Making the lines and surfaces with unstraigth angles paralel while plotting
In AutoCAD, axis that are perpendicular to coordinate system ‘orthographic‘ axis. Our drawings are generally developed by using these axes. However, depending up on the drawing discipline, i.e. surveying, highway engineering, we have to deal with 2 or 3 dimensional non-orthogonal lines and surfaces. From time to time, we also deal with angled walls or roof surfaces in architectural discipline. Thus, in this article, I will explain how to rotate 2 dimensional lines by 0 degrees in plan and how to obtain a view from across for 3 dimensional surfaces. First of all, I will explain about the theory of the subject and then explain about a small LISP program that I prepared for you.
1) Showing 2 dimensional angled entities straigth in plan:
I will explain how to do this in MVIEW (PAPERSPACE) window, so that we can learn how to do this in plotter printouts. First of all, let’s create an angular line (blue line in Fig. 1).
Fig. 1
In the example, blue lines are our actual lines. For the first example, we need the lines in 1-2 direction. We are using the 1-3 line to aid UCS. Indeed, after the first 2 points are selected, the third point determines the direction where Y axis will be aligned with. Now, let’s continue our example where only 1-2 line is in view. At this stage, let’s move onto paper view ( LAYOUT ) and open a new MVIEW window if it was not opened yet:
Fig. 2
If we open up the window a bit smaller, then we can copy the same window under it and work on it. Later, if we make a quick double-click on the window, then the window will be activated. Here, in order to make our line parallel to the paper, what we have to do is to make the XY edge of UCS parallel to the line and go to plan view. To do this:
Command : UCS Specify origin of UCS or [Face/NAmed/OBject/Previous/View/World/X/Y/Z/ZAxis] : 3 Specify new origin point <0,0,0>: ( point 1) Specify point on positive portion of X-axis <1.0000,200.0000,0.0000>: (point 2) Specify point on positive-Y portion of the UCS XY plane <-0.2367,200.9716,0.0000>: (point 3)
When you enter UCS command, you don’t have 2 point option. The reason is that, since AutoCAD(TM) 2004, this option has become the default choice. However, AutoCAD users like us who have been using AutoCAD for a very long time, still enter this option from the keyboard. First point that we are prompted to enter is the origin point of UCS, which is the point that we marked as number 1. Second point shows the direction of X axis. And the third point shows Y axis. As soon as you select the third point, you will see that UCS symbol will be positioned parallel to you line. After this stage, we will make our line parallel to paper by using PLAN command.
Command: PLAN ( ENTER ) Enter an option [Current ucs/Ucs/World] : ( ENTER )
After that, I suggest you to take UCS back to WORLD position (I suggest that you make it a habit when using UCS) and return back to PAPERSPACE (by using PS command). Even though the operation is quite simple, it is not known by many of the AutoCAD users. Take this as a tip and let’s go back to our 3 dimensional example.
2) Taking the view angle just across for the 3 dimensional surfaces:
Fig. 3
In this example, the principle is same. However; this time, the three points that you will be marking are not on the normal plan surface that we are used to. It will be against the surface from which we would like to generate a new view. You should define the points that you will select according to the operation that you will do on UCS. If you examine our example carefully, then you will notice that X axis is parallel to the bottom surface of our imaginary wall paper, and the Y axis is parallel to the diagonal edge of our wall. At this stage, according to right hand rule, Z axis will be in exactly opposite direction of the view angle that I have drawn in red color. Later on, we will be looking at exactly in opposite direction against the wall by using PLAN command.
Now, let’s briefly explain about the LISP program that we have prepared about this topic. After copying the program under AutoCAD directory, you run the program as follows:
Command: (load “tal_vpoint.lsp”)
Parallel VPOINT command is loaded
(TAL_VPOINT or TVP) (c)1994-2007 Talia Ltd. — Erhan Toker
The name of the command that you have loaded and is ready to be used is TAL_VPOINT. You can also use TVP as alias. Let’s examine the command:
Command: TAL_VPOINT
Select a point for origin: ( Point 1 )
Select a point for X axis: (Point 2 )
Select a point for Y axis <2>: (Point 3 or ENTER for 2 dimensional)
This command simply adjusts the UCS by using the 2 or 3 number of points that you have selected. It goes into PLAN view and then takes UCS back into its original. I hope that this will be useful for you.
