Which algorithm is used for hidden line removal?
The hidden-surface algorithm, using n2/log n CREW PRAM processors, is work-optimal. The hidden-line algorithm uses n2 exclusive read, exclusive write (EREW) PRAM processors. The EREW model is the PRAM variant closest to real machines.
Which methods are used for hidden surface elimination?
There are two approaches for removing hidden surface problems − Object-Space method and Image-space method. The Object-space method is implemented in physical coordinate system and image-space method is implemented in screen coordinate system.
Which is the best hidden surface removal algorithm?
Discussion Forum
| Que. | The best hidden surface removal algorithm is? |
|---|---|
| b. | Area subdivision |
| c. | Depends on the application |
| d. | painters |
| Answer:Depends on the application |
What do you understand by hidden line and hidden surface elimination techniques?
Hidden Line Removal – assumes that objects are modeled with lines. – lines are created where surfaces meet – if only the visible surfaces are drawn, the invisible lines are automatically eliminated.
What is a hidden line?
A hidden line, also known as a hidden object line is a medium weight line, made of short dashes about 1/8” long with 1/16”gaps, to show edges, surfaces and corners which cannot be seen. Sometimes they are used to make a drawing easier to understand.
Why are hidden surface algorithms needed?
Hidden-surface determination is necessary to render a scene correctly, so that one may not view features hidden behind the model itself, allowing only the naturally viewable portion of the graphic to be visible.
Which algorithm is used for visible surface detection?
A simple ray-tracing algorithm can be used to find visible surfaces, as opposed to a more complicated algorithm that can be used to generate those o-so-pretty images. Ray tracing is an image based algorithm. For every pixel in the image, a ray is cast from the center of projection through that pixel and into the scene.
What is Painter method?
The painter’s algorithm creates images by sorting the polygons within the image by their depth and placing each polygon in order from the farthest to the closest object. Similarly, the painter’s algorithm sorts all the polygons in a scene by their depth and then paints them in this order, farthest to closest.
How do I find hidden lines?
Figure 5: Use of dashed lines to represent edges hidden in views of a complicated object. Encyclopædia Britannica, Inc. In Figure 5 the hidden lines in the views could be identified by visualizing the object, a process that can be quite difficult for complicated objects.
What is the requirement of visible surface detection algorithms?
It is an image-space method to identify visible surface. This method has 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.
How many types of hidden surface algorithm are?
We have discussed five different hidden surface algorithms: z-buffer, scan line, ray casting, depth sort, and bsp-tree. Two key ideas are applied to help increase the speed of these algorithms: sorting of edges by depth, and pixel coherence for depth and intensity.