When we view a picture containing non-transparent objects and surfaces, then we cannot see those objects from view which are behind from objects closer to eye. The identification and removal of these surfaces is called Hidden-surface problem.Likewise, why do we need hidden surface algorithms?
Hidden-surface determination is a process by which surfaces that should not be visible to the user (for example, because they lie behind opaque objects such as walls) are prevented from being rendered. Despite advances in hardware capability, there is still a need for advanced rendering algorithms.
Also, what is Z buffer technique? Z-buffering, also known as depth buffering, is a technique in computer graphics programming. It is used to determine whether an object (or part of an object) is visible in a scene. It can be implemented either in hardware or software, and is used to increase rendering efficiency.
Then, what is visible surface?
Visible-Surface Detection Methods. Problem definition of Visible-Surface Detection Methods: To identify those parts of a scene that are visible from a chosen viewing position. Surfaces which are obscured by other opaque surfaces along the line of sight (projection) are invisible to the viewer.
What is depth comparison computer graphics?
In this method each surface is processed separately one pixel position at a time across the surface. The depth values for a pixel are compared and the closest (smallest z) surface determines the colour to be displayed in the frame buffer. It is applied very efficiently on surfaces of polygon.
What is image space?
Medical Definition of image space : a space that is associated with an optical system and consists of points of which each is an image of a corresponding point in the space in which the objects being imaged reside.What is depth value?
Depth value precision The depth buffer contains depth values between 0.0 and 1.0 and it compares its content with the z-values of all the objects in the scene as seen from the viewer. These z-values in view space can be any value between the projection-frustum's near and far plane.What is shading in 3d?
In computer graphics, shading refers to the process of altering the color of an object/surface/polygon in the 3D scene, based on things like (but not limited to) the surface's angle to lights, its distance from lights, its angle to the camera and material properties (e.g. bidirectional reflectance distribution functionWhat is an active edge list in the scan line algorithm?
Scan Line Algorithm. It is an image space algorithm. It processes one line at a time rather than one pixel at a time. Active Edge List (AEL) contain edges a given scan line intersects during its sweep. The active edge list (AEL) should be sorted in increasing order of x.What is occlusion culling?
Occlusion Culling is a feature that disables rendering of objects when they are not currently seen by the camera because they are obscured (occluded) by other objects.What is object space and image space?
Object space is the 3 dimensional space in which a graphic object is defined. Image space is the projection of the object defined in 3D to two dimensional screen space. There are algorithms to eliminate hidden surfaces in (1) Object space, as well as in (2) Image space.What is back face removal in computer graphics?
A simple object space algorithm is Back-Face removal (or back face cull) where no faces on the back of the object are displayed. Since in general about half of the faces of objects are are back faces this algorithm will remove about half of the total polygons in the image.What is back face detection in computer graphics?
Back-Face detection, also known as Plane Equation method, is an object space method in which objects and parts of objects are compared to find out the visible surfaces. If this normal vector is pointing away from the center of projection, then it is a back face and can not be seen by the viewer.How do you identify visible lines and surfaces?
Scan-Line Method It is an image-space method to identify visible surface. This method has a depth information for only single scan-line. In order to require one scan-line of depth values, we must group and process all polygons intersecting a given scan-line at the same time before processing the next scan-line.What is 3d object representation?
Objects are represented as a collection of surfaces. 3D object representation is divided into two categories. Boundary Representations B−reps − It describes a 3D object as a set of surfaces that separates the object interior from the environment.What is painter's algorithm in computer graphics?
The painter's algorithm, also known as a priority fill, is one of the simplest solutions to the visibility problem in 3D computer graphics. The painter's algorithm sorts all the polygons in a scene by their depth and then paints them in this order, farthest to closest.What do you mean by clipping in computer graphics?
Clipping, in the context of computer graphics, is a method to selectively enable or disable rendering operations within a defined region of interest. Mathematically, clipping can be described using the terminology of constructive geometry. Clip regions are commonly specified to improve render performance.What is area subdivision method in computer graphics?
Area Subdivision method. The area-subdivision method takes advantage by locating those view areas that represent part of a single surface. Divide the total viewing area into smaller and smaller rectangles until each small area is the projection of part of a single visible surface or no surface at all.What is polygon clipping in computer graphics?
Sutherland-Hodgeman Polygon Clipping: It is performed by processing the boundary of polygon against each window corner or edge. First of all entire polygon is clipped against one edge, then resulting polygon is considered, then the polygon is considered against the second edge, so on for all four edges.What do you mean by image depth in computer graphics?
Depth Images are viable representations that can be computed from the real world using cameras and/or other scanning devices. The depth map gives a visibility-limited model of the scene and can be rendered easily using graphics techniques. A set of Depth Images can provide hole-free rendering of the scene.What is blobby objects in computer graphics?
"In Computer Graphics, blobby objects are the objects which are non-rigid and do not retain their fixed size. Blobby objects (as is obvious by their name) are the objects which change their shape and size on the basis of their states.What is a depth stencil?
A stencil buffer is an extra data buffer, in addition to the color buffer and Z-buffer, found on modern graphics hardware. The buffer is per pixel, and works on integer values, usually with a depth of one byte per pixel. In the simplest case, the stencil buffer is used to limit the area of rendering (stenciling). 
