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公开(公告)号：DE69030618T2
公开(公告)日：1997-10-23
申请号：DE69030618
申请日：1990-12-06
Applicant: IBM
Inventor： DOI AKIO , KOIDE AKIO
Abstract: For displaying 3-D objects such as iso-surfaces, polygons are generated and drawn simultaneously by processing cells (elements) spanned by grids in the order of decreasing distance from a current view point. The elements are divided into five or six tetrahedrons (sub-elements) and iso-surfaces are generated in each tetrahedron. This technique enables the rapid displaying of iso-surfaces from 3-D grid data with hidden surfaces processed, without the need for a depth buffer memory.
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公开(公告)号：DE69030618D1
公开(公告)日：1997-06-05
申请号：DE69030618
申请日：1990-12-06
Applicant: IBM
Inventor： DOI AKIO , KOIDE AKIO
Abstract: For displaying 3-D objects such as iso-surfaces, polygons are generated and drawn simultaneously by processing cells (elements) spanned by grids in the order of decreasing distance from a current view point. The elements are divided into five or six tetrahedrons (sub-elements) and iso-surfaces are generated in each tetrahedron. This technique enables the rapid displaying of iso-surfaces from 3-D grid data with hidden surfaces processed, without the need for a depth buffer memory.
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公开(公告)号：CA2032847C
公开(公告)日：1996-05-14
申请号：CA2032847
申请日：1990-12-20
Applicant: IBM
Inventor： DOI AKIO , KOIDE AKIO
Abstract: This disclosure describes a method for displaying a three-dimensional object wherein a three-dimensional space is virtually divided into a plurality of elements arranged according to predetermined directions, each of said elements being virtually divided into an equal number of sub-elements, and the positional relationship of sub-elements in one element is common to all the elements. Graphics data of one polygon are generated in each sub-element, and a 3D object is displayed on the basis of the generated graphics data of polygons. The method includes the steps of providing data on the position of a view point and a reference point, and generating data for a view vector connecting the view point and the reference point; determining the depth order of said elements on the basis of the view vector data and the vector data on the arrangement directions of said elements; determining the depth order of sub-elements in one element, which is commonly applicable to all the elements, on the basis of data on the position of the sub-elements contained in the element and the view point; and transferring the generated graphics data of polygons to a display apparatus in order of the depth of said elements and of sub-elements in one element.
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公开(公告)号：CA1304525C
公开(公告)日：1992-06-30
申请号：CA571400
申请日：1988-07-07
Applicant: IBM
Inventor： DOI AKIO
Abstract: A method of generating images of an object to be projected on a projective plane uses a ray-tracing method which comprises the steps of, for each pel, assuming a ray emitted from a selected viewpoint, then determining reflected and refracted rays emitted from the intersection of the assumed ray and its intersection with an object, and sequentially determining the intersection points of successive reflected and/or refractive rays with the object. JA9-87-011
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公开(公告)号：CA2032847A1
公开(公告)日：1991-06-29
申请号：CA2032847
申请日：1990-12-20
Applicant: IBM
Inventor： DOI AKIO , KOIDE AKIO
Abstract: For displaying 3-D objects such as iso-surfaces, polygons are generated and drawn simultaneously by processing cells (elements) spanned by grids in the order of decreasing distance from a current view point. The elements are divided into five or six tetrahedrons (sub-elements) and iso-surfaces are generated in each tetrahedron. This technique enables the rapid displaying of iso-surfaces from 3-D grid data with hidden surfaces processed, without the need for a depth buffer memory.
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Patent Agency Ranking
公开(公告)号：JPH0721405A
公开(公告)日：1995-01-24
申请号：JP14445993
申请日：1993-06-16
Applicant: IBM JAPAN
Inventor： MIYAZAWA TATSUO , DOI AKIO , OYAMADA KOJI
Abstract: PURPOSE:To increase the value of a color on a part having large mirror reflection and to attain sufficient highlight expression by forming an object image whose opacity is increased based upon the size of a mirror reflection component. CONSTITUTION:Additional opacity alphas concerned and original opacity alphan are respectively led out from respective tables 11, 12 based upon the data value 17 of volume data 15, the value ¦N¦ 23 of a gradient vector is calculated and an adjusting function G concerned is led out from a table 13 based upon the value ¦N¦ 23. A previously found mirror reflection component 21 is multiplied by the additional opacity alphas the original opacity alphan is added to the multiplied value and the added result is multiplied by the function G to find out opacity alphai 24 emphasized at its sampling point. Thus color/opacity volume Cialphai constituted of the color value Ci of the found sampling point and the emphasized opacity alphai.
