Lec 05 Rendering Concepts and the Camera PDF

EIE 3101 Computer Animation Lec 05 Rendering Concepts and the Camera 1 Isaac Kerlow, The art of 3D computer animation and effects, 4th ed., Hoboken, N.J.: John Wiley & Sons, 2009. Chapter 6 & 7 2021/22 sem 1 2 Content Ch6 Rendering Concepts Ch7 The Camera Tutorial Camera Standard Lights S...

EIE 3101 Computer Animation Lec 05 Rendering Concepts and the Camera 1 Isaac Kerlow, The art of 3D computer animation and effects, 4th ed., Hoboken, N.J.: John Wiley & Sons, 2009. Chapter 6 & 7 2021/22 sem 1 2 Content Ch6 Rendering Concepts Ch7 The Camera Tutorial Camera Standard Lights Shadow Map 3 Rendering Concepts  Most of the visual characteristics of a simulated 3-D environment are determined during the rendering process.  When we use computers to render real or imagined scenes, we can follow specific procedures that help accomplish all the tasks required before the rendering can be completed by the computer program.  Most visual artists have to deal with a few basic elements during the image-making or rendering process.  These elements include composition, lighting, and defining surface characteristics such as color and texture. 4 Fig 6.1.2 5 Steps in the Rendering Process 6 Cameras  Cameras are a small but essential detail in the rendering process mostly because they define what we see in a particular shot, where we see it from, and how we see it. (Fig 7.1.1)  While many of the steps in composing the shot have to do with arranging and defining the objects in front of the camera, defining and positioning the camera itself marks the beginning of the rendering process. 7 The Pyramid of Vision  The pyramid of vision provides a simple way to understand some of the technical concepts involved in rendering.  The pyramid of vision, also called the cone of vision, is defined as the portion of the 3-D environment that is seen through the camera.  The pyramid of vision is defined by several parameters that are essential for controlling the position and characteristics of the camera.  This numerical information includes the point of view and the point of interest, the line of sight, the near and far clipping planes, the field of vision, the viewing angle, the focal length, and the depth of field. 8 Fig 7.2.1 The Pyramid of Vision 9 The Pyramid of Vision  Points of View and Interest  The point of view (POV), or viewing point, is the location in the scene where the camera is placed.  The point of interest (POI), or center of interest, is the location in space where the camera is focused.  The line of sight is defined as a perpendicular line that travels away from the camera, from the point of view to the point of interest  Fig 7.1.3 10 The Pyramid of Vision  Clipping Planes  The clipping planes are perpendicular to the line of sight.  The far clipping plane, also called the yon plane, defines the most distant area that can be seen by the camera.  The near clipping plane, also called the hither plane, represents the area closest to the camera that is visible to the camera.  The viewing angle defines the size relation between the near and the far clipping planes. The viewing angle also defines the width spread of the pyramid of vision and the focal length. (Fig 7.4.3) 11 The Pyramid of Vision  Field of Vision  The clipping planes truncate the pyramid of vision and define the field of vision and the image plane.  The objects contained inside the field of vision are projected onto the image plane to create a 2-D image of 3-D environment.  The relation between the width and the height of the image plane defines the aspect ratio, or proportion, of the image.  Computer-simulated cameras have a rectangular aspect ratio usually in a horizontal orientation, also called landscape format.  The portrait format evolved as the most convenient way to frame portraits of individuals and focus on their faces and/or figures. The Pyramid of Vision 12  Focal Length  The focal length of a camera controls the way in which 3-D objects are seen by the camera.  The focal length in a photographic camera is determined by the curvature and shape of the lens, and by the distance between the lens and the image plane.  Standard camera lenses have a fixed focal length, except for zoom lenses  Virtual camera lenses can simulate almost any focal length 13 The Pyramid of Vision  Depth of Field and Focus  The focal plane of a lens is the plane perpendicular to the camera that is resolved into a sharp image.  Only one plane in 3-D space can be in perfect focus when seen through any lens, but the areas that neighbor the focal plane are in focus.  The depth of field, also called DOF, is the portion of the scene in front of the camera that appears focused, and it is defined by the area between the near and the far focal planes.  In renderings with a shallow depth of field, many elements appear out of focus (Fig 7.2.3)  Scenes with ample depths of field yield images with an overall sharpness that spans from the foreground to the background (Fig 7.2.10)  Depth of fields and focus are used to direct the viewers’ attention to the relevant areas of the framed image. 14 Fig 7.2.3, 7.2.10 15 Depth of Field 1. Rendered without Depth of Field applied 2. Rendered with Depth of Field applied 16 Types of Camera Lenses  Most 3-D rendering software provides an infinite range of camera lenses that can be used for practical and stylistic purposes.  The stylistic use of employing different camera lenses is to create different moods in the scene.  The practical use of switching camera lenses is to modify the way in which the subjects fill the frame without having to move the camera. 17 Types of Camera Lenses  Photographers refer to camera lenses in terms of their focal length. (Fig 7.4.1)  Most photographic camera lenses have a fixed focal length, except for the so-called zoom lenses that contain multiple lenses and are therefore capable of a range of variable focal lengths. 18 Types of Camera Lenses  In general, lenses with a short focal length offer a wide angle of view and increased depth of field, but objects appear distant to the camera.  Inversely, lenses with a long focal length have a narrow angles of view and depths of field. 19 Types of Camera Lenses  The area of the scene that is framed within the image can be defined by:  the type of lens used (Fig 7.4.3)  the distance between the camera and the subject (Fig 7.4.4)  Both (Fig 7.4.5) 20 21 Camera Animation  The camera has a powerful storytelling effect because it leads the eyes and minds of an audience throughout the process of visual storytelling.  Animated camera moves can be based on both changes of position and orientation.  The camera moves that are based on a change of the position of the camera include a dolly, a truck, and a boom.  A truck is a translation of the camera along the horizontal axis (parallel to the view plane).  A dolly move is a translation of the camera along the depth axis (line of sight), and it usually goes in or out of the scene.  A boom (or pedestal) is a translation of the camera along its vertical axis.  Fig 11.3.1a 22 Camera Animation  The camera moves that are based on a change of the orientation of the camera include a tilt, a roll, and a pan.  A tilt is a rotation of the camera on its horizontal axis. A tilt is also called a pivot and is used to look up or look down.  A roll is created by rotating the camera around its Z axis. Roll camera moves are common when simulating fly-throughs.  A pan is a move created by rotating the camera around its vertical axis. Panning is very effective for scanning the scene from side to side while the camera remains stationary.  Fig 11.3.1b 23 Fig 11.3.1a, 11.3.1b PAN TILT DOLLY TRUCK ROLL BOOM https://boords.com/blog/16-types-ofcamera-shots-and-angles-with-gifs 24 Camera Animation  Sometimes, especially when simulating flying cameras, a tilt move is called a pitch and a pan move is called a yaw.  A zoom is a camera move that is achieved not by moving the position or orientation of the camera but by animating its focal length.