Other Basic ARC+ Features
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Other Basic ARC+ Features
Line Attributes
Line types, width, and colors are used for the normal drafting conventions. Line types are also used to distinguish groups of entities. For example, wall entities may be assigned a different line color than slabs. Solids assume the same color as the polygon they were created from. Bear this in mind when choosing colors for your model.
Arcs
All arcs, whether lines, polygons or wall arcs consist of a series of short straight segments. A model containing a large number of arcs may therefore become quite large and slow down your on-screen work. The number of segments in a 3D wall arc is a variable that that you can set. For other arcs you can use a command that specifies the number of segments per arc. While working keep this value to a minimum to allow you to work fast. When your model is ready for presentation or plotting, change the number of segments for the desired effect.
Indicating
Certain commands require you to indicate a specific entity. Move the mouse until the cursor is over or close to a point on the intended entity. When you click the mouse button the system searches for the nearest entity. The entity is highlighted by changing its line attributes and the system waits for your confirmation. If you reply n (no) and do not confirm the indicated entity, the system continues to search for the next closest entity, which is then highlighted.
The Selection Group
A selection group is a group of entities and placed objects collected to enable you to perform some desired operations on the group as a whole. For example, if you are designing a building that contains several identical rooms, you can select a series of walls, windows, and doors all components of the basic room, and then copy them repeatedly in other areas of the building as required.
Layers
Layers are 3D groupings of entities and placed objects, which can be displayed or hidden. A layer can be compared to an overlay plan representing a particular subsystem of your design, e.g., electrical or plumbing layout or phases of a building. Each model can be divided into 255 layers.
Units and Scale
Entities and models are created in ARC+ in real dimensions. Thus, if you want to create a 20 cm wall, 3.30 meters high enter .2 for the wall thickness and 3.3 for its height. All entries are in meters unless otherwise stated in the command.
Scale affects only the view of the model on screen and the final output at the printer. It does not affect the model itself. The scale displayed in the status line is the scale of the screen only. If the scale is displayed as 1:100 you will find that 1 cm on the screen represents approximately 1 meter in the model. The screen scale cannot be set but is a result of your model and the viewing commands that you use.
When you plot a drawing you specify a plot scale. Since the model is created in real dimensions, a plot scale of 1:100 produces a drawing in which 1 cm on paper represents 1 real meter, etc.
For controlling the size of text at different scales you can set a reference scale when plotting drawings at different scales. This is described in the chapters on Texts and Plotting.
System Groups
roups consist of a number of entities with a logical connection between them. One type of temporary group that you are acquainted with is a selection group, which is a collection of entities that can be manipulated as a single entity.
A new type of object in the system is a system group. In certain cases you may receive a message, that the indicated entities are part of a system group.
The members of a system group are fixed. For example, a solid produced by a sculpting (Boolean) operation, or a staircase created by the stair generator are actually system groups. Each stair is an identifiable entity, however if you manipulate the stairs, the entire staircase is treated as one element. Unlike a placed entity, each entity in the group maintains its original identity. The system group is necessary to maintain certain types of data together, for example, the 2D and the 3D presentation a staircase. System groups are a feature of the system that are transparent to the user.