事先说明：本文使用的是WPF程序自带的3d功能，想要用winform实现加载3d模型的可以退散了。
先上效果图吧。
我导入了两个模型，一个汽车和一个美女，都是在网上下载的obj格式的文件。导入之后调整了2个模型之间的位置关系，又添加了鼠标滚轮缩放，旋转的功能，这样我们就可以方便查看模型的各个细节了。
C#动态读取obj文件，加载的基本思路就是打开文件，解析obj格式，生成ModelVisual3D。我这里使用的是一个网上别人写的WavefrontObjLoader.cs。代码比较复杂，我们没必要全部看懂，只要会用就够了！
将WavefrontObjLoader.cs导入项目中
在初始化事件中加载模型并显示。使用的大概方式很简单，如下。
//new一个loader对象
WavefrontObjLoader wfl = new WavefrontObjLoader();
//ModelVisual3DWithName是WavefrontObjLoader定义的继承ModelVisual3D的对象，直接使用ModelVisual3D也是可以的
//导入obj，第一个模型命名为m
ModelVisual3DWithName m = wfl.LoadObjFile(@"C:\Users\hasee\Desktop\WpfApplication2\WpfApplication2\Lancer_Evolution_10.obj");
m.Content = myModel3DGroup;
//导入obj，第二个模型命名为n
var n = wfl.LoadObjFile(@"C:\Users\hasee\Desktop\WpfApplication2\WpfApplication2\精细人体.obj");
n.Content = myModel3DGroup;
//将两个模型添加到场景中
vp.Children.Add(m);
vp.Children.Add(n);
//vp是在xaml中定义的viewport3Dxaml中也是很简单，设置如下：
<Window x:Class="WpfApplication2.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
MouseMove="Window_MouseMove"
Title="MainWindow" Height="350" Width="525">
<Grid x:Name="lay" Background="Azure" MouseWheel="VP_MouseWheel">
<Viewport3D x:Name="vp"
MouseLeftButtonDown="vp_MouseLeftButtonDown" Margin="0,31,0.4,-0.2">
<Viewport3D.Camera>
<PerspectiveCamera FieldOfView="45" FarPlaneDistance="100" LookDirection="0,0,-3.4142135623731" NearPlaneDistance="0.1" Position="0,0,3.4142135623731" UpDirection="0,1,0"/>
</Viewport3D.Camera>
</Viewport3D>
</Grid>
</Window>
这样就实现了加载，下面是全部实现旋转和缩放，全部代码如下
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Media.Media3D;
using System.Windows.Media.Animation;
using System.Windows.Media.Effects;
namespace WpfApplication2
{
public partial class MainWindow : Window
{
//声明摄像头
PerspectiveCamera myPCamera;
//鼠标灵敏度调节
double mouseDeltaFactor = 0.4;
public MainWindow()
{
InitializeComponent();
//摄像头
myPCamera = new PerspectiveCamera();
myPCamera.Position = new Point3D(0, 0, 200);
myPCamera.LookDirection = new Vector3D(0, 0, -1);
myPCamera.FieldOfView = 1000;
vp.Camera = myPCamera;
Model3DGroup myModel3DGroup = new Model3DGroup();
//光源
//AmbientLight （自然光）
//DirectionalLight （方向光）
//PointLight （点光源）
//SpotLight （聚光源）
DirectionalLight myDirectionalLight = new DirectionalLight();
myDirectionalLight.Color = Colors.White;
myDirectionalLight.Direction = new Vector3D(0.61, 0.5, 0.61);
myModel3DGroup.Children.Add(myDirectionalLight);
//DirectionalLight myDirectionalLight2 = new DirectionalLight();
//myDirectionalLight2.Color = Colors.White;
//myDirectionalLight2.Direction = new Vector3D(0.61, 0.5, 0.61);
//myModel3DGroup.Children.Add(myDirectionalLight2);
//new一个loader对象
WavefrontObjLoader wfl = new WavefrontObjLoader();
//ModelVisual3DWithName是WavefrontObjLoader定义的继承ModelVisual3D的对象，直接使用ModelVisual3D也是可以的
//导入obj，第一个模型命名为m
ModelVisual3DWithName m = wfl.LoadObjFile(@"C:\Users\hasee\Desktop\WpfApplication2\WpfApplication2\Lancer_Evolution_10.obj");
m.Content = myModel3DGroup;
//导入obj，第二个模型命名为n
var n = wfl.LoadObjFile(@"C:\Users\hasee\Desktop\WpfApplication2\WpfApplication2\精细人体.obj");
n.Content = myModel3DGroup;
