CGS 3034 Lecture 4 Camera Animation

Transcription

1 CGS 3034 Lecture 4 Camera Animation Introduction to Computer Aided Animation Instructor: Brent Rossen

2 Overview Depth of Field and Gobo Lighting The Imperfect Camera Maya s Perfect Camera Imperfecting: Depth of Field and Lens Flares Film Camera Aperture: F-stop Attention Changing using Depth of Field Gobo Lighting Alternative for off camera objects Leaves, Venetian Blinds, Jail Cell Bars

3 Maya s Perfect Camera Operates like a perfectly still camera in a vacuum Audiences are used to seeing flaws, even our eyes don t work perfectly Flaws and optical phenomenon (like lens flares) can help to create film like realism

4 Creating a Camera Create > Camera Rename it in the name field at the top of the channel box Switch between camera views using the Panels > Perspective and choosing from the list or use the [ and ] keys to view cameras

5 Positioning a Camera Can be done from the view of another camera using regular translation and rotation tools OR, Alt + LMB to tumble Alt + MMB to track Alt + RMB to dolly For precise positioning use the tools in View > Camera Tools

6 Undo and Bookmarks Camera undo s are not on by default, if you want to be able to undo camera movements Camera Attribute Editor > Movement Options > Undoable Movements You can bookmark a camera position so that you can always get back to it View > Bookmarks > Edit Bookmarks

7 Dolly vs. Zoom Because it is so easy to move a virtual camera Dolly and Zoom are sometimes confused in 3D Dolly: physically moving the camera forward or back (normal perspective changes) Zoom: changing the camera s focal length (eerie quality of size change without perspective change) Hitchcock s Vertigo: zooming in while dollying out or dollying in while zooming out

8 Cameras For Batch Rendering For batch rendering, you will need to specify which camera you will render from Render Settings > Image File Output and select the camera from the popup list

9 Resolution Gate and Overscan It can be difficult to see what you will be getting in you shot if your view size does not match what will render. To see exactly what will render: View > Camera Settings > Resolution Gate Often you will want to see more or less of your scene without changing the camera position, use overscan for this. Camera Attribute Editor > Display Options, change the Overscan value

10 Imperfecting - Depth of Field

11 Vacuum Camera

12 Depth of Field Camera F-stop: 8

13 Vacuum Video f-stop: infinity

14 Depth of Field f-stop: 8

15 Lens Flare & F-stop: 8

16 Film Camera Goal: mimic the feel of film Increasing the aperture: for good exposure cinematographers may need to increase the amount of available light hitting the negative F-stop: measure of the aperture Low f-stop = wide aperture (used in low light, gives small focal depth) High f-stop = tight aperture (used in high light, gives large focal depth)

17 F-stop Settings Compared: 4-8 F-stop: 4 F-stop: 8

18 F-stop Settings Compared: F-stop: 16 F-stop: 24

19 Depth of Field Howto Select Camera Node > Attribute Editor > Depth of Field Check Depth of Field Set the Focus Distance according to the object you want to have attention Set the f-stop according to the amount of light you have or the depth of field intensity you want F-stop range Low Light: 4 - Bright light: 24

20 Measuring Tools Use measuring tools to determine the distance to the attention object Create > Measure Tool > Distance Tool Use make live to snap to objects Edit > Parent the measure tool locator to the object you want it to stick to for tracking Camera Distance Alternative: Display > Heads Up Display > Object Details (Camera Distance for selected object)

21 Attention Shifts using Depth of Field You can change the depth to shift attention F-stop: 8 Depth: 12 Depth: 21

22 Optical FX Glows, halos, and lens flares oh my Select Your Light > Light Glow > Create Render Node option Note: unless you are going for something magical keep optical FX subtle, they are often and easily overused Lens Flare Check Box will turn on lens flare (the light must be aimed at your camera in the case of spotlights) IPR may help save time while changing settings

23 Gobo Lighting When you want to throw a shadow but don t want to create the object for said shadow, gobo s the tool Often used in real cinematography for: Leaves, Venetian Blinds, Jail Cell Bars Map an image to the intensity of a spotlight and you have a gobo light effect Much faster to render than raytracing the shadows of an actual transparent model

24 Gobo Lighting Original and Gobo

25 Gobo Lighting - Result

26 Wrapping Up Sometimes bad is good camera realism Use optical FX sparingly Gobos are better than nobos Project 2 focuses on practicing and enhancing the techniques you learned in project 1