Lesson27- Creating & Using POINT



A POINT is a one dimensional object that can be used to mark special coordinates in a drawing.

  • for example, you might see POINTs with TEXT labels beside them to list elevations at various coordinates in site plans.
  • you can also snap to POINTs using the Node osnap so POINTs can be an effective construction object as well.

One way to create a POINT is to use the Point command.

  • if you invoke Point with the toolbar button you will be 
continuously prompted for points until you press <Esc>.
  • this is like picking Draw + Point + Multiple Point from the 
pulldown menu.

POINTs are displayed as a small dot by default and you may not even realize that they are there when you use this point style.

  • use the ddPtype command to select another style to display all POINTs with (in the active drawing).

When the size of points is Relative To Screen they will be the same size even when you Zoom in or Zoom out (after a Regen).

  • but you can also set the Size in Absolute (drawing) Units

Point styles are stored in the PDMODE & PDSIZE system variables

  • these variables are saved in drawings so each drawing can use unique settings for point style.

Another way to create POINTs is to use the Measure command.

  • you are prompted to select an object to measure and then you 
are prompted to enter the length of segment.
  • a POINT is placed along the selected object to mark the end of 
each segment at the specified length.
  • you can snap to these POINT objects using the Node osnap so 
 this is a practical construction technique

You could use MEASURE to help find hole centers along a construction line object

The Divide command is like Measure except you are prompted to specify the number of segments (instead of a length).

  • you would use the Divide command when it is more important that each segment is the same (arbitrary) length.
  • whereas the Measure command is used when it is more important that each segment is a specific length.

You could use DIVIDE to mark POINTs at equal distances along these contour lines in a site plan.

PRACTICE CREATING  & USING POINTs

1) Close the drawing from the previous exercise (if it is open).

2) Open the drawing T105_2.dwg in your personal folder.

This drawing is a topographical map of a site that is 1000 meters per side.
In this exercise you will create survey marker POINTS along the 100 meter elevation contour.

3) Pick Draw + Point + Multiple Point & enter the coordinates shown in the margin below to create 6 new POINT objects for the 100 m elevation contour. When you have created the final point press <Esc> to exit this endless loop.

Coordinates For 100 m Contour
790,200

570,530
760,800
630,960
140,820
250,340

The Point command is not an endless loop in itself

  • but the menu macro that invokes Point when you pick Draw +Point + Multiple Point is an auto-repeating macro.
  • you must explicitly cancel this macro by pressing <Esc>.

4) Pick Format + Point Style. Select the style shown below then pick OK.

5) Pick View + Zoom + Out.

POINTs appear to be half the size that they were before you zoomed out.

6) Pick View + Regen.

POINTs are now the same size (relative to the screen) that they were before zooming out.

At the moment the size of POINTs in this drawing is set relative to the screen size

  • so if you Zoom In or Out the POINTs will always appear to be the same size relative to your screen
  • but you may have to force a Regen to display them at their proper size (this would happen automatically when you Plot).

7) Pick Format + Point Style and select Set Size in Absolute Units and enter 100 as the Point Size. Pick OK.

8) Pick View + Zoom + In.

9) Pick View + Regen.

Now when you Zoom In the POINTs appear larger (relative to your screen size) because POINT size is in Absolute Units.

10) Pick Format + Point Style and select the (default) dot style in the upper left corner and pick OK.

You may not be able to see these dots at all right now even though the POINT size is set to a very large value.

  • if you want to work with POINTs (e.g. to snap to them) you should make them more obvious than the default dot.

MORE PRACTICE

11) Pick File + Save to update your changes to T05_2.dwg.

12) Pick File + Close to close this drawing.

13) Open the T105_3.dwg in your personal folder.

In this exercise you will first place a number of POINTs at 1.0 inch intervals along the red LWPOLYLINE.
Then you will place holes (CIRCLEs) at these locations using Node osnaps.

14) Pick Format + Point Style and select the style shown. Then pick OK.

15) Pick Draw + Point + Measure. Select the red construction line near P1. When prompted for a length enter 1.0.

When you use Measure to create POINTs along 2D objects AutoCAD starts measuring at the end where you select the object

  • the length of this LWPOLYLINE is not an exact multiple of 1 inches so there is a small segment of this object left over.
  • POINTs are exactly at 1 inch intervals along this LWPOLYLINE (which was constructed along the centerline of this linkage).

16) Right-click on OSNAP in the status bar to invoke a shortcut and select Settings to continue.

17) Select Node as a running osnap. Make sure Object Snap On is checked then pick OK.

18) Pick Draw + Circle + Center,Diameter. When AutoCAD prompts for the center move your crosshairs near the POINT at P1 to invoke a Node osnap and left-click to use that point. Then enter 0.25 as the diameter.

The size of your last CIRCLE is retained as the default so you can simply press <enter> at the diameter prompt for the next Circle.

  • this will save time when you create the remaining CIRCLEs shown on the next page.

19) Create the remaining four CIRCLEs shown below using the same technique.

20) Select the red LWPOLYLINE when no command is running and press the Delete key to Erase it.

21) Pick Format + Point Style. Select the second style (no point) and pick OK.

You used the Measure command to determine precise locations for holes in this simple component for a linkage mechanism.

  • this command generated POINT objects at fixed increments along the selected LWPOLYLINE (a construction object).
  • then you used the Node osnap to find the required CIRCLE centers to create the holes at each POINT.
  • the LWPOLYLINE object was Erased and then you changed the point style so the existing POINTs are no longer displayed.

22) Save your changes to T105_3.dwg then Close this file.

23) Open the drawing T105_4.dwg in your personal folder.

In this exercise you will create 20 new POINT objects
along the 100 meter elevation contour such that the POINTs are spaced at equal distances along this curve.

24) Pick Draw + Point + Divide. When prompted for the object to divide select the 100 m contour near P1. Then enter 20 at the prompt for the number of segments.

You could now use the Id command (Tools + Inquiry + ID Point) to find X,Y ordinates for each POINT along this contour path.

  • invoke Id and hold your crosshairs over each POINT to see coordinates in the coordinate read-out without left-clicking.
  • OSNAP must be On with a Node running osnap set and your coordinate read-out must be On as well (press F6 if it is Off)

25) Save your changes to T105_4.dwg & Close this file.

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