//下面是调整n的位置，初学者可以先注释掉。
var tt = new TranslateTransform3D();
tt.OffsetX = 110;
tt.OffsetZ = -50;
tt.OffsetY =-100;
var tr = new RotateTransform3D();
tr.Rotation = new AxisAngleRotation3D(new Vector3D(1, 0, 0), 90);
var tr2 = new RotateTransform3D();
tr2.Rotation= new AxisAngleRotation3D(new Vector3D(0, 0, 1), -45);
var ts = new ScaleTransform3D();
ts.ScaleX = 1.5;
ts.ScaleY = 1.5;
ts.ScaleZ = 1.6;
var tg = new Transform3DGroup();
tg.Children.Add(tr); tg.Children.Add(tr2); tg.Children.Add(tt); tg.Children.Add(ts);
n.Transform = tg;
//将两个模型添加到场景中
vp.Children.Add(m);
vp.Children.Add(n);
//添加鼠标事件，用于显示隐藏光晕特效
vp.MouseEnter += Vp_MouseEnter;
vp.MouseLeave += Vp_MouseLeave;
}
private void Vp_MouseLeave(object sender, MouseEventArgs e)
{
vp.Effect = null;
}
private void Vp_MouseEnter(object sender, MouseEventArgs e)
{
DropShadowEffect BlurRadius = new DropShadowEffect();
BlurRadius.BlurRadius = 20;
BlurRadius.Color = Colors.Yellow;
BlurRadius.Direction = 0;
BlurRadius.Opacity = 1;
BlurRadius.ShadowDepth = 0;
vp.Effect = BlurRadius;
}
public HitTestResultBehavior HTResult(HitTestResult rawresult)
{
//MessageBox.Show(rawresult.ToString());
// RayHitTestResult rayResult = rawresult as RayHitTestResult;
RayHitTestResult rayResult = rawresult as RayHitTestResult;
if (rayResult != null)
{
//RayMeshGeometry3DHitTestResult rayMeshResult = rayResult as RayMeshGeometry3DHitTestResult;
RayHitTestResult rayMeshResultrayResult = rayResult as RayHitTestResult;
if (rayMeshResultrayResult != null)
{
//GeometryModel3D hitgeo = rayMeshResult.ModelHit as GeometryModel3D;
var visual3D = rawresult.VisualHit as ModelVisual3D;
//do something
}
}
return HitTestResultBehavior.Continue;
}
//鼠标位置
Point mouseLastPosition;
private void vp_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
mouseLastPosition = e.GetPosition(this);
//RayHitTestParameters hitParams = new RayHitTestParameters(myPCamera.Position, myPCamera.LookDirection);
//VisualTreeHelper.HitTest(vp.Children[0], null, ResultCallback, hitParams);
//下面是进行点击触发检测，可忽略，注释
Point3D testpoint3D = new Point3D(mouseLastPosition.X, mouseLastPosition.Y, 0);
Vector3D testdirection = new Vector3D(mouseLastPosition.X, mouseLastPosition.Y, 100);
PointHitTestParameters pointparams = new PointHitTestParameters(mouseLastPosition);
RayHitTestParameters rayparams = new RayHitTestParameters(testpoint3D, testdirection);
//test for a result in the Viewport3D
VisualTreeHelper.HitTest(vp, null, HTResult, pointparams);
}
//鼠标旋转
private void Window_MouseMove(object sender, MouseEventArgs e)
{
if (Mouse.LeftButton == MouseButtonState.Pressed)//如果按下鼠标左键
{
Point newMousePosition = e.GetPosition(this);
if (mouseLastPosition.X != newMousePosition.X)
{
//进行水平旋转
HorizontalTransform(mouseLastPosition.X < newMousePosition.X, mouseDeltaFactor);//水平变换
}
if (mouseLastPosition.Y != newMousePosition.Y)// change position in the horizontal direction
{
//进行垂直旋转
VerticalTransform(mouseLastPosition.Y > newMousePosition.Y, mouseDeltaFactor);//垂直变换
}
mouseLastPosition = newMousePosition;
}
}
//鼠标滚轮缩放
