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Productivity Corner: MicroStation's 3D Capabilities, Part 2

14 Feb, 2005 By: James Dyer Cadalyst

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More tips for creating, editing and viewing 3D models

This month's Productivity Corner column is the second part of our two-part series, focusing on some of MicroStation's 3D concepts and functions. (If you missed Part 1, click here to read it now.)

3D Views and View Control
When working in a 2D model, you are viewing the design plane from above. The 2D view control tools allow you to move around your design in a manner consistent with working on a sheet of paper.

When working within a 3D model, you will be viewing the design from any direction. Tools in the MicroStation View Control tool box (figure 1) allow you to rotate a given view to any orientation, or you can specify a camera target and eye point position. To accelerate the setup, MicroStation has eight standard views you can use: top, front, right, isometric, bottom, back, left, and right isometric. You can rotate the view in any direction or add perspective. The view names describe the orientation of the design cube in the view, relative to the viewer.

Drawing in 3D
As discussed last month, MicroStation by default will place data points within a 3D model at the view's active depth. At the location where you snap a tentative point or place a data point in a blank part of a view, it will be located at the active depth. However, you can snap a tentative point to an existing element, within the model, at any depth in a view. In such a case, when you accept such

Figure 2. The 3D Main tool box.

tentative points, the data point is placed at the level of the snap point.

3D Tool Boxes
MicroStation's standard 3D construction and modification tools are contained in the following tool boxes: 3D Main tool box (figure 2). This can be launched by navigating to the Tools / 3D Main / 3D Main pull-down menu. The 3D Main tool box contains tool boxes for constructing and modifying solid models.

Figure 3. MicroStation 3D tools: 3D Primitives, 3D Modify, 3D Construct and 3D Utility.

All of the Toolboxes are launched from the 3D Main Toolbox. MicroStation 3D tools are compartmentalized into four sub Toolboxes for 3D primitives, primitives, construction and utilities (figure 3).

In addition to the 3D solids functions found within the 3D Main tool box, MicroStation has advanced solids modeling construction and modification tools contained in the Feature Modeling tool boxes. Feature Modeling functions will be covered in future articles.

Using AccuDraw in 3D
When working in 3D, your life is much simpler when you effectively use AccuDraw. As you are designing in 3D, AccuDraw is an intelligent drawing assistant that will interpret the position of your cursor relative to previous data points, view orientation, or coordinate system. With AccuDraw you can also enter additional data points that may be based on those placed previously.

AccuDraw was designed to work within the 2D and 3D drawing environments. In MicroStation you can use AccuDraw in views other than the orthogonal views, such as top, front, right and so on. Using 3D rotated views such as isometric or right isometric will make it much easier to visualize your design. And, AccuDraw shortcuts allow the alignment of the drawing plane to the current view, or to orthogonal top, front or side views. Meaning, regardless of the view you are working in, AccuDraw allows you to place elements that are aligned to the orthogonal views.

Designing in 3D: The Fundamentals
3D design, manipulation and visualization are wide topics to cover. Let's transition from the 3D design environment, views and view manipulations to an introduction to the fundamentals of constructing 3D models.

When placing elements in a 3D file, the elements are placed, by default, parallel to the view being used. When you use AccuDraw, they are placed in the AccuDraw drawing plane. When drawing in 3D, you will use AccuDraw in a similar fashion to working in 2D. Meaning, AccuDraw will default to the plane of the view currently active.

MicroStation DGN files are created from 3D seed files. My recommendation is to use the 3D seed file SEED3D.DGN delivered with MicroStation. The MicroStation ACS triad will appear in each view. The triad will be placed at the coordinate location equal to x,y,z=0,0,0, displaying the directions of all axes. Of course, you can enable or disable the display of the ACS triad by selecting the View Attributes dialog box from the Settings / View Attributes pull-down menu.

When constructing 3D geometry you will see that placing elements in 3D is no more difficult than in 2D. And MicroStation's views help you correctly orient the elements.

Basic Element Manipulation in 3D
One of the great aspects of MicroStation is that all the 2D element manipulation tools you use every day also can be used when working in 3D. Elements can be moved and copied without changing their orientation, meaning that vertical elements will remain vertical and horizontal elements will remain horizontal. Extra caution should be exercised when rotating elements: In 3D, the elements are rotated about the z-axis for the view.

MicroStation's Auxiliary Coordinate Systems
As previously discussed, the default coordinate system of MicroStation is the rectangular, or Cartesian, system (figure 4). Additionally, MicroStation has two other coordinate systems available to you: spherical and cylindrical.

You can use the spherical coordinate system (figure 5) to draw objects that have a spherical nature, such as geodesic domes or cylinder heads. With the spherical coordinate system, locations are specified by two angles and a distance from the origin of the coordinate system.

In a similar way, the cylindrical coordinate system (figure 6) simplifies the location of points on cylindrical objects, such as a spiral staircase or a screw. In this system, locations are specified by the distance from the origin, an angle and the height on the z-axis.

As you will see next time, you can use AccuDraw shortcuts to create a rectangular ACS (Auxiliary Coordinate System). Note that you cannot use AccuDraw to create a cylindrical nor a spherical ACS.

MicroStation's 3D tools allow you to work on a single 3D model, rather than separate 2D models. When your 3D modeling is complete, working drawings such as plans, elevations, sections and details are generated from the single model. Any required modifications are made to the model just once, then the drawings are regenerated.

Additionally, MicroStation's rendering and visualizing tools allow you to produce realistic color images of your design model.

MicroStation's 3D creation, editing and viewing tools are both easy to use and powerful. We will explore more of the concepts and power related to designing 3D solid and surface models with MicroStation in subsequent columns.

Until next time - enjoy MicroStation!

Cadalyst's MicroStation tips included in "Productivity Corner" are compiled by James Dyer and were tested using MicroStation V8 2004 Edition. Cadalyst welcomes MicroStation tips: E-mail them to james.dyer@bentley.com. By submitting a tip or code, you grant Cadalyst magazine the right to print and distribute your tip or code in print, digitally and by other means. Cadalyst magazine and the authors retain the rights to the tip or code, which are not to be downloaded or copied for commercial use.