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Intergraph Smart 3D Grids

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Intergraph Smart 3D
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Grids
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Smart 3D Version
11 (2016)

You create coordinate systems by defining the reference planes and cylinders relative to the origin of that coordinate system. For a rectangular grid system, you define vertical grid planes parallel to the X (east)- and Y (north)-axes and horizontal elevation planes. For a radial grid system, you define concentric vertical cylinders, radial vertical planes passing through the center of the cylinders, and horizontal elevation planes. A coordinate system has only one reference plane or cylinder at a given position. For example, you can create only one grid plane at x = 10 ft on the coordinate system named CS-0.

Grid lines display at the intersection of the elevation planes and the vertical grid planes. Grid arcs display at the intersection of the elevation planes with the reference cylinders. You can choose which elevation planes show grid lines and arcs for a given vertical grid plane or arc.

The reference planes and cylinders associated with the given coordinate system display in the Workspace Explorer nested under the coordinate system. You can select any system as the parent of the coordinate system.The reference planes also display for graphic selection on rulers. You can turn these rulers off or on by selecting View > Rulers. The positions of the reference planes are shown as check marks on the rulers. You can drag these rulers to any position you want in the graphic window.

You can use the coordinate systems, reference planes, and the grid lines and arcs when positioning your design objects in the 3D model. Use any number of different reference grid systems for pipe racks, buildings, or other areas of the plant. If you modify the position of the reference planes and cylinders later, the software moves the associated grid lines, arcs, and all design objects whose positions depend on these reference elements.

There are two types of coordinate systems:

  • Global coordinate systems

  • Design coordinate systems, also known as local coordinate systems

Global Coordinate System

Each model contains one global coordinate system that you cannot see, edit, or delete. The global coordinate system origin is at (0,0,0) in the model. The positive Y-axis is set as global north (0 degrees) or looking port. The positive Z-axis is set as positive elevation. The positive X-axis is set as global east or looking toward the bow.

Design Coordinate System

Design coordinate systems are always created in relation to the global coordinate system. Because you cannot see the global coordinate system, you might want to create your first design coordinate system at global (0,0,0) with the Y-axis bearing set to 0 so that you can visually reference the global coordinate system.

A design coordinate system enables you to specify locations more conveniently when modeling. For example, it might be more convenient to route piping in a pipe rack with respect to the southwest corner of the pipe rack than to route piping with respect to the global coordinate system origin. This instance is especially useful if the pipe rack is located a great distance from the global coordinate system origin. Therefore, you would create a new design coordinate system with the origin corresponding to the southwest corner of the pipe rack. Then, using the pipe rack coordinate system as the active coordinate system, place the structural members of the pipe rack and route the piping through the rack. In another example, it might be more convenient to route piping in a compartment with respect to the corner of the compartment. Therefore, you would create a new design coordinate system with the origin corresponding to the corner of the compartment.

Another useful feature of design coordinate systems is the ability to rotate the design coordinate system north from the global coordinate system north. This rotation further eases placement operations if you rotate the pipe rack at an odd angle with respect to the global coordinate system.

You can also use design coordinate systems to specify a model monument. Think of the model monument as the master reference point for the model. For most models, the origin corresponds to a survey benchmark or some well-known, immovable landmark at the model site from which measurements can be made. Create a design coordinate system for your model monument instead of using the global coordinate system even if the coordinate systems are directly on top of each other. Do not define a grid system for the model monument coordinate system. The coordinate system is only used to report coordinates in drawings and reports. If you want to move the entire plant relative to the model monument, you only have to move the coordinate system representing the model monument.

Smart 3D supports the modeling of objects within a 100 km range (-50,000 meters to +50,000 meters along each axis) from the global coordinate system origin. However, due to the 32-bit precision limitations of graphic cards, objects modeled further than 10,000 meters (6.2 miles) of the global coordinate system might not display correctly when you zoom in (circular objects will appear distorted for example). If your model coordinate values are large (for example, E = 60,000, N = 55,000), to get the coordinate readout that you want, you should define a coordinate system at correspondingly large negative values (example, E = -60,000, N = -55,000). Then, use the coordinate system that you created as your active coordinate system for modeling and output. Do not bring this new coordinate system into your workspace.

The software represents each design coordinate system that you place using a triad showing the X-, Y-, and Z-axes (for Ship coordinate systems) or the north (N), east (E), and elevation (EL) axes (for Grids coordinate systems).

Elevation Planes

Elevation planes define the elevation, or height, of the grid line with respect to the origin of the coordinate system and are used in both rectangular and radial grid systems. Elevation planes are always parallel to the X-Y plane of the coordinate system.

Rectangular Grid Planes

In rectangular coordinate systems, grid planes define the grid line location with respect to the X- or Y-axis of the coordinate system. Grid planes are generally parallel to the X-Z or Y-Z plane of the coordinate system, but can be rotated (sloped) after placement. The grid line is defined by the intersection of the grid plane with the elevation plane. Optionally, you can place grid lines at all or some intersections. In general, use this command with rectangular coordinate systems.

Radial Grid Cylinders

For a radial grid system, Radial cylinders are placed by defining the location of the start cylinder with regard to a Z-axis of the coordinate system, the offset from that location, and the number of copies to generate. The spacing between the cylinder copies is equal to the defined offset. You can control the elevation planes that display a grid arc at the intersection with the cylinder. An arc is created for each quadrant of the circle rather than a circle.

Radial Grid Planes

For a radial grid system, Radial planes are placed with respect to the North \ Y-axis being 0-degrees. Radial planes are placed across the entire radial cylinder. Therefore, you cannot place a plane that is equal to or greater than 180-degrees (the 0-degree plane is the 180-degree plane, the 45-degree plane is the 135-degree plane, and so forth).