Which algorithm is used for visible surface detection?

Which algorithm is used for visible surface detection?

We must remove these hidden surfaces to get a realistic screen image. The identification and removal of these surfaces is called Hidden-surface problem. In this paper I review some visible surface detection algorithms like Z buffer method, Area subdivision method, Scan line method etc.

What algorithm is used in visibility and occlusion test in CG?

z-pyramid
The z-pyramid is used to test visibility of octree bounding boxes. Zhang et al. (1997) proposed an algorithm that replaces the z-pyramid by a hierarchical occlusion map and a depth estimation buffer. This approach was further studied by Aila (2000).

What is visible surface determination in computer graphics?

In 3D computer graphics, hidden-surface determination (also known as shown-surface determination, hidden-surface removal (HSR), occlusion culling (OC) or visible-surface determination (VSD)) is the process of identifying what surfaces and parts of surfaces can be seen from a particular viewing angle.

How does the z-buffer algorithm determine which surface are hidden?

Z-buffer, which is also known as the Depth-buffer method is one of the commonly used method for hidden surface detection. It is an Image space method. Image space methods are based on the pixel to be drawn on 2D. For these methods, the running time complexity is the number of pixels times number of objects.

Why hidden surface algorithms are needed?

The purpose of hidden surface algorithms is to determine which surfaces are obstructed by other surfaces in order to display only those surfaces visible to the eye. In theory, hidden surface algorithms are required for all types of surfaces; in practice, we shall restrict our attention to polygonal models.

How does the Z-buffer algorithm determine which surface are hidden?

Which of the following is hidden surface algorithm?

We shall examine five of the most common hidden surface algorithms: z-buffer, scan line, ray casting, depth sort, and bsp-tree. The z-buffer and scan line algorithms are image Page 2 space algorithms; the depth sort and bsp-tree algorithms are object space algorithms.

What do you mean by hidden surface removal?

The hidden surface removal is the procedure used to find which surfaces are not visible from a certain view. A hidden surface removal algorithm is a solution to the visibility issue, which was one of the first key issues in the field of three dimensional graphics.

What is the purpose of z-buffer algorithm?

A depth buffer, also known as a z-buffer, is a type of data buffer used in computer graphics to represent depth information of objects in 3D space from a particular perspective. Depth buffers are an aid to rendering a scene to ensure that the correct polygons properly occlude other polygons.

Which is an example of visible surface determination?

For example if you wish to make an open-topped box – the inside and the ouside of the box both need to be visible, so either two sets of polygons must be generated, one set facing out and another facing in, or back-face culling must be turned off to draw that object. in OpenGL back-face culling is turned on using:

How is the area subdivision method used in surface detection?

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.

How is depth calculated in visible surface detection?

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. Two important tables, edge table and polygon table, are maintained for this.

How is visible surface detection a time consuming process?

It is time consuming process. 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.