This discussion was imported from CodePlex

Lolligeir wrote at 2013-03-22 18:08:

Hey! Thanks for an awesome tool.

I am reading some obj files for a ray tracer and I have managed to read the Points of each triangle and the normals but the texture coordinate don´t seem to be working correctly. This is how I am reading the file:
            ObjReader r = new ObjReader();
            Model3DGroup model = r.Read(modelUrl);
            GeometryModel3D gm1 = (GeometryModel3D)model.Children[0];
            MeshGeometry3D mg1 = (MeshGeometry3D)gm1.Geometry;
            Vector3DCollection normals = mg1.Normals;     
            System.Windows.Media.PointCollection textureCoordinates = mg1.TextureCoordinates;
            System.Windows.Media.Int32Collection indices = mg1.TriangleIndices;
            Point3DCollection points = mg1.Positions;

            for (int index = 0; index < indices.Count; index += 3)
                Point3D p0 = points[indices[index]];
                Point3D p1 = points[indices[index + 1]];
                Point3D p2 = points[indices[index + 2]];          
                Vector3D n0 = normals[indices[index]];
                Vector3D n1 = normals[indices[index + 1]];
                Vector3D n2 = normals[indices[index + 2]];

                System.Windows.Point t0 = textureCoordinates[indices[index]];
                System.Windows.Point t1 = textureCoordinates[indices[index + 1]];
                System.Windows.Point t2 = textureCoordinates[indices[index + 2]];
This loads the correct points and normals but the texture coordinates come out wrong. Am I approacing this incorrectly? How do you read the correct texture coordinate for every face?

The obj file I have been using (Removed text after vertices to get the objReader to read it) :

Best regards,

How to access different component from .3ds file

Anonymous 10 years ago 0
This discussion was imported from CodePlex

GhufranZahidi wrote at 2012-11-20 10:04:


I want to access multiple component from .3ds file by name and try to move particular component, is it possible if yes then give method name, please reply

Under review

HelixVisual3d not updating after created

Rodrigo Basniak 10 years ago updated by Kong Lee 2 years ago 212

I'm need to show a circular torus on the viewport. The closest option I found was the HelixVisual3D, but it has open ends. So I tried to create my own class to draw this, with a HelixVisual3D and two thin cones to close the ends. I used the classes from the Building Demo as reference, so I came up with this:

public class TorusVisual3D : UIElement3D
    public static readonly DependencyProperty AngleProperty = DependencyPropertyEx.Register("Angle", 90, (s, e) => s.AppearanceChanged());
    public static readonly DependencyProperty RadiusProperty = DependencyPropertyEx.Register("Radius", 0.35, (s, e) => s.AppearanceChanged());
    public static readonly DependencyProperty DiameterProperty = DependencyPropertyEx.Register("Diameter", 0.1, (s, e) => s.AppearanceChanged());

    private GeometryModel3D torus = new GeometryModel3D();
    private GeometryModel3D cap1 = new GeometryModel3D();
    private GeometryModel3D cap2 = new GeometryModel3D();

    public TorusVisual3D()

        Model3DGroup model = new Model3DGroup();


        this.Visual3DModel = model;

    public double Angle
            return (double)this.GetValue(AngleProperty);
           this.SetValue(AngleProperty, value);

    public double Radius
            return (double)this.GetValue(RadiusProperty);
            this.SetValue(RadiusProperty, value);

    public double Diameter
            return (double)this.GetValue(DiameterProperty);
            this.SetValue(DiameterProperty, value);

    private void AppearanceChanged()
        Material mat = MaterialHelper.CreateMaterial(Utils.GetRandomColor());

        HelixVisual3D h = new HelixVisual3D();
        h.Origin = new Point3D(0, 0, 0);
        h.Diameter = Diameter;
        h.Turns = Angle / 360.0;
        h.Radius = Radius;
        h.Length = 0;
        h.BackMaterial = mat;
        h.Material = mat;
        this.torus = h.Model;

        MeshBuilder cap1Builder = new MeshBuilder(false, false);
        Point3D p1 = new Point3D(0, Radius, 0);
        cap1Builder.AddCone(p1, new Vector3D(0, 1, 0), h.Diameter / 2, h.Diameter / 2, 0.0001, true, true, 40);
        this.cap1.Material = MaterialHelper.CreateMaterial(Colors.Yellow);
        this.cap1.Geometry = cap1Builder.ToMesh();

        MeshBuilder cap2Builder = new MeshBuilder(false, false);
        Point3D p2 = new Point3D(-1, 0, 0);
        cap2Builder.AddCone(p2, new Vector3D(1, 0, 0), h.Diameter / 2, h.Diameter / 2, 0.0001, true, true, 40);
        this.cap2.Material = MaterialHelper.CreateMaterial(Colors.Red);
        this.cap2.Geometry = cap2Builder.ToMesh();

To draw it I'm using the following code: 

    TorusVisual3D t = new TorusVisual3D();
    t.Angle = m_angle;
    t.Radius = m_radius1;
    t.Diameter = m_radius2 * 2.0;
    t.Transform = new TranslateTransform3D(0, 0, 0);
    ModelVisual3D model = new ModelVisual3D();
    var container = new ContainerUIElement3D();

The problem is that the Helix is drawn with the default values (Radius=0.35, Diameter=0.1 and Angle=90) and is never updated again. No matter what values I set on the Properties, it stays the same. The both cylinder are updated correctly, just the Helix isn't.

