在WPF 3D中，我们常常需要改变一个ModelVisual3D对象的颜色。
先说说ModelVisual3D,本质上3D模型都是由一个个的三角形构成的，并且经过材质进行渲染(DiffuseMaterial) 。
这是一个ModelVisual3D的xaml代码：
<ModelVisual3D x:Name="d18"> <ModelVisual3D.Content> <GeometryModel3D x:Name="DefaultMaterial" d:Bounds="-156.412704467773,-34.2943992614746,-13.5738000869751,84.2265014648438,42.2536993026733,27.1476001739502"> <GeometryModel3D.Geometry> <MeshGeometry3D Normals="0,-1,0 0,-1,0 0,-1,0 0,-1,0 0,1,0 0,1,0 0,1,0 0,1,0 0,0,-1 0,0,-1 0,0,-1 0,0,-1 0,0,-1,, ,..."/> </GeometryModel3D.Geometry> <GeometryModel3D.Material> <DiffuseMaterial Brush="White"/> </GeometryModel3D.Material> </GeometryModel3D> </ModelVisual3D.Content>
层级结构是ModelVisual3D->ModelVisual3D.Content->GeometryModel3D->GeometryModel3D.Material
其中GeometryModel3D的Gemetry就定义了所有的坐标，将这些坐标连起来就是这个模型块的骨骼；Material就定义了这个骨骼的皮肤。
更多的解释去看msdn吧，我这里写了个通用方法修改模型的颜色：
public static class RenderExtension{ public static void SetColor(this ModelVisual3D visual3D, Brush color) { GeometryModel3D geometrymodel = visual3D.Content as GeometryModel3D; if (geometrymodel.Material is MaterialGroup) { var materialGroup = geometrymodel.Material as MaterialGroup; foreach (var groupItem in materialGroup.Children) { if (groupItem is DiffuseMaterial) { DiffuseMaterial tmpItem = groupItem as DiffuseMaterial; tmpItem.Brush = color; } } } else { DiffuseMaterial material = geometrymodel.Material as DiffuseMaterial; if (material != null) { material.Brush = color; } } }}
调用的时候只要写：visual3D.SetColor(Brushes.Red);就可以了