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公开(公告)号：JPH03202981A
公开(公告)日：1991-09-04
申请号：JP33889789
申请日：1989-12-28
Applicant: IBM
Inventor： DOI AKIO , KOIDE AKIO
IPC: G06T15/40
Abstract: PURPOSE: To shorten sorting processing time by deciding the depth order of elements based on viewpoint vector data generated by means of giving position data on a viewpoint and watch point and vector data in the arranging direction of elements and transferring picture data of a generated polygon to a display device. CONSTITUTION: Data is virtually divided into the equal number of auxiliary elements of more than two. The position relations of the auxiliary elements in one element is made common in all the elements and picture data of one polygon is generated at every auxiliary element. At the time of displaying the picture based on picture data on the generated polygon, the depth order of the auxiliary elements in one element, which is common to all the elements, is decided based on position data of the auxiliary elements and the watch point, which are contained in one arbitrary element. Picture data of the generated polygon is transferred to the display device in accordance with the depth order of the element and the depth order of the auxiliary elements in one element. Thus, a three-dimensional graphic can be displayed at high speed.
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公开(公告)号：JPS6431279A
公开(公告)日：1989-02-01
申请号：JP17609987
申请日：1987-07-16
Applicant: IBM
Inventor： DOI AKIO
IPC: G06T15/00
Abstract: PURPOSE: To trace light rays at a high speed by setting a space area including an object to be displayed, dividing the space area into plural cells and judging whether the surface of the object is included in each cell or not. CONSTITUTION: Out of cells obtained by dividing an area 42 including an object 44 to be displayed, only cells including the surface 50 of the object 44 are registered. The calculation of intersections is executed only for a rectangular parallelepiped including the surface. Thereby, the time required for the display of the object 44 can be shortened. Although an area including the object 44 and cells obtained by dividing the area are not limited to rectangular parallelepipeds, rectangular parallelepipes are favorable at the time of considering realization.
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公开(公告)号：JPH0896161A
公开(公告)日：1996-04-12
申请号：JP22176194
申请日：1994-09-16
Applicant: IBM
Inventor： DOI AKIO , SHIMADA KENJI , ITO TAKAYUKI
Abstract: PURPOSE: To increase the rendering speed of the Radio City Method by improving the mesh generating efficiency of the method by holding the irradiation state of each light source at every area formed by luminance discontinuing lines. CONSTITUTION: A shadow polygon generating section 13 generates a shadow polygon at every screening surface related to a displayed picture and a luminance discontinuing line calculating section 15 calculates a luminance discontinuing line at every light receiving surface. Since the light receiving surface is divided into several areas when the luminance discontinuing line is calculated, a luminance discontinuing line loop forming section 17 creates a luminance discontinuing line loop so as to recognize the areas. A light source state managing section 19 confirms whether or not each area is irradiated with the light from a light source and whether the formed shadow is a half shadow or full shadow (irradiation state) based on the loop. A mesh generating section 21 divides the area into meshes by using the data generated by the section 19 and a picture generating section 23 makes calculation required for the generation of a picture at every element of the divided meshes.
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公开(公告)号：JPH0636046A
公开(公告)日：1994-02-10
申请号：JP15990992
申请日：1992-06-19
Applicant: IBM
Inventor： OYAMADA KOJI , DOI AKIO , UNO SAKAE
Abstract: PURPOSE: To eliminate the need of inspecting whether the line of sight crosses boundary by selecting the constitution face of a polyhedron, which makes the boundary of and area an faces in the direction of the line of sight and executing sorting based on a distance with the eyes. CONSTITUTION: A boundary face facing in the direction of the line of sight is sorted or the boundary face facing in the opposite direction to the line of sight is stored. Picture groups on a projection face, which correspond to the boundary face, are decided by a scan conversion 3 in a sorting order. A luminance value is calculated until a system goes out a volume data area along the eyes passing through them so as to decide the value of a picture element. When the volume data area is concave, the system once enters the volume data area again after it goes out the volume data area. Similar calculation is executed on the boundary of an entering position and it is accumulated in a previous value. Thus the precise luminance value can be calculated. It is not necessary to inspect whether the line of sight crosses the boundary or not only by using the scan version 3 in a boundary face unit.
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