The principles of 3D modelling in CAD

3D modelling in CAD (computer-aided design) is based on the use of software dedicated to the conception and design of three-dimensional models for printing. Such software offers a wide range of features and tools to enable users to bring their design ideas to life. Many sectors such as architecture and engineering now depend on this model of computer-aided design through 3D modelling, which leads to the manufacture of products. CAD enables the creation of complex models, the generation of precise data for 3D printing and offers priceless flexibility in the conception of shapes and designs. However, the choice of software, the training of users (whether beginners or professionals), and the associated costs are key elements to be taken into account to optimise productivity and the quality of model design. Three-dimensional modelling needs to meet the requirements of realistic representation and rapid screen display. To achieve this, software offers a range of modelling tools and services. Each 3D modelling software allows you to create drawings in different ways: while AutoCAD (developed by AutoDesk) is based on parametric functionalities, SketchUp focuses on intuitive and more direct modelling.

Different principles, tools and functionalities of 3D modelling on CAD software

Wireframe modelling: 3D models and design in a simplified version.

• Light data.
• Based on the points (vertices) and lines (edges) of drawings.
• Real representation of the design in space.
• Reduction in interpretation errors.
• Handling complex geometries and shapes.
• Analysis of mechanical movement.

Surface modelling: creation of smooth and complex 3D surfaces.

• Shape designer tool: representation and manipulation of the surfaces.
• Creation of complex shaped objects: bodywork, boat hull, etc.
• Treatment of hidden parts.
• Precise modelling of object intersections and surfaces to optimise design.

Solid modelling: parametric design for greater flexibility.

• High-quality modelling and engineering analysis for accurate object design: solid models are essential for engineering analyses such as stress simulation, fluid
• dynamics or thermal analysis.
• Realistic representation: the notion of material.
• Parametric design adapted to mechanical part modelling.
• Easy 3D printing from STL files.
• Complex design is made easier.

Polygonal modelling: an intuitive CAD tool.

• Used in animation, video games, computer graphics, etc.
• Intuitive, lightweight modelling for professional rendering of complex parts and smooth designs.
• Affordable price: many polygonal modelling software packages are low-cost or even free.
• Representation of part meshes: the polygonal mesh file is fla.
• Merging curves.

Curve modelling: a design method for shapes and contours of objects.

• Curve-based modelling system for generating surface geometry.
• Parametric or free modelling.
• Curves driven by mathematical equations influenced by the designer.
• Digital sculpture: tools for deforming objects (twisting, pushing, pulling).

Modelling by code: advanced customisation and automation of the
modelling process.

1. Automatically generated geometry following the designer’s parameters.
2. Excellent for 3D printing structures that can only be designed in this way.
3. Useful for parametric design, simulation and procedural generation.

Each CAD software offers its own design and modelling tools, enabling companies to choose which functionality they need. The level of training of the user, the workload required, the format of the print file, the type of parts and drawings to be designed, the design model and the functionality required should all be taken into account when choosing which software is best for you. To guide you in your choice of CAD software, here are the functionalities offered by NX from Siemens.

Advantages of 3D modelling with NX CAD

1. Assembly design
   • P○ Powerful assembly design tool: simplify design modifications and speed up system modelling with access control for parametric assemblies.
   • Designing products in their true context.
   • Identifying and managing complex problems.
   • Validation of the final design version.
      
2. Feature modelling
   • Designing fast, low-cost engineering products.
   • Unique modelling solutions: parametric wireframe modelling of surfaces and direct modelling
   • A fusion of design and 3D modelling techniques, offering users a rapid approach
      
3. Free-form design
   •  Alternative design thanks to a fusion of versatile tools for fast & easy part design: 2D, 3D, curve, surface, solid, facet and synchronous modelling.
   • Free-form modelling.
   • Interconnection with other design phases for accelerated development: simulation, manufacturing and printing.
      
4. Sketch
   • Intuitive and logic driven approach in NX
   • A new approach to drawing.
   • New features that reduce the time spent by users.
      
5. Algorithmic Modeling
   • Breakthrough capability that fuels and maximizes the ability to use a flexible, highly-intuitive, parameter-based approach to design.
   • Creating a highly-intuitive, parameter-based design
   • Parameters can be easily modified, allowing stunning initial designs to be created in a fraction of the time.

   • Better designs. Faster. With greater flexibility.

To find out more about NX CAD software, click here.