The sub-menu direction construction
Grafis works with the construction objects point and line. For the construction of these objects, the sub-menus point and direction construction are of particular significance.
The sub-menus appear not only for the tools line and point but for almost all tools for object creation or object transformation .
The direction construction is called automatically in Grafis for many functions if required by the operation. An important element of direction construction is the guide circle. The guide circle functions like a protractor. The arrow in the guide circle shows the basic direction and corresponds with the base line of the protractor. The elements of the guide circle are named in Picture 1.
Direction construction ensues in two steps:
Exactly these steps are repeated during automatic grading. As a result, the derived direction is constructed. The following applies: derived direction = basic direction + difference angle
Setting the basic direction and difference angle
| Description |
Shortcuts |
|
Fixed base direction  |
Fixed direction value in degrees |
|
Base direction from direction in base point |
The basic direction is taken exactly at the base point of the direction circle from the nearest line. |
|
Base direction from direction in pick point  |
The basic direction is set parallel to a line /curve to be clicked. |
|
Base direction from point to point  |
The basic direction is determined by the construction of two points. |
|
| Input field Difference angle | Difference angle to base direction / angle lower / angle higher |
|
|
raster |
activate raster |
|
Shortcuts direction construction
There are four construction principles for setting the basic direction:
1. Fixed direction
A fixed direction value in degrees can be entered into the field to the right of the button Fixed direction. The entry of x. g and z values for the basic direction is not permitted. Clicking the button ‚0°’, resets the basic direction to 0°
2. Direction at click point
The basic direction is set parallel to a line /curve to be clicked. The direction of the line /curve at its click position applies, taking into account the right principle. Use the <Shift> key if the beginning or end direction of a line is required. This function is active when direction construction is opened.
3. Line direction at the base point
The basic direction is taken exactly at the base point of the guide circle from the nearest line. If multiple lines are positioned in the vicinity, a prompt appears. In this case, a question mark is displayed at the cursor and the base line is to be clicked:
This function should be used imperatively when setting symbols and constructing curves to ensure that the basic direction is determined exactly where the symbol is set or the curve is attached throughout all sizes.
4. Direction from point to point
The basic direction is determined by the construction of two points. It is set parallel to the direction from the first point to the second point.
Having set the basic direction, the derived direction must be set. Initially, the derived direction in form of a long line points in the direction of the basic direction. It is altered by altering the difference angle. This process corresponds to the measuring of an angle at the aligned protractor.
The following options are available for setting the difference angle:
- Entry of the difference angle or clicking on + and - next to the entry field
or - clicking the guide circle with our without the use of raster.
The difference angle is set interactively by dragging the derived direction or by clicking the guide circle. If raster is active, the difference angle changes according to the set raster value. Entry of fixed values as well as x, g and z values for the difference angle is permitted.