c# - Issues with making a 3D model faces semi-transparent using HelixToolkit

Question

I am trying to display the 3D model depicted below using HelixToolkit. (The following snapshot's taken from SolidWorks.)

I set the brush color of the DiffuseMaterial used as Material and BackMaterial of my GeometryModel3D to a tranparent color.

Model3DGroup faceVisualEntity = ModelFaces.First(modelFace => modelFace.Content.GetName() == faceName).Content as Model3DGroup;

// Breaking the 3D-model down to the constituting mesh..
//
foreach (var child in faceVisualEntity.Children)
{
    if (child is GeometryModel3D)
    {
        GeometryModel3D body = child as GeometryModel3D;
        body.Material = new DiffuseMaterial(new SolidColorBrush("#40FF0000"));
        body.BackMaterial = new DiffuseMaterial(new SolidColorBrush("#40FF0000"));
    }
}

However, what I can see in HelixViewport3D is like below.

While the sides of the box seem to be transparent, I wonder why the pipes inside the box cannot be seen. I also changed the color of the pipe walls to an opaque value, but cannot see them yet.

Answer 1

事实是，使用 HelixToolkit 的透明度功能并不能仅通过更改模型面材质的 Alpha 通道来实现。实际上，HelixToolkit 代码中有一个示例显示需要 aSortingVisual3D来支持模型的透明度。因此，我首先添加了 的实例，然后SortingVisual3D向HelixViewport3D其中添加了 Visual3D 对象，例如ModelVisual3D、LinesVisual3D等。结果，我现在可以看到如下所示。