Method for defining drawing planes for the design of a 3D object

A computer program product, comprising:

• a non-transitory computer-readable data-storage medium (MEM1-MEM4), storing computer-executable instructions to cause a computer system to draw a 3D object rendered in a 3D scene on a computer screen through a virtual camera;
• and
• the computer-executable instructions including instructions that configure the computer system to:
• sketch at least one first stroke (ST1) in a first plane (PL1) rendered in a first viewing frustum corresponding to a first pose of the virtual camera, said first plane (PL1) being orthogonal to a second (PL2) and a third plane (PL3);
• in response to a command of a user switching from the first pose to a second pose of the virtual camera, switch from the first viewing frustum to a second viewing frustum corresponding to the second pose of the virtual camera, said second viewing frustum being bounded by a near plane on the side of the virtual camera;
• select, as current drawing plane, a plane among the first (PL1), the second (PL2) and the third plane (PL3), whose normal has a maximum scalar product absolute value with the normal of the near plane;
• determine the extremity of a last sketched first stroke (ST1) in the first plane (PL1) which is closest to the near plane, the current drawing plane passing through said extremity, said extremity being defined as the origin (OR) of the current drawing plane;
• and
• sketch at least one second stroke (ST2) in the current drawing plane.

A non-transitory computer-readable data-storage medium (MEM1-MEM4) comprising:

• a memory area containing computer-executable instructions (EXP) to cause a computer system to draw a 3D object rendered in a 3D scene on a computer screen through a virtual camera;
• and
• the computer-executable instructions including instructions to draw the 3D object by:
• sketching at least one first stroke (ST1) in a first plane (PL1) rendered in a first viewing frustum corresponding to a first pose of the virtual camera, said first plane (PL1) being orthogonal to a second (PL2) and a third plane (PL3);
• in response to a command of a user switching from the first pose to a second pose of the virtual camera, switching from the first viewing frustum to a second viewing frustum corresponding to the second pose of the virtual camera, said second viewing frustum being bounded by a near plane on the side of the virtual camera;
• selecting, as current drawing plane, a plane among the first (PL1), the second (PL2) and the third plane (PL3), whose normal has a maximum scalar product absolute value with the normal of the near plane;
• determining the extremity of a last sketched first stroke (ST1) in the first plane (PL1) which is closest to the near plane, the current drawing plane passing through said extremity, said extremity being defined as the origin (OR) of the current drawing plane;
• and
• sketching at least one second stroke (ST2) in the current drawing plane.

A computer system comprising:

• a processor (CP) coupled to a memory (MEM1-MEM4) and a graphical user interface (KB, PD, DC, DY),
• the memory storing computer-executable instructions (EXP) to cause the computer system to draw a 3D object rendered in a 3D scene on a computer screen through a virtual camera, said drawing the 3D object being by:
• sketching at least one first stroke (ST1) in a first plane (PL1) rendered in a first viewing frustum corresponding to a first pose of the virtual camera, said first plane (PL1) being orthogonal to a second (PL2) and a third plane (PL3);
• in response to a command of a user switching from the first pose to a second pose of the virtual camera, switching from the first viewing frustum to a second viewing frustum corresponding to the second pose of the virtual camera, said second viewing frustum being bounded by a near plane on the side of the virtual camera;
• selecting, as current drawing plane, a plane among the first (PL1), the second (PL2) and the third plane (PL3), whose normal has a maximum scalar product absolute value with the normal of the near plane;
• determining the extremity of a last sketched first stroke (ST1) in the first plane (PL1) which is closest to the near plane, the current drawing plane passing through said extremity, said extremity being defined as the origin (OR) of the current drawing plane;
• and
• sketching at least one second stroke (ST2) in the current drawing plane.