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Solid Edge

Reap the Advantages of a Virtual Design

15 Aug, 2004 By: Adrian Scholes

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Solid Edge automates process beginning with the product definition stage

With today's reliance on CAD systems for design, we tend to think of product design data as a mix of 2D geometry and 3D models. But most product design processes begin with a definition stage before any geometry is developed. A lead engineer may define the assembly structure, identifying major components and subsystems as a starting point. Designers might reserve parts numbers and reference other nongraphic information, such as materials, supplier names, and estimated costs. But at this point, it's all a structure -- no drawings or models exist. This is exactly why Solid Edge v16 introduces a new Zero D capability. You can define the key elements of a product's structure before you commit any geometry to paper.

Defining a Virtual Structure

Figure 1. The Solid Edge Virtual Component Structure Editor lets you quickly define major components and subsystems before committing any geometry.

A virtual structure, as the name suggests, does not require creating any physical files. You use the Structure Editor function to define the overall structure of the new assembly (figure 1). All you need to do is select a model type -- part, sheet metal, or assembly -- give it a name, and add it to the structure, repeating until you've defined all the required components. You can organize the virtual structure as necessary and quickly and easily move individual components in and out of subassemblies and reorder the tree to best suit your needs.

You can also use Property Manager to create or edit properties for any of the structure components. This lets you generate preliminary bills of materials and reports without waiting for the fully modeled 3D assembly. You can also estimate costs and other important criteria before detail work begins. The system maintains your virtual-component properties in the "real" components you create later. Defining virtual structure is an important part of the conceptual design phase of any product design.

Associating Design Data
One step further in the concept phase, a designer might lay out major components and subsystems in 2D. You create basic 2D geometry in one or more assembly sketches and use it to represent the product's primary layout. The next logical step is to assign 2D geometry to the virtual components. Right-clicking on any virtual component in the structure displays a short-cut menu. The first option in that menu is to assign or modify a virtual component's geometry. Here, you can select geometry from an assembly sketch. The system prompts you for an origin point and another point to define the x,y axis and assigns the selected geometry to that component. If multiple components are the same -- for example, four wheels -- you need to assign geometry only to the first one. This becomes the master. Choose the Position Virtual Component option from the same short-cut menu to position multiple instances using normal sketch dimensions and relationships.

Continuing on, you probably have "real" components that are useful in the concept phase and so need to position them in the 2D layout. Off-the-shelf components such as motors, shafts, and bearings are typical 3D components that designers often position relative to the 2D layout definition. Do this through a simple drag-and-drop of 3D parts while in the assembly sketch, using standard 2D dimensions and relationships between the layout and the 3D components. Alternatively, you may want to postpone the positioning of real parts in the layout and instead assign virtual components that you later replace with real parts. You can continue to assign and position any known 2D geometry to virtual components and work with the 2D layouts to validate the product structure. At this point, you still haven't created on disk any physical files for the virtual components, and you are simply reusing real components.

Creating the Hybrid 2D/3D Model
Once you complete the conceptual structure and are ready to begin more detailed design, use the Publish command to populate the structure with real part and subassembly files. Solid Edge runs through an automated process of creating each file in the structure, copying any associated 2D geometry into those files, and building the physical assembly. You can now begin to work with the geometry, using Solid Edge's 2D and 3D tools, to generate 3D components and develop the detailed 3D mockup.

As mentioned, another timesaving aspect of this approach is that you can replace virtual components with their existing 3D counterparts. In this mower (figure 2), we identified the engine assembly in the original structure, then sketched a simple rectangle to indicate the required space envelope in the layout. Once we published the assembly, we used the Replace Part command to replace the blank file with the existing engine assembly, which is correctly positioned and oriented according to the origin and axis information defined during the virtual definition.

What Works -- Made Easy
The benefits of 3D are well known, but many design processes follow a workflow that first establishes a basic product structure, using new and existing 2D layouts to create a concept, and moves to 3D only when appropriate. Solid Edge's 2D/3D hybrid design capabilities encapsulate this valuable workflow. These new Zero D capabilities mean you really can choose the right tools for the right job at the right time.

See you On the Edge next month.