Mechanical Desktop Training

Introduction to Mechanical Desktop 4

 1 Surface Modeling Tool
 2 Parametric Solid Modeling Tool
 3 Assembly Modeling Tool
 4 Associative Drafting Tool
 5 Key Points

Aims and Objectives
The aim of this tutorial is to introduce the four major design tools of Mechanical Desktop. After studying this tutorial, you should be able to describe the four major design tools of Mechanical Desktop.

Overview
Mechanical Desktop is a computer-aided design application for making 3D Non-Uniform Rational B-Spline (NURBS) surface models, 3D parametric solid models, assemblies and sub-assemblies of solid models, and associative engineering documents of 3D surfaces, solids, and assemblies. It has four sets of design tools: Surface modeling, part modeling, assembly modeling, and associative drafting. Because Mechanical Desktop runs on top of AutoCAD, all the design and drafting tools of AutoCAD are available. See Figure 1.

 
Figure 1  Four sets of Mechanical Desktop design tools together with AutoCAD tools

Surface Modeling Tool
The surface modeling tool of Mechanical Desktop is a Non-Uniform Rational B-Spline (NURBS) surface modeling system for design and manufacturing. You can use it to construct free-form surfaces in a computer. In addition, you can use its supplementary tools to construct and edit wires for constructing and editing NURBS surfaces. Apart from making surface models, you can use a NURBS surface to cut an AutoCAD native solid or a Mechanical Desktop parametric solid. Working in the opposite direction, you can convert an AutoCAD native solid or a Mechanical Desktop solid to become a set of NURBS surfaces. Figure 2 shows the surface model of a scale model car.

Figure 2  Surface model

Parametric Solid Modeling Tool
The part modeling tool is a parametric feature-based solid modeling system for constructing, and subsequent editing, of a dimension-driven 3D solid model. Solids are constructed from rough sketches and can be modified. Surfaces can be included. Besides, you can convert a parametric solid to a set of surfaces, convert a parametric solid to a native solid, and convert a native solid to a static parametric solid upon which you can add parametric solid features. Figure 3 shows a parametric solid model.

 
Figure 3  Parametric solid

Assembly Modeling Tool
The assembly modeling tool is a design tool for assembling a set of solid parts to form assemblies and sub-assemblies. Assembly modeling involves the application of constraints to selected pairs of features of the solid parts. With an assembly, you can check interference and set up a number of assembly scenes in which you can explode the solid parts. Figure 4 shows the assembly of a scale model car.

 
Figure 4  Assembly

Associative Drafting Tool
The associative drafting tool is used for generating 2D engineering drawing from 3D objects, surfaces, parametric solids, and assemblies. You can construct orthographic, isometric, auxiliary, detailed, and broken drawing views. The engineering drawing and the 3D solid parts are associated with each other. Changes in either the engineering drawing or the 3D solids cause automatic changes in the other part. Figure 5 shows the associative engineering drawing of a car assembly.

 
Figure 5  Associative engineering drawing

Key Points
Mechanical Desktop is an engineering design tool that runs on top of AutoCAD 2000. It has four powerful design tools: surface modeling tool, parametric solid modeling tool, assembly modeling tool, and associative engineering drawing construction tool. Basically, the application window is much the same as that of AutoCAD 2000 with a few differences. It has additional pull-menu items. It has a Desktop Browser that provides command shortcuts. AutoCAD pull-down menu items are rearranged.

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