private void VP_MouseWheel(object sender, MouseWheelEventArgs e)
{
double scaleFactor = 13;
//120 near , -120 far
System.Diagnostics.Debug.WriteLine(e.Delta.ToString());
Point3D currentPosition = myPCamera.Position;
Vector3D lookDirection = myPCamera.LookDirection;//new Vector3D(camera.LookDirection.X, camera.LookDirection.Y, camera.LookDirection.Z);
lookDirection.Normalize();
lookDirection *= scaleFactor;
if (e.Delta == 120)//getting near
{
//myPCamera.FieldOfView /= 1.2;
if ((currentPosition.X + lookDirection.X) * currentPosition.X > 0)
{
currentPosition += lookDirection;
}
}
if (e.Delta == -120)//getting far
{
//myPCamera.FieldOfView *= 1.2;
currentPosition -= lookDirection;
}
Point3DAnimation positionAnimation = new Point3DAnimation();
positionAnimation.BeginTime = new TimeSpan(0, 0, 0);
positionAnimation.Duration = TimeSpan.FromMilliseconds(100);
positionAnimation.To = currentPosition;
positionAnimation.From = myPCamera.Position;
positionAnimation.Completed += new EventHandler(positionAnimation_Completed);
myPCamera.BeginAnimation(PerspectiveCamera.PositionProperty, positionAnimation, HandoffBehavior.Compose);
}
void positionAnimation_Completed(object sender, EventArgs e)
{
Point3D position = myPCamera.Position;
myPCamera.BeginAnimation(PerspectiveCamera.PositionProperty, null);
myPCamera.Position = position;
}
// 垂直变换
private void VerticalTransform(bool upDown, double angleDeltaFactor)
{
Vector3D postion = new Vector3D(myPCamera.Position.X, myPCamera.Position.Y, myPCamera.Position.Z);
Vector3D rotateAxis = Vector3D.CrossProduct(postion, myPCamera.UpDirection);
RotateTransform3D rt3d = new RotateTransform3D();
AxisAngleRotation3D rotate = new AxisAngleRotation3D(rotateAxis, angleDeltaFactor * (upDown ? 1 : -1));
rt3d.Rotation = rotate;
Matrix3D matrix = rt3d.Value;
Point3D newPostition = matrix.Transform(myPCamera.Position);
myPCamera.Position = newPostition;
myPCamera.LookDirection = new Vector3D(-newPostition.X, -newPostition.Y, -newPostition.Z);
//update the up direction
Vector3D newUpDirection = Vector3D.CrossProduct(myPCamera.LookDirection, rotateAxis);
newUpDirection.Normalize();
myPCamera.UpDirection = newUpDirection;
}
// 水平变换：
private void HorizontalTransform(bool leftRight, double angleDeltaFactor)
{
Vector3D postion = new Vector3D(myPCamera.Position.X, myPCamera.Position.Y, myPCamera.Position.Z);
Vector3D rotateAxis = myPCamera.UpDirection;
RotateTransform3D rt3d = new RotateTransform3D();
AxisAngleRotation3D rotate = new AxisAngleRotation3D(rotateAxis, angleDeltaFactor * (leftRight ? 1 : -1));
rt3d.Rotation = rotate;
Matrix3D matrix = rt3d.Value;
Point3D newPostition = matrix.Transform(myPCamera.Position);
myPCamera.Position = newPostition;
myPCamera.LookDirection = new Vector3D(-newPostition.X, -newPostition.Y, -newPostition.Z);
}
}
}事实上，fontwaveloader这个类可以很方便的生成DLL文件，使用方式是一样的，这样vb语言也可以使用它加载obj了，我已经测试成功了。
c#工程文件下载：
https://pan.baidu.com/s/1o7A5o8q
下面是用vb使用dll加载的3d模型代码
https://pan.baidu.com/s/1ge5t5Bl【提取码：9crv】
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