Positioning Control

There are four ways of setting the position attribute:

• Explicitly

• Relatively

• Using Ship References

• Using the Model Editor

1. Selecting Position > Explicitly (AT) will display the following two forms.

   

   The first is the Positioning Control form. By default this appears at the top right on the main menu bar but can be dragged to any position on the screen.

   The Positioning Control Form (event-driven graphics) is shown automatically whenever you need to pick positions in event-driven graphics mode. It lets you specify how your cursor picks are to be interpreted as positions.

   The Working Plane toggle provides a quick way of activating or deactivating the working plane. If set to On, all picked positions will be projected onto the current working plane.

   

   The form has two option lists from which you can make the required selections.

   

   Pick Type option lets you control the types of items to which cursor picking will respond. As you move the cursor over the 3D View, only items of the specified type will be highlighted as the cursor passes over them. The identities of highlighted elements are shown in the prompt bar, immediately above the graphical view.

   The choices are:

   Any	You can pick any element, aid, Pline or Ppoint.
   Element	Picking is restricted to elements.
   Aid	Picking is restricted to drawing aids.
   Pline	Picking is restricted to structural Plines.
   Ppoint	Picking is restricted to Ppoints.
   Screen	Lets you pick anywhere in the graphical view, which identifies two co-ordinates. The third co-ordinate is taken from the current Working Plane.
   Graphics	Lets you pick any graphical element (including aids, construction pins, ) that is displayed in the view.
   External

   

   The Pick Method option determines how the position will be derived from subsequent cursor picks. The currently selected mode is shown in the prompt bar.

   Note: Most of these options are mainly applicable to Steelwork.

   The choices are:

   Snap	Selects the snap point nearest to the cursor pick point.

   

   Distance

   Applies the offset value, which you enter in the adjacent text-box (for example, 500 gives a point 500 mm from the nearest snap point, measured towards the cursor position; –500 gives a point 500 mm from the nearest snap point, measured away from the cursor position).

   

   Mid-Point

   Derives the mid-point between two snap points along a linear item

   

   Fraction

   Subdivides the distance between two snap points into a specified number of parts (as entered in the adjacent text-box). Then derives the fractional position closest to the cursor pick (for example, 6 gives a point at the nearest sixth of the distance along the line joining the first snap point to the second snap point).

   

   Note: The length of the picked item is subdivided into equal parts (6 in this example), each of which behaves as a snap length in its own right. Thus the derived position is at the nearest integral fraction to the picked position.

   Proportion

   Derives the point whose proportional position between two snap points has been entered in the adjacent text-box (for example, 0.25 gives a point 25% along the line joining the first snap point to the second snap point).

   

   Note: The value is expressed here as a proportion of the distance from start to end.

   Intersect

   Lets you pick two lines (any directional items) or three planes and then it derives their intersection point.

   

   Note: Linear items picked here do not intersect. Derived position is at projected intersection of second picked item onto first picked item, so order of picking is significant.

   Cursor

   Places the derived point exactly where the cursor picks on the element.

   

   The Position At form lets you position an element either by typing in co-ordinates or by reference to the position of another design item.

   Use of the Datum option allows identification of the specific point on the element to which the position is to apply, or to a Designate Position.

2. If Designate Position is selected then you will be prompted to pick the position on the element using any of the facilities provided by the Positioning Control form.

3. To define a position explicitly, enter the required co-ordinates in the boxes, using the scrollable lists to set the appropriate direction in each case.

4. If necessary, use the, WRT (with respect to) box to identify the element whose co-ordinate system is to be used for the Position data.

5. To define a position by reference to existing design items, use the Positioning Control form and the cursor to identify the required positions by picking them in a graphical view.

6. If required, the Lock options can be used to fix the current co-ordinate along any axis.

7. To position another element, use the Select drop-down menu options to change the focus of the form.

8. Use the CE or Owner option if you have already navigated to the required item, or use the Pick or Pick Owner option and then pick the required item when prompted.

   

   The form will display the current position and you can then change any part of this by entering new values. The position you give will be relative to the Datum, which may be the Origin or a selected ID Design point.

   The Explicit Position option lets you bypass any graphical picking operation by entering an explicit position.

9. Click Explicit Position to display an Explicit Position form.

10. Click Explicit Position to display the Ship Position window.

11. Right-click over Format, and then select Format XYZ.

    

12. Selecting Position > Using Ships References will display the following menu:

    

    The Position - Ship Reference form is a tracking form, which means when you navigate to an element, the form automatically updates itself to the current database’s element, showing its position both in terms of the ships reference system and absolute position X, Y, and Z.

13. Selecting Position > Relatively (BY) will display the following menu, as well as the Position Control menu described earlier

    

    The values you give will position the item by that amount relative to its origin.