What am I'm doing wrong?

Thanks in advance,

Storyboard animation

Anonymous 10 years ago 0
This discussion was imported from CodePlex

xyxa wrote at 2012-07-14 15:56:

Thanks so much for very useful toolkit.

But unfortunately I could not create a storyboard animation via Blend for any MeshElement3D. It's strange, because I can create such animation for ModelVisual3D. What is the reason for this behavior and Is there any ways to solve it?


MeshGeometryHelper Cut Method

Anonymous 10 years ago 0
This discussion was imported from CodePlex

badgerbadger wrote at 2012-07-26 16:50:

I would like to modify the MeshGeometryHelper.Cut method so that it (also) meshes the opening created by the planar cut (i.e. currently the mesh is open at the location of the plane, I need a closed surface)

Can anyone figure out a neat way of achieving this in the Cut method? (Objo? :) )  (maybe uncommenting some of the commented-code in the Cut method achieves this..?)

Otherwise I guess I will have to get a contour of the planar mesh, attempt to mesh that surface and add to the Cut mesh - but a bit messy.

objo wrote at 2012-08-09 00:59:

Yes, you could change the cut method to also provide the contour(s). See the GetContourSegments...

When you have the contour(s), you can use the MeshBuilder.AddPolygonByCuttingEars to triangulate by the cutting/ears method (easy algorithm, but not very efficient).

badgerbadger wrote at 2012-08-09 10:41:

Many thanks Objo, yes I ended up doing something similar but used the AddPolygon instead of CuttingEars version (which I'll now investigate). I meant to post my hack but moved on to the next problem. Here is the mk1 code ( meshOrig is the original mesh while cutMesh is after the plane cut has been applied; plane is the cut plane).

I should add my code was not required to produce a nice mesh, it is only an intermediate step towards a bigger problem involving segmenting a mesh, so if others use it, it is worth investigating replacing AddPolygon (which applies a fan mesh)..

        private static MeshGeometry3D MeshPlaneCut(MeshGeometry3D meshCut, MeshGeometry3D meshOrig, Plane3D plane)
            //Store the positions on the cut plane
            var segments = MeshGeometryHelper.GetContourSegments(meshOrig, plane.Position, plane.Normal).ToList();

            //assumes largest contour is the outer contour!
            IList<Point3D> vertexPoints = MeshGeometryHelper.CombineSegments(segments, 1e-6).ToList().OrderByDescending(x=>x.Count).First();

            //meshCut the polygon opening and add to existing cut mesh
            var builder = new MeshBuilder(false,false);
            builder.Append(meshCut.Positions, meshCut.TriangleIndices);
            MeshGeometry3D mg3D = builder.ToMesh();

            return mg3D;

ulissespi wrote at 2012-12-24 08:06:

I'm also interested in having a MeshGeometryHelper.Cut that as result creates a solid (non hollow) mesh.

I changed the ApplyCuttingPlanesToModel method in the CuttingPlaneGroup.cs file, replacing the call   

g = MeshGeometryHelper.Cut(g, p, n);


g = MeshGeometryHelper.MeshPlaneCut(g, p, n);   

to use the method described in the previous post, but obviously it didn't work as the parameters are not the same.

Could you please give a bit more detail on how do you call your new method?

(maybe have a piece of the calling code) 


Or if someone else found another way of resolving this issue, other code examplesare wellcome.

badgerbadger wrote at 2012-12-24 11:39:

Hi Ulissepi - I should point out that my problem wasn't concerned with drawing a cut (and closed) mesh, only in calculating the mesh so that I could apply a contour algorithm to it. If you need to display the visual then something more sophisticated will be required.

I've tried to pick out the relevant bits from my code. It's been a while so hopefully I have included everything relevant. Hope it helps!

Geometry3D originalGeometry = model.Geometry;
//create a copy of the mesh
var g = originalGeometry as MeshGeometry3D;
MeshGeometry3D gOrig = g.Clone();

//Cut the Mesh and then apply the cutplane

//cp, p & n are the cut plane (Plane3D) and the position (Point3D) and the normal (Vector3D) of the plane

g = MeshGeometryHelper.Cut(g, p, n);

g = MeshPlaneCut(g, gOrig, cp);

GeometryModel3D gm3d = model.Clone();
 gm3d.Geometry = g;


Collision Detection

Anonymous 10 years ago updated by anonymous 7 years ago 3
This discussion was imported from CodePlex

BCBlanka wrote at 2012-11-10 08:47:



Is there a way to detect collision between 3D models?




objo wrote at 2012-11-11 22:14:

sorry, no collision detection is implemented in this library. But it would be interesting to see integration of the models defined here with bullet or some other physics library! 

bcblanka wrote at 2012-11-12 06:40:

Thanks for the prompt response.



davidop wrote at 2013-05-28 16:53:

Did you find the solution? What library do you recommend? Do you have any example?