1) Showing 2 dimensional angled entities straigth in plan:
I will explain how to do this in MVIEW (PAPERSPACE) window, so that we can learn how to do this in plotter printouts. First of all, let’s create an angular line (blue line in Fig. 1).
Fig. 1In the example, blue lines are our actual lines. For the first example, we need the lines in 1-2 direction. We are using the 1-3 line to aid UCS. Indeed, after the first 2 points are selected, the third point determines the direction where Y axis will be aligned with. Now, let’s continue our example where only 1-2 line is in view. At this stage, let’s move onto paper view ( LAYOUT ) and open a new MVIEW window if it was not opened yet:
Fig. 2If we open up the window a bit smaller, then we can copy the same window under it and work on it. Later, if we make a quick double-click on the window, then the window will be activated. Here, in order to make our line parallel to the paper, what we have to do is to make the XY edge of UCS parallel to the line and go to plan view. To do this:
Command : UCS Specify origin of UCS or [Face/NAmed/OBject/Previous/View/World/X/Y/Z/ZAxis] : 3 Specify new origin point <0,0,0>: ( point 1) Specify point on positive portion of X-axis <1.0000,200.0000,0.0000>: (point 2) Specify point on positive-Y portion of the UCS XY plane <-0.2367,200.9716,0.0000>: (point 3)
When you enter UCS command, you don’t have 2 point option. The reason is that, since AutoCAD(TM) 2004, this option has become the default choice. However, AutoCAD users like us who have been using AutoCAD for a very long time, still enter this option from the keyboard. First point that we are prompted to enter is the origin point of UCS, which is the point that we marked as number 1. Second point shows the direction of X axis. And the third point shows Y axis. As soon as you select the third point, you will see that UCS symbol will be positioned parallel to you line. After this stage, we will make our line parallel to paper by using PLAN command.
Command: PLAN ( ENTER ) Enter an option [Current ucs/Ucs/World] : ( ENTER )
After that, I suggest you to take UCS back to WORLD position (I suggest that you make it a habit when using UCS) and return back to PAPERSPACE (by using PS command). Even though the operation is quite simple, it is not known by many of the AutoCAD users. Take this as a tip and let’s go back to our 3 dimensional example.
2) Taking the view angle just across for the 3 dimensional surfaces:
Fig. 3In this example, the principle is same. However; this time, the three points that you will be marking are not on the normal plan surface that we are used to. It will be against the surface from which we would like to generate a new view. You should define the points that you will select according to the operation that you will do on UCS. If you examine our example carefully, then you will notice that X axis is parallel to the bottom surface of our imaginary wall paper, and the Y axis is parallel to the diagonal edge of our wall. At this stage, according to right hand rule, Z axis will be in exactly opposite direction of the view angle that I have drawn in red color. Later on, we will be looking at exactly in opposite direction against the wall by using PLAN command.
Now, let’s briefly explain about the LISP program that we have prepared about this topic. After copying the program under AutoCAD directory, you run the program as follows:
Command: (load “tal_vpoint.lsp”)
Parallel VPOINT command is loaded
(TAL_VPOINT or TVP) (c)1994-2007 Talia Ltd. — Erhan Toker
The name of the command that you have loaded and is ready to be used is TAL_VPOINT. You can also use TVP as alias. Let’s examine the command:
Command: TAL_VPOINT
Select a point for origin: ( Point 1 )
Select a point for X axis: (Point 2 )
Select a point for Y axis <2>: (Point 3 or ENTER for 2 dimensional)
This command simply adjusts the UCS by using the 2 or 3 number of points that you have selected. It goes into PLAN view and then takes UCS back into its original. I hope that this will be useful for you.
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