Section outline

  • Motion tracking , also called  Match moving , is an essential element when integrating 3D elements with live footage. Motion tracking software is usually pretty expensive, but the Icarus application (Windows and Mac) is available for free for educational use. Icarus, which hasn't been updated for while, was later replaced by the commercial application  PFTrack . Other popular motion tracking applications are  PFMatchit  and  PFHoe (both also from The Pixel Farm),  Voodoo  (for Windows/Linux; free for non-commercial use),  SynthEyes ,  Boujou  and  3D-Equalizer  (commercial).
    ::运动跟踪,也称为匹配移动,是将3D元素与实时录像集成时的必不可少的元素.运动跟踪软件通常相当昂贵,但Icarus应用程序 (Windows和Mac) 可免费用于教育用途.Icarus,这已经没有更新,后来被商业应用程序PFTrack取代.其他流行的运动跟踪应用程序是PFMatchit和PFHoe (这两者也是来自Pixel Farm),Voodoo (Windows/Linux;免费非商业用途),SynthEyes,Boujou和3D-Equalizer (商业).

    The excellent CG prodigy  Colin Levy  hosts Icarus(by kind permission of The Pixel Farm Ltd), the Icarus import script for Blender, as well as a splendid video tutorial (see  Download Icarus and Video Tutorial ). However, I lacked a brief text tutorial about motion tracking, so I decided to write my own. This tutorial is extremely brief and high-level, and requires some previous knowledge on video editing, 3D, and Blender.
    ::优秀的CG神奇人物科林·莱维主持了Icarus (通过Pixel Farm Ltd的许可),Blender的Icarus导入脚本,以及一个精彩的视频教程 (见下载Icarus和视频教程).然而,我缺乏关于运动跟踪的简短文本教程,所以我决定写自己的.这个教程非常简短和高级,需要一些关于视频编辑,3D和Blender的先验知识.

    Note:  this tutorial was created using Mac OS X 10.5 Leopard, Blender 2.46, Icarus 2.09, and the  Icarus Import Script for Blender  v1.07e (for Blender 2.41, written by Alfredo de Greef).
    ::注意:本教程使用Mac OS X 10.5 Leopard,Blender 2.46,Icarus 2.09,以及Blender v1.07e的Icarus 导入脚本 (为Blender 2.41编写的Alfredo de Greef) 来创建.

    Tutorial
    ::导学

    Phase 1: Preparing the Video Footage
    ::第一个阶段:制作录像

    Note:  this tutorial explains the  Auto-feature Tracking  mode in Icarus. There are other options which gives more user control - see the Icarus  UserGuide.pdf  for more information.
    ::注意:本教程解释了Icarus的自动功能跟踪模式. 还有其他选择可以让用户有更多的控制权 - 查看Icarus用户指南.pdf获取更多信息.

    1. Record your video footage. Having the camera on a tripod (thus limiting to just panning/rotating) simplifies the tracking, but Icarus can handle a hand-held camera as well. Filming a background with orthogonal lines (that can align to X/Y/Z dimensions), such as a room, also helps the tracking.
      ::记录你的视频录像. 设置摄像机在三脚架上 (因此仅限于旋转/旋转) 简化了跟踪,但Icarus也可以处理手持摄像机. 拍摄一个背景与直角线 (可以对齐到X/Y/Z维度),如一个房间,也有助于跟踪.
    2. Capture/import your video footage to your computer. Icarus handles video up to DV resolution (720*576 pixels).
      ::捕捉/导入您的视频录像到您的计算机. Icarus处理视频高达DV分辨率 (720*576像素).
    3. Start the Icarus  Calibration  application (there is also a  Distortion  and a  Reconstruction  application).
      ::启动"伊卡鲁斯校准"应用程序 (还有一个"扭曲"和"重建"应用程序).
    4. Create a new project (Project->New).
      ::创建一个新项目 (项目->新).
    5. Import your video footage (Project->Import Movie).
      ::导入您的视频录像 (项目-> 导入电影).
    6. Fill in the  Camera Parameters  information in the window that pops up - especially the  Camera Motion  and the  Pixel Aspect  options.
      ::在弹出窗口中填写相机参数信息 - 特别是相机运动和像素方面选项.
    7. In the left panel, expand the group called  Coordinate Frame . You should see X Axis, Y Axis, etc.
      ::在左面板中,扩展名为坐标框架的组. 你应该看到X轴,Y轴等等.
    8. Click the Z Axis tool (blue) and mark vertical lines in your video footage. Use the X Axis (red) and Y Axis (green) tools to mark horizontal lines (up to you to decide which should be X and Y).
      ::点击Z轴工具 (蓝色) 并在视频中标记垂直线.使用X轴 (红色) 和Y轴 (绿色) 工具标记水平线 (由您决定哪个应该是X和Y).
    9. Estimate the focal length (Camera->Estimate Focal Length).
      ::估计焦距 (摄像机->估计焦距).
    10. Navigate in time in your video footage using the time slider (beneath the video image). Add more X/Y/Z marker lines on a few key frames, especially as new pieces of the background are revealed when the camera moves.
      ::在视频中使用时间滑块 (视频图像下方) 导航时间. 在一些关键上添加更多的X/Y/Z标记线,特别是当摄像机移动时,会发现新的背景片段.
    11. Save your project (Project->Save).
      ::保存您的项目 (项目-> 保存).
    12. Start the tracking process (Camera->Track and Calibrate). This will take some time.
      ::启动追踪过程 (摄像机->追踪和校准). 这需要一些时间.
    13. Export the results in human-readable form (Project->Export 3D Motion, select  Human Readable (*.txt)  as file type).
      ::将结果导出为人类可读的形式 (Project->导出3D动作,选择人类可读 (*.txt) 作为文件类型).