BCBlanka wrote at 2013-05-29 10:10:

I ended up comparing the bounds of the models (Rect3D) and checking their intersection. This was enough for what I needed.

davidop wrote at 2013-05-30 11:00:

Do not you will have a small example? I need it for when moving objects (ModelVisual3D) with the mouse

objo wrote at 2013-06-07 12:01:

A small collision detection demo is on the wish list! Simple geometries (boxes) would be sufficient. Also a larger demo combining WPF3D and one of the well-known physics engines would be very interesting to see. Sorry, I don't have time to do this myself at the moment :)

manipulator scale problem ?

Anonymous 10 years ago 0
This discussion was imported from CodePlex

Mrme wrote at 2013-07-19 13:50:

I added a .obj model and attached a combinedManipulator to it, the combined manipulator works fine but it is super small, so I scaled it using ScaleTransform3D, but then the translation became super slow, my mouse gets to the end of the screen and the model moves only really small motion. the rotation works fine though, I wonder how can I scale it correctly to have it full functioning.


Mrme wrote at 2013-07-24 17:15:

Hi again, the problem is : in real life we use more sophisticated 3D models than just a the manipulator example the CombinedManipulator just fits the cube and work nicely, there is no special code there just two lines of code in the XAML to create and hook the model to the manipulator, in my 3D model the CombinedManipulator comes really really small , some times you can't even see it without zooming , after zooming it works mostly fine, scaling anyone of them to match the other just brings more problems with the manipulator, whether the translation will be useless or some times the manipulator gets detached from the model and move separately. here is my .obj model , I would appreciate it if someone can successfully attach CombinedManipulator to it.

Thanks in advance

Mrme wrote at 2013-08-02 10:41:

I solved it , basically I edited the library code, I bound 10% and the full value of the diameter property of the CombinedManipulator to the diameter property and the length property of the TranslationManipulator respectively, when I bind the diameter of my CombinedManipulator to the X or Y values of a BoundingBox for my model , I have a reasonable looking , fully functioning manipulator, may be objo will be interested in submitting these changes.

How to change the view to a standard-view in code?

Mehdi Rafeie 8 years ago updated by fresh 9 months ago 6

Hello there,

Thank you for your nice toolkit. I would like to know how to change the camera view to a standard view, such as top view, in code? Simply, I need a piece of code to do exactly what is happening by clicking on a side of the ViewCube.


Zoom out

Anonymous 10 years ago 0
This discussion was imported from CodePlex

Cygor6 wrote at 2012-11-23 22:40:

I'm beginners and would need your help! I made a console application 
to save down a rendered image. BUT the camera is too close and
I can not somehow zoom out.

How do I solve this?
using System.IO;
using System.Threading;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Media3D;
using System.Windows.Shapes;
using HelixToolkit.Wpf;

namespace ConsoleApplication1
    internal class Program
        public static IHelixViewport3D HelixView { get; set; }
        public static Model3D MyModel { get; set; }

        private static void Main(string[] args)
            var thread = new Thread(Test);

        private static void Test()
            var c = new FileStream("Ferarri40.3ds", FileMode.Open, FileAccess.Read, FileShare.Read);
            var reader = new StudioReader {TexturePath = "."};
            MyModel = reader.Read(c);

            var m = new ModelVisual3D {Content = MyModel};

            const string Path = @"H:\test.png";
            const int Height = 480;
            const int Width = 640;

            var vp = new HelixViewport3D {Width = Width, Height = Height};


            vp.Children.Add(new DefaultLights());

            var zoom = new ScaleTransform3D(1.5, 1.5, 1.5);
            var t = new Transform3DGroup();
            vp.Camera.Transform = t;

            vp.Camera = CameraHelper.CreateDefaultCamera();
            vp.Camera.Position = new Point3D(5.300, -12.300, 3.300);
            vp.Camera.LookDirection = new Vector3D(-6.300, 11.000, -6.600);
            vp.Camera.UpDirection = new Vector3D(0.000, 0.000, 1.000);
            vp.Camera.NearPlaneDistance = 0.123;         

            var r = new Rectangle {Width = vp.ActualWidth, Height = vp.ActualHeight};
            var cb = new BitmapCacheBrush(vp) {BitmapCache = new BitmapCache(0)};
            r.Fill = cb;
            r.Arrange(new Rect(0, 0, r.Width, r.Height));


Position of imported model

Anonymous 10 years ago 0
This discussion was imported from CodePlex

afra89 wrote at 2011-12-21 10:04:

I have successfully imported an model and i can easily rotate it via the Transform property. But how can i set the position of the model? There is no .Center property like the Sphere and Cube..