The second half of the previous chapter has been revised, so you can revisit it.

……

And listening to what Lu Wenjun said just now, this software was developed by this young man.

Harper and the others couldn't help but show a look of interest on their faces.

The young man did not care about the attention of everyone, calmly walked up to the front desk, turned on the projector, turned on the computer, and then said in fluent English: "Respected leaders, friends of the United States, hello everyone, my name is Yang Weining. My colleagues in the 611 Institute and the 132 Factory may be familiar with me, but my friends in the United States and the leaders of the Commission of Science, Technology and Industry are relatively unfamiliar with me, but I believe that after today's report meeting, everyone will remember me. ”

The scene in the conference room couldn't help but burst into laughter, and Yang Weining's opening remarks seemed humorous, confident and vibrant, which made everyone who was used to listening to official clichés feel refreshed.

And Harper and others feel more obvious, in this era of just opening up, Chinese in the face of highly developed Western society, there is always a sense of lack of confidence, even in the military industry.

But the young man in front of him is different, although he is also wearing a really good shirt and grass green military pants, but his spirit is different from most Chinese in this era.

Yang Weining continued: "AS THE DEVELOPER AND PATENT OWNER OF THIS AUTOCAD SOFTWARE, TODAY I WOULD LIKE TO INTRODUCE TO YOU THE RELEVANT APPLICATIONS OF THE AUTOCAD SOFTWARE DEVELOPED BY I IN THE FIELD OF INDUSTRIAL DESIGN. ”

AT THIS TIME, THE COMPUTER HAD BEEN SUCCESSFULLY STARTED, YANG WEINING CHOSE TO START THE AUTOCAD SOFTWARE, AND SOON, THE AUTOCAD PROJECTION WITH WHITE CHARACTERS ON A BLUE BACKGROUND APPEARED ON THE WHITE SCREEN.

Yang Weining clicked on the 2D drawing module and said while demonstrating: "It has been nearly 20 years since the emergence of CAD technology. As early as the sixties of the last century, 2D CAD was introduced, which was only a very simple wireframe system, which could only express basic geometric information, and could not effectively express the topological relationship between geometric data. In addition, most of the drawing with a computer is to operate the mouse to grasp the path of the line, which is very different from the feeling and effect of hand-drawing. Even if you are an artist who can easily draw all kinds of graphics, it is not easy to draw as you like with the mouse, which is an important reason why computers cannot replace manual drawing. ”

All of this was solved in 1962 with the Bézier curve proposed by the French engineer Pierre Bessel. ”

"The Bezier curve is the basic tool for computer graphics image modeling, and it is one of the most used basic lines in CAD graphics modeling. It creates and edits shapes by controlling four points on the curve: the start point, the end point, and the two intermediate points that are separated from each other. All control points and nodes on the curve can be edited, and this intelligent vector line provides engineers with an ideal tool for graphic editing and creation. ”

"It is precisely because of the Bezier curve algorithm and the development of curved surface modeling technology on this basis that Lockheed's 2D CADAM software and Dassault's CATIA software for 3D surface modeling. ”

"However, both Lockheed's CADAM and Dassault's CATIA are only capable of describing elementary analytic surfaces, and it is still very difficult to describe surfaces that change freely in complex ways on the computer, the so-called free-form surfaces. Today, the AUTOCAD software I bring to you, on the basis of Bezier curves, adds the non-uniform rational B-spline curve (NURBS) extremely correlated algorithm, and partially realizes the three-dimensional freeform surface modeling. ”

If at the beginning, Yang Weining's introduction to the history of CAD and the demonstration of 2D CAD modeling were not very eye-catching, as he shifted the topic to 3D freeform surfaces, especially when he mentioned non-uniform rational B-splines (NURBS) and solid modeling on the computer, the members of the American delegation, whether it was Hugh Robert, senior vice president of Grumman, or Edward Robert, deputy chief engineer of Boeing, were among the members of the American delegation. Williams, or Roman Rohdes, a senior engineer at Lockheed, all changed their faces.

It is important to know that NURBS and Bezier curves, which are later known as the two basic curves of CAD technology, are a very good modeling curve.

Not only can it be used to describe free curves and surfaces, but it also provides a unified expression for a variety of geometries, including conic curve surfaces, and it provides better control over the curvature of the surface than traditional mesh modeling, allowing for more realistic and vivid shapes.

It was not until 1983 that SDRC successfully applied the NURBS model to its solid modeling software, and this curve gradually spread and was widely used in the development of CAD software.

And now, it is the eve of the application of NURBS technology to CAD software, whether it is Lockheed's CADAM, or Boeing's CV, the NURBS curve is still in the research stage, who would have thought that in the southwest of China, a Chinese named Yang Weining, actually quietly applied this algorithm to the CAD software he developed.

For a moment, the faces of all the members of the US delegation became solemn.

"MR. YANG, YOU MEAN THAT NURBS CURVES ARE APPLIED TO THE AUTOCAD SOFTWARE YOU DEVELOPED?"

Boeing Deputy Chief Engineer Edward Williams was the first to ask.

Yang Weining smiled slightly and said, "This is natural, if Mr. Williams has any doubts, I can show it to you." ”

As he spoke, Yang Weining dragged the mouse, clicked on the 3D modeling function of the software, set the relevant parameters, and soon, a special 3D surface model appeared on the screen.

And as Yang Weining kept operating, more than ten minutes later, a three-dimensional model of a high-heeled shoe appeared on the screen.

Although it was only a simple black and white image model, the appearance of this virtual high heel instantly shocked all the members of the American aviation delegation.

It is important to know that now the revolution of solid modeling technology has swept the CAD industry in the West, and the mathematical model of the free curve surface established by computer calculation and processing can calculate a large number of points and other information on the curve surface, which provides the necessary prerequisites for post-processing such as CNC machining, physical property calculation, finite element analysis, etc.