    Phase 2: Importing the Motion Tracking Data into Blender
    ::阶段2:将运动跟踪数据导入混器

    1. Start Blender, and open a Text Editor view.
      ::启动Blender, 打开一个文本编辑器视图.
    2. Open the Icarus import script  ICARUS_import241.py  (File->Open).
      ::打开"伊卡鲁斯"导入脚本ICARUS_import241.py (文件->打开).
    3. Start the script (File->Run Python Script). You should now see the Icarus Import screen.
      ::现在你应该看到"伊卡鲁斯导入"的屏幕.
    4. Press the  FSEL  button, and open the results you exported from Icarus.
      ::按FSEL按, 打开从Icarus导出的结果.
    5. Press the  Create Curves  button. This imports the camera motion from the Icarus data and applies it to the Blender default camera.
      ::按下"创建曲线"按. 这将从Icarus数据中导入摄像机运动并将其应用到Blender的默认摄像机.
    6. Press the  Feature Points Mesh  button. This imports 3D shape dots from the Icarus data, which helps as reference when you want to align your own 3D elements to the video footage.
      ::按下"特征点网格"按. 这将从Icarus数据中导入3D形状点,当您想要将自己的3D元素与视频镜头对齐时,这有助于参考.

    You are now ready to add your own 3D elements to the Blender scene.
    ::现在您可以为Blender场景添加您自己的3D元素.

    Phase 3: Compositing 3D Elements on top of Video Footage
    ::阶段3:在视频录像上组合3D元素

    If you want to easily composite the 3D elements on top of an image, you can add the image as the rendering back buffer in Blender (Scene tab in the Buttons view). However, this doesn't work for videos, so we need another solution.
    ::如果您想在图像顶部轻松组合3D元素,您可以在Blender中添加图像作为染回缓冲区 (按视图中的场景选项卡). 然而,这对视频不起作用,因此我们需要另一个解决方案.

    1. In Blender, switch to  SR:4 - Sequence  in the layout dropdown menu at the top of the screen.
      ::在Blender中,在屏幕顶部的布局下拉菜单中切换到SR:4 - 序列.
    2. In the  Video Sequence Editor  view (middle of screen), add your video file (Add->Movie). Move the new strip to layer 1, frame 1.
      ::在视频序列编辑器视图 (屏幕中间),添加您的视频文件 (添加-> 电影). 将新条带移动到1层,1.
    3. Add the current scene to the sequence (Add->Scene, Scene). Move the new strip to layer 2, frame 1.
      ::将当前场景添加到序列 (添加->场景,场景). 将新条带移动到2层,1.
    4. Select the scene strip on the second layer (right-click).
      ::在第二层选择场景条 (右键).
    5. Open the  Scene  panel in the Buttons view, and then open the  Sequencer  sub-panel.
      ::然后打开序列分组.
    6. Change the  Blend Mode  dropdown from  Replace  to  Alpha Over . Your 3D elements should now render over the background video in the top-right preview screen.
      ::现在,您的3D元素应该在右上方的预览屏幕上呈现背景视频.
    7. In the Render panel, enable  Do Sequence  just below the ANIM button. This will enable the background video when rendering.
      ::在染面板中,在ANIM按下方启用"执行序列". 这将在染时启用背景视频.

    Troubleshooting
    ::解决问题

    • If your imported Feature Points Mesh looks a bit spherical, you need to generate camera distortion data using the Icarus  Distortion  application.
      ::如果您的导入的特征点网看起来有点球形, 您需要使用Icarus Distortion应用程序生成相机扭曲数据.