How to zoom to a model in a helix-toolkit sharpdx viewport?

Question

Following setup: I have an application with two viewports. When choosing an element on the main viewport, a copy of the model geometry is supposed to be displayed enlarged in the second viewport.

I uploaded a screenshot for some visual aid :-) http://imgur.com/ILG8Ylk

My take on this (among others) is to use the ZoomExtents method:

MainViewModel.cs

    public void SetDetailedModelGeometry(MeshGeometryModel3D geometry)
    {

        MyDetailedModel = new Element3DCollection();
        MyModelViewportDetailed.Reset();

        if (geometry != null)
        {
            var bounds = geometry.Bounds;

            //var rec = new Rect3D(bounds.Minimum.X, bounds.Minimum.Y, bounds.Minimum.Z, bounds.Maximum.X,bounds.Maximum.Y,bounds.Maximum.Z);

            this.MyDetailedModel.Add(geometry);
            MyDetailedModel[0].Attach(MyModelViewportDetailed.RenderHost);

            this.OnPropertyChanged("MyDetailedModel");

            MyModelViewportDetailed.ZoomExtents();
            //MyModelViewportDetailed.ZoomExtents(rec);

        }

    }

I guess both overloads should fit the scene nicely to the bound model, but I always end up with a very zoomed out view and most of the models are not centered in the viewport.

I tried to hack a solution by translating the model into the origin and by applying a zoom-force, the result is better but still kind of meh.

    public void SetDetailedModelGeometry(MeshGeometryModel3D geometry)
    {

        MyDetailedModel = new Element3DCollection();
        MyModelViewportDetailed.Reset();

        if (geometry != null)
        {

            var bounds = geometry.Bounds;
            var rec = new Rect3D( bounds.Minimum.X, bounds.Minimum.Y, bounds.Minimum.Z,  bounds.Maximum.X, bounds.Maximum.Y, bounds.Maximum.Z);
            // move model 

            var delta = new Point3D(Math.Abs(bounds.Maximum.X - bounds.Minimum.X), Math.Abs(bounds.Maximum.Y - bounds.Minimum.Y), Math.Abs(bounds.Maximum.Z - bounds.Minimum.Z));
            var center = new Point3D(bounds.Minimum.X+delta.X, bounds.Minimum.Y+delta.Y, bounds.Minimum.Z+delta.Z);

            TransformDetailed = new TranslateTransform3D(-center.X,-center.Y,-center.Z);
            geometry.Transform = TransformDetailed;

            // notice property change
            this.MyDetailedModel.Add(geometry);
            MyDetailedModel[0].Attach(MyModelViewportDetailed.RenderHost);

            this.OnPropertyChanged("MyDetailedModel");

            MyModelViewportDetailed.ZoomExtents();
            MyModelViewportDetailed.CameraController.AddZoomForce(-1.0);


        }

Does somebody have a clue why the zoomExtends() method is not working for me? And if not, maybe has suggestions for a more sophisticated hack xD.

I'm quite the junior developer, so I'm open for any comments for improvements, thanks.

Answer 1

You could try a few things. First make sure IsZoomEnabled and ZoomExtentsWhenLoaded on your viewport are set to true. You can calculate the Bounds by yourselft, for alot off MeshModels this would be a bootleneck but for just on Geometry it will be sufficient.

            var mx= (this.ModelGeometry[0] as MeshGeometryModel3D).Geometry.Positions.Min(item => item.X);
            var my = (this.ModelGeometry[0] as MeshGeometryModel3D).Geometry.Positions.Min(item => item.Y);
            var mz = (this.ModelGeometry[0] as MeshGeometryModel3D).Geometry.Positions.Min(item => item.Z);
            BoundingBox bounds = new BoundingBox(new Vector3(mx, my, mz), new Vector3(x, y, z));

Another hint, I had a small timing problem in my application, I was loading and attaching step files with 10000++ MeshModels and before calling ZoomExtends I had to wait some 100 ms. You could do this via a timer or task delay.

I see you are using the PerspectiveCamera. Via OrthotraphicCamera you could set the Zoom yourself by setting the width property of the camera.