We keep hearing that 3D modelling and intelligent objects are the future of building design. Can AutoCAD Architectural Desktop Release 2 smooth the transition to the new era?
Autodesk’s AutoCAD Architectural Desktop Release 2, or ADT2, uses intelligent software objects to make the design process more productive. It is based on creating a building model rather than the more traditional CAD approach of using lines and arcs to create a set of drawings. The model is assembled using these software objects, which are representations of real objects such as walls, doors and windows.

The idea of ADT2 is to develop and maintain a single model from which all of the design drawing data is extracted, so the building developed in the initial design phases is used in the development process through to facilities management and decommissioning. The software supports the Industry Foundation Classes 5.1-based project model data exchange as defined by the International Alliance for Interoperability.

ADT2 combines conceptual design, design development and construction documentation. The first allows the designer to build a basic shape and then put in the floor levels. The design stage is where all the finer details, such as walls and doors, are added. The construction documentation stage is when the whole model becomes plans that the contractor can turn into a finished product.

The first and third stages work well. The conceptual design allows the architect to create a model of the building using geometrical shapes. Shapes can be added together, subtracted or intersected. For example, if you have a cylindrical shape and need to create a recess in it, a rectangle can be subtracted from the cylinder to create the recess. Once the conceptual shape is arrived at, the architect can subdivide the conceptual elements into floor levels before going on to the more detailed design stage.

Throughout this process, the shapes and resultant model can be manipulated or changed at any time. Where groups are formed, they can be viewed in model explorer, which has a tree-like structure on the left-hand side. Here, other drawings or parts of drawings can be dragged and dropped into the project and all changes are updated and added to the model.

ADT2 also offers handy operations to ease the construction documentation phase. This is where the architect annotates and adds dimensions to the drawings to produce the finished article. The architectural scheduling facility is particularly useful. In the case of a door, information is requested on its type, glazing, fire rating, material and finish, as well as its physical dimensions. The information is displayed in a schedule table. This is tracked and automatically updated whenever a change is made to the object.

It is the design stage between concept and construction documentation that is disappointing. The ADT2 design stage menu contains the main objects required to assemble a building: columns, walls, windows, doors and stairs. These contain 2D and 3D data along with the intelligence to understand the object’s physical properties, such as size and type. They can also relate to other objects, so a door will recognise if it clashes with a column.

To create a new door variation, you pull down the design menu and choose door, and then styles. You name it and then edit it to your requirements from a series of templates. When you add it to the model, you put in the dimensions. Doors and windows work fine

but the wall category was more difficult. It was not so easy to create a new style for a double-line wall object.

These objects are key to developing the building model. With ADT2, you need to read the manual carefully to get to grips with some of the object styles, such as walls. Creating a wall without consulting the manual is difficult.

Then there is the problem of seeing close-up details on objects. Autodesk has introduced an overly complicated solution to the problem of showing object details in plan, section and elevation at different scales. An object, say a window, needs to display different levels of graphical information at different scales. But the objects are not sophisticated enough to show sill and frame detail when used in a large scale. To address this, Autodesk has introduced a solution, called display reps, which automatically calls in separately drawn graphics showing the correct detail on an object. This turns out to be a fiddly operation.

At any stage, the model can be exported to 3D Studio Viz for visualisation and animation, to create walk-throughs. This remains a dynamic link, so any changes made in the model within ADT will be automatically reflected in Viz. But beware: the privilege of using Viz will cost an additional £1500.

But it is early days for such software. For most users, the transition from lines and arcs to assembling a building using 3D intelligent objects will be a steep learning curve, and many will need some form of training. But the longer-term benefits to be gained will compensate for the extra expense on training and getting used to the ADT2 system.

David Clarke of Autodesk replies

We have never had a problem with building a library of objects. The styles section in the design menu means you can build an enormous variety of components from one basic object. There are 600 objects in the package and you can create an infinite number of styles to go with them. Other reviewers have found the styles feature useful, and we are constantly updating the objects as more are released. Three-dimensional object modelling is a new way of working. We do not want to dictate to people how they use the software. To cope with that, we are constantly looking at how to improve the product so that we can adapt it to the way it is used in practice. Something like the display reps could be changed if users found it too fiddly. We are holding focus groups and user groups to see how people work with the whole package. The flow of commands that are set up now could be adjusted to suit users’ needs in the future. David Clarke is Autodesk’s business development manager for construction

What it costs

AutoCAD Architectural Desktop 2 costs about £3600. Upgrade pricing for AutoCAD Architectural Desktop Release 1 users is £495, and for users of AutoCAD Release 12 it starts at £595. More information can be found at www.autodesk.com/archdesktop.


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