Compositing a 3D character over video footage in Maya Jean-Marc Gauthier, Spring 2008

Transcription

1 Compositing a 3D character over video footage in Maya Jean-Marc Gauthier, Spring 2008 Video footage before compositing And after compositing with an animated character This tutorial is organized as small project. We start with capturing 5 to 7 seconds of video, creating a simple 3D scene with character animation and compositing the video footage with the 3D scene inside Maya. I suggest shooting the video footage with already your 3D scene in mind. You can divide the frame between important elements for your story. For example, creating a camera angle with a low camera allows up to 50% of the frame filled with sidewalk surface. Free areas of the sidewalk can be used later by your character. Strong lighting and floor casting contracted shadows can help blending the 3D scene with the video footage. Part 1 Final Cut Pro and After Effects This part helps you to capture and prepare the background video footage that can be used as an image sequence in Maya. You can skip this part and go to the section about After Effects, if you already saved your media as a QuickTime movie or Mpg movie. The following Mac tutorial shows how to capture in Final Cut Pro, for example video clips from a mini-dv tape, 1- Setting up a new project Go to File > New Project Go to File Save Project As > Save the project in a MyName folder Go to Edit > Preferences, select MyName folder 2- Capture Go to File > Log and Capture Roll the tape to the starting point of the sequence that you plan to capture. In the Log and Capture window, press Now to start recording and Escape to stop.

2 In the clip window, select File > Save Clip As 3- Save as a QuickTime movie Go to File > Import File > add the file. Drag the clip from the Browser window to the Time Line Sequence window Go to File > Export Quicktime. Format: Quicktime Movie Under Options select the following parameters: Settings: Compressor DV-NTSC Quality Best In After Effects: Go to Composition > New Composition, create Comp1 Resolution of your choice Frame Rate to fps frames per second Duration of your choice Go to File > Import > Footage File LMB and drag the Quicktime movie icon to Comp1 Timeline

3 Make sure that the clip length matches the workspace Let s create a Sequence of images in Tiff format Go to Composition > Add to Render Queue Window will appear Select Output Module Format: TIFF sequence Select Output to > Create a new folder for rendering for example Sidewalk. Edit the file name as follows name.[####].tif This will insure that the file name can be used as an image sequence in Maya. Save inside the Sidewalk folder. Select Render Part 2 Compositing in Maya Let s go to Maya, First step, we start building a Maya scene with a plane, cubes and a sphere lit with a spot light and a directional light. In order to match the orientation of the lighting with the footage

4 Second step is to include the video footage. Third step is to make the green plane invisible but the shadows cast by objects on the green plane remain visible. In this example, we use two lights, a spot light and a directional light located in opposite directions of the planes. Left view, both lights cast shadows and the cubes have two shadows. Right view, only the spot light casts shadows because Use Depth Map Shadows is ON for spot light and is OFF for directional light. Use Depth Map Shadows is ON for spot light and is OFF for directional light.

5 Go to Window > Rendering Editors > Hypershade Select the Cameras tab MM and drag the Persp camera in the Work Area. Go to Create Maya Node > Image Planes, MMB and drag on Persp camera icon, select default.

6 Go to Work Area, Doubleclick on Image Plane 1 open the file of your choice in the Attribute Editor. Move the Persp camera in order to match - 3D green plane and sidewalk inside video footage - lighting inside video footage and spotlight in 3D scene Save your work. Let s open the file with the animated character. Parenting the animated character to an Empty Group will allow you to scale, rotate and translate the animated character at your convenience. You can also create keyframes, for example rotation of the character without altering the character animation.

7 Go to Create > Empty Group. In Outliner, parent root and character s mesh to the Empty Group. Save. Open the compositing scene. Go to File > Import, select the animated character scene.

8 Change perspective view or create a new perspective view in order to view the animated character and the whole scene without disturbing the original Persp camera with Video footage. In Outliner, select null1, the Empty Node and scale the animated character

9 In Outliner, select null1, the Empty Node and translate the animated character. You can use the 3D cubes for placement. Select the plane for the floor, for example in the Outliner window. Go to Windows > Rendering Editors > Hypershade. Go to Create Maya Node > Surface > Use Background, MMB and drag on the selected plane for the floor in the perspective window (or in any other 3D window)

10 In the Attribute Editor, you can adjust Shadow Mask in order to match the intensity of the shadow of 3D objects with the video footage. You can use the IPR rendering to render faster inside a smaller rendering window - Red box on screen.

