A process for the perspective representation of objects on the picture screen of a numerically controlled machine tool is described in which the object is resolved into a series of sections which are represented successively with a given perspective offset. In order to avoid the representation of covered edges of these sections, the contours of the individual section surfaces are checked prior to being represented in order to determine whether or not they overlap a previously represented contour. This checking occurs through a simple coordinate comparison, taking into account the actual perspective shift between sections.
From a two-dimensional image of an object displayed on a screen, a three-dimensional shape of the object is easily extracted. A normal vector with respect to a surface of the object in a three-dimensional system corresponding to one surface of the columnar object displayed as the two-dimensional image on the screen and three-dimensional coordinates of at least one point included in the surface are calculated, and based on the calculation result, the surface is extracted, a height of the columnar body having the surface as its bottom is set to form an object.
A method of displaying a structure (SML) three-dimensionally, in which a rectangular parallelepiped (RP), having on each of its sides distances (L.sub.x, L.sub.y, L.sub.z) between minimum and maximum positions along each axis of a structure (SML) is constituted by a set of a number of unit solids, e.g., unit cubes (UC), of the same shape and same dimensions. The structure is represented by information indicating whether each unit solid is part of the structure (SML). Individual ones of the unit solids constituting the structure (SML) are displayed in order starting from unit solids seen on a the front side of the structure. The face of a unit solid overlapping a face of a unit solid already displayed is not displayed; instead, only the visually foremost faces thereof are displayed, thereby displaying a perspective view of the three-dimensional structure (SML).
A computer aided design (CAD) system has the capability of operating in either a 2D or a 3D mode. In 2D mode, the system uses only instructions contained in a 2D instruction memory and executes only instructions relating to 2D geometry. Upon receipt of a command relating to 3D geometry, the system performs a 2D to 3D transformation, performs a topolgy check, transfers control to a 3D instruction memory and performs instructions relating to 3D geometry.
A computer graphics hidden surface removal system and process are provided for processing a display list representing a plurality of objects to provide an image on a display device. A primary viewing volume is initially determined from a desired viewpoint by defining top, bottom, left side, right side, primary far and primary near clipping planes. The viewing volume is then divided into a plurality of slices including a first slice at the primary far clipping plane and a last slice at the primary near clipping plane. The other slices are in between. Signals representing portions of the objects found in each of the slices are loaded into a display memory buffer one slice at a time progressing sequentially through the slices starting with the first slice and ending with the last slice.
Object spaces which mechanize higher order relationships between attributes which describe a particular problem domain. An abstract object description defined by a set of attributes and their corresponding values is transformed into a mixed-resolution, N-dimensional object space. The mixed-resolution, N-dimensional object space represents a mechanized, logically encoded expression of attribute relationships that can be visualized. The method and apparatus interleave the frame to generate an object descriptor and generate from the frame and the object descriptor, encoded names of spatial locations for each of the N dimensions of the mixed-resolution, N-dimensional, object space, conforming to a primary form of a reflected binary code. A virtual image of the N-dimensional, object space is generated from the dimensional-spatial locations and resolution-spatial locations, and attribute values corresponding to a region of the virtual image may be selected for display.
