Linework. Drew rectangle with three points

[WilliamMaestre]

Good afternoon,

I'd like to be able to draw a rectangle (a manhole cover or a gully, for example) using three points. The first two points would be one side and the third one would be one point on the opposite side of the rectangle. I'm trying the rectangle code set in the Linework but it doesnt fo what I need. What worries me is that both sides of the rectangle dont have to be of the same elevation. I want to avoid to survey the four corners of evry manhole.

Regards

[Asmir]

Try using feature line

[m_kingdon]

I am not very knowledgeable on linework. But you might be able to design a dynamic block that is based on a rectangle with parameters (such as scale, perpendicular, basepoint and rotation) that would allow you to place a rectangle with only a few clicks.

[ChrisRS]

I do not see a Civil 3D-specific solution to your issue.

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On to your question:

• Mathematically, an infinite number of rectangles pass through three points. We do not care about them.
• There are only three rectangles that pass through three points such that two of the points are vertices of the rectangle. 
• The AutoCAD RECTANGLE command quickly constructs these three rectangles.
  You need to make use of the Rotation option.   
• Process:
  1. Type RECTANGLE.
  2. Select one of the three points.
  3. Look at the command line.
     Select or type R for Rotation.
     
  4. Click on the second point. This establishes the baseline rotation.
  5. Click on the third point. The rectangle is drawn.
     
  6. You may want to adjust the rectangle manually. 
  7. NOTE:
     The command line is your friend; when you start the RECTANGLE command, it shows:
     RECTANGLE: Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]:
     C, E, F, T, or W will allow the user to specify Chamfer distance, polyline elevation, fillet radius, extrusion thickness, or polyline width.

I hope this helps.

[Pointdump]

Hi William,
I see what you're trying to do. Your 3rd shot won't be a perfect right angle from the first 2 shots, so the problem is how to automatically produce a trapezoid.(At least one pair of parallel sides.) Take the 4th shot.
Dave

[WilliamMaestre · Accepted solution]

Good morning,

Thanks everyone for your answers. At the end I created a macro in Excel. The macro uses the first two points (vertex of the rectangle) and creates a parallel using the third surveyed point. It also calculates the level of the two new vertexes.

The macro changes the codes of the four points (the original two vertexes and the newly calculated ones) to allow C3D to use its Linework Codes.

The plan is to do the same in Lisp but I need time to dive in it. This will avoid us some extra steps (like open excel and launch the macro).

Regards

[rl_jackson]

I never saw this, @WilliamMaestre but you can create a rectangle using the Survey Database import using the RECT command or as in my case for field ease I've change this to R3. This function basically, creates the closing "4th corner" and closes the figure. Also, which is a little nicer is the ability to to create a rectangle from just 2 field data points. This function works similar to the Horizontal and Vertical Offset feature where the syntax would be RECT-2.0 for left or RECT2.0 for right on the last point shot.

[cstpierre]

Hi,

Can you tell me how to use the RECT linework code in a FBK file for 3 measured points (two corners and one on the opposite side)?

The following draws a trapezoid:

F1 VA 2002 100.00000 40.000 90.00000 "BUILDING1 B"
F1 VA 2003 94.59588 80.000 89.59590 "BUILDING1 C"
F1 VA 2004 130.00000 75.000 89.59597 "BUILDING1 RECT"

And this one draws nothing:

F1 VA 2002 100.00000 40.000 90.00000 "BUILDING1 RECT"
F1 VA 2003 94.59588 80.000 89.59590 "BUILDING1 RECT"
F1 VA 2004 130.00000 75.000 89.59597 "BUILDING1 RECT"

Claude

Leica Geosystems

[rl_jackson]

The first one is the correct method of coding the rectangle, however this will look trapezoidal if the data isn't at a true 90 degrees or close to 90 degrees. I have found that using 2 point with the offset distance easier to establish the rectangle. The would be a begin code for the first point and then the second point would include the RECT -2.0 or 2.0 depending on if it's to the left or right.