11 Compositing a 3D character over video footage in Maya Jean-Marc Gauthier, Spring 2008 Video footage before compositing And after compositing with an animated character This tutorial is organized as small project. We start with capturing 5 to 7 seconds of video, creating a simple 3D scene with character animation and compositing the video footage with the 3D scene inside Maya. I suggest shooting the video footage with already your 3D scene in mind. You can divide the frame between important elements for your story. For example, creating a camera angle with a low camera allows up to 50% of the frame filled with sidewalk surface. Free areas of the sidewalk can be used later by your character. Strong lighting and floor casting contracted shadows can help blending the 3D scene with the video footage. Part 1 Final Cut Pro or/and After Effects This part helps you to capture and prepare the background video footage that can be used as an image sequence in Maya. You can skip this part and go to the section about After Effects, if you already saved your media as a QuickTime movie or Mpg movie. For example, using the Sanyo Xacti camera you can load the footage from the Flash drive directly in After Effects. The following Mac tutorial shows how to capture in Final Cut Pro, for example video clips from a mini-dv tape, 1- Setting up a new project Go to File > New Project Go to File Save Project As > Save the project in a MyName folder Go to Edit > Preferences, select MyName folder 2- Capture Go to File > Log and Capture Roll the tape to the starting point of the sequence that you plan to capture.

12 In the Log and Capture window, press Now to start recording and Escape to stop. In the clip window, select File > Save Clip As 3- Save as a QuickTime movie Go to File > Import File > add the file. Drag the clip from the Browser window to the Time Line Sequence window Go to File > Export Quicktime. Format: Quicktime Movie Under Options select the following parameters: Settings: Compressor DV-NTSC Quality Best In After Effects: Go to Composition > New Composition, create Comp1 Resolution of your choice Frame Rate to fps frames per second Duration of your choice Go to File > Import > Footage File LMB and drag the Quicktime movie icon to Comp1 Timeline

13 Make sure that the clip length matches the workspace Let s create a Sequence of images in Tiff format Go to Composition > Add to Render Queue Window will appear Select Output Module Format: TIFF sequence Select Output to > Create a new folder for rendering for example Sidewalk. Edit the file name as follows name.[####].tif This will insure that the file name can be used as an image sequence in Maya. Save inside the Sidewalk folder. Select Render Part 2 Compositing an animated character in Maya Let s go to Maya, First step, we start building a Maya scene with a plane, cubes and a sphere lit with a spot light and a directional light. In order to match the orientation of the lighting with the footage

14 Second step is to include the video footage. Third step is to make the green plane invisible but the shadows cast by objects on the green plane remain visible. In this example, we use two lights, a spot light and a directional light located in opposite directions of the planes. Left view, both lights cast shadows and the cubes have two shadows. Right view, only the spot light casts shadows because Use Depth Map Shadows is ON for spot light and is OFF for directional light. Use Depth Map Shadows is ON for spot light and is OFF for directional light.

15 Go to Window > Rendering Editors > Hypershade Select the Cameras tab MM and drag the Persp camera in the Work Area. Go to Create Maya Node > Image Planes, MMB and drag on Persp camera icon, select default.

16 Go to Work Area, Doubleclick on Image Plane 1 open the file of your choice in the Attribute Editor. Move the Persp camera in order to match - 3D green plane and sidewalk inside video footage - lighting inside video footage and spotlight in 3D scene Save your work. Let s open the file with the animated character. Parenting the animated character to an Empty Group will allow you to scale, rotate and translate the animated character at your convenience. You can also create keyframes, for example rotation of the character without altering the character animation.

17 Go to Create > Empty Group. In Outliner, parent root and character s mesh to the Empty Group. Save. Open the compositing scene. Go to File > Import, select the animated character scene.

18 Change perspective view or create a new perspective view in order to view the animated character and the whole scene without disturbing the original Persp camera with Video footage. In Outliner, select null1, the Empty Node and scale the animated character

19 In Outliner, select null1, the Empty Node and translate the animated character. You can use the 3D cubes for placement. Select the plane for the floor, for example in the Outliner window. Go to Windows > Rendering Editors > Hypershade. Go to Create Maya Node > Surface > Use Background, MMB and drag on the selected plane for the floor in the perspective window (or in any other 3D window)

20 In the Attribute Editor, you can adjust Shadow Mask in order to match the intensity of the shadow of 3D objects with the video footage. You can use the IPR rendering to render faster inside a smaller rendering window - Red box on screen. Part 3 Rendering Important note the Background Shader requires to use Mental Ray The perspective view. the same scene rendered with shadows mask = 1 with Mental Ray and Final Gathering

21 Shadow mask = 0.8 and Mental Ray+Final Gathering Let s check the rendering setting for Mental Ray Please note that Mental Ray has two tabs Common. and Mental Ray

22 When you scroll down the Mental ray settings, you find the Final Gathering sections. Final Gathering needs to be on in order to render the character s shadows. Now you are ready to render together the animation and the video clip. Go to Rendering > Render > Batch Render. You can find the status of your rendering and of the saved files in the lower right.

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