Abstract: A computer-implemented method of drawing a polyline in a three-dimensional scene: a) draws a segment (S1) of said polyline in said three-dimensional scene, said segment having a starting point (P1) and an endpoint (P2); b) displays, in the three-dimensional scene, a graphical tool (PST) representing a set of three orthogonal planes (PLA, PLB, PLC), one of said planes being orthogonal to the segment; c) selects one of said planes; and d) draws another segment of the polyline (S2), having a starting point coinciding with the endpoint of the segment drawn in step a) and lying in the plane (PLA) selected in step c). Steps a), c) and d) are carried out based on input commands provided by a user. A computer program product, non-volatile computer-readable data-storage medium and Computer Aided Design or three-dimensional illustration authoring system carries out such a method.

Abstract: A computer-implemented method displays an assembly of digitally modeled objects in a three-dimensional scene, by the steps of: defining at least one object of the assembly as being revealable; generating a graphical representation of the assembly wherein said revealable object is located at least partially behind at least another object, called hiding object, and displaying said graphical representation; using a graphical tool selecting a region of said graphical representation of the assembly, called a revealing zone; and rendering a three-dimensional scene comprising a three-dimensional representation of the assembly wherein a portion of the revealable object located behind the hiding object and comprised within the revealing zone is shown by transparency through said hiding object. A computer program product, a non-volatile computer-readable data-storage medium and a Computer Aided Design system for carrying out such a method.

Abstract: A computer-implemented method of drawing a polyline in a three-dimensional scene: a) draws a segment (S1) of said polyline in said three-dimensional scene, said segment having a starting point (P1) and an endpoint (P2); b) displays, in the three-dimensional scene, a graphical tool (PST) representing a set of three orthogonal planes (PLA, PLB, PLC), one of said planes being orthogonal to the segment; c) selects one of said planes; and d) draws another segment of the polyline (S2), having a starting point coinciding with the endpoint of the segment drawn in step a) and lying in the plane (PLA) selected in step c). Steps a), c) and d) are carried out based on input commands provided by a user. A computer program product, non-volatile computer-readable data-storage medium and Computer Aided Design or three-dimensional illustration authoring system carries out such a method.

Abstract: A computer-implemented method displays an assembly of digitally modeled objects in a three-dimensional scene, by the steps of: defining at least one object of the assembly as being revealable; generating a graphical representation of the assembly wherein said revealable object is located at least partially behind at least another object, called hiding object, and displaying said graphical representation; using a graphical tool selecting a region of said graphical representation of the assembly, called a revealing zone; and rendering a three-dimensional scene comprising a three-dimensional representation of the assembly wherein a portion of the revealable object located behind the hiding object and comprised within the revealing zone is shown by transparency through said hiding object. A computer program product, a non-volatile computer-readable data-storage medium and a Computer Aided Design system for carrying out such a method.