DVIEW Twist Unfortunately, in the Civil/Survey discipline, not all projects are aligned in the real world the way that we want to view them on paper. Typically, in modelspace, north is always up in the Y direction. So a road bearing N32 ° 0000'E will look like this: FIGURE 1 But when we present this on paper, we want the plot drawing to look like this: FIGURE 2 In order to get from figure 1 to figure 2, we somehow have to twist the drawing. There are essentially three ways that we can do this:. Softdesk North Rotation - Rotate the roadway entities in the master drawing. After doing this, we can also set the Softdesk North Rotation. Advantages and disadvantages of social media.
The purpose of setting the North Rotation is to essentially fake Softdesk into thinking that north is no longer up in the Y direction. It is now in a direction corresponding to the rotation of the roadway. Even though the roadway is rotated, north has been rotated as well to maintain accuracy. Dview Twist - Rotate the world coordinate system. In this case the roadway drawing entities are not rotated. The entire world is rotated.
UCS - UCS stands for user coordinate system. By default, when you start a drawing, the user coordinate system is the same as the world coordinate system, which never changes. However, you can change the user coordinate system. Using this method, the UCS can be rotated in accordance with the road. Also realize that twist is very important in relation to annotation.
Before annotating the roadway in figure 1, the user had to know how to orient the text based on the desired twist. Choosing a method of rotation should therefore take into account the ease with which text can be oriented. So what method should be used? Unfortunately, they are all fairly complicated.
Users should have a high degree of proficiency in AutoCAD before using any of these methods. Each method has its advantages and disadvantages and they are discussed next. Softdesk North Rotation Advantages a) For proper Softdesk Cogo labeling orientation and accuracy, this is the best method. Disadvantages a) Setting a north rotation other than the Y direction can be very dangerous if you forget that its set or another user does not know its set. All Softdesk defined alignments, dtms, pipes, etc. Are based on the changed north rotation.
Inconsistent data can therefore be created between users with different north rotations. B) Equating initial survey information to post-design stakeout can sometimes be difficult. C) If the user needs different orientations in different sheets or viewports, north rotation cannot help. It is only useful for one orientation. D) The same North Rotation has to be set individually for every plan drawing in the project.
Dview Twist Advantages a) The accuracy and consistency of Softdesk data will not be effected. The entire world is being rotated, so the relationship between the drawing information and the coordinate system does not change. B) Different dview twists can be set in different viewports and drawings. Disadvantages a) It can be difficult to correctly orient Softdesk cogo labels and AutoCAD text and dimensions. B) It can be difficult to set the exact desired orientation.
UCS Advantages a) It is easy to correctly orient AutoCAD text and dimensions. Disadvantages a) When the UCS is set to something other than the world coodinate system (WCS), creating and defining Softdesk alignments, dtms, pipes, etc. Will result in inaccurate and bogus Softdesk data. B) When the UCS is set to something other than the WCS, drawings that are externally referenced will be inaccurately located. C) When the UCS is set to something other than the WCS, lines and curves cannot be labeled accurately with Softdesk label commands. D) One drawing can have only one UCS. Its not possible to have different twists in different viewports using UCS.
Conclusion CMI believes that Dview Twist is the best method to use. The disadvantages of using the Softdesk north rotation or UCS rotation far outweigh any advantages of UCS / north rotation and disadvantages of dview twist.
Accuracy of data is most important and both UCS and north rotation can have a negative impact on accuracy. Expert users will sometimes use a combination of dview twist and UCS. This may be okay as long as the user understands the ramifications of using UCS and always sets the UCS back to the WCS when working in Softdesk, externally referencing a drawing, or finishing a drawing. But if a user doesnt remember to set the UCS to the WCS to do these tasks (very possible), drawing accuracy can be affected.
I received authorized training from Autodesk and learned UCS. We were in classes that were based on running Land Desk Top inside AutoCAD so it wasn't just AutoCAD. If you are working with the routines of Land Desk Top problems would result when the drawing is twisted. If you simply twist and plot (sounds like a new dance) then I don't see any difference.
So I always use UCS because of my training however UCS is always in a Paper Space view port and never in the Model Space. All work is done in the Model Space. This topic is a hardy perennial, with zealots in both camps. As a UCS devotee, I refute the notion that introducing a UCS 'harms' or 'changes' the coordinate system of the entities.
A UCS is an additional coordinate system that coexists peacefully with the WCS, and all entities retain their WCS values. Switching between UCS and WCS (or one UCS and another UCS) is simple and easy, as is writing AutoLISP routines that transparently deal with WCS values even when a UCS is in effect.
I rarely poke my head in here anymore, but SurveyorConnect is down at the moment.:). Depends on the situation. Sometimes UCS is quicker and easier. I like to use the UCSEntity routine to match a line, then do a PlanCurrent UCS to twist the screen, then change back to World UCS. Then I can use my snapcopy.lsp to make the crosshairs square with the screen.
Don't be afraid of UCS or Dview. They're both useful tools that anyone can master. I couldn't construct 3D structures in CAD for staking/checking without UCS. I have even put Carlson points on the sides of walls readable from the side but not from the top, and on the bottom of platforms readable from underneath.
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Coordinate systems typically used in Geographical Information Systems (GIS) are referred to as GIS coordinate systems. CAD coordinate systems such as UCS and WCS describe points relative to the object being modeled, not relative to a location on the surface of the Earth. GIS coordinate systems, on the other hand, describe locations on the surface of the earth. GIS coordinate systems handle significantly larger scales than CAD coordinate systems and deal with issues such as the curvature of the earth and terrain, which are insignificant to CAD coordinate systems.
Difference Between Ucs And Wcs In Autocad
There are two types of GIS coordinates systems that are commonly used. They are geographic coordinate systems and projected coordinate systems. Because the earth is not perfectly round, no single geographic coordinate system is able to accurately define all locations on the surface of the Earth.
Consequently, various organizations define local coordinate systems, where measurements are taken locally from a local datum. Local coordinate systems are considered more accurate because they align more closely with the Earth's surface in that locality, in comparison to an Earth-centric datum. Often, more than one coordinate system may cover the location you are interested in. As a general rule of thumb, the coordinate system with its datum closest to that location is considered to be the most accurate. Mapping CAD Coordinates to GIS Coordinates When you assign geographic location information to a drawing file (GEOGRAPHICLOCATION command), you also assign a projected coordinate system to the drawing. Typically CAD drawings are unitless and are drawn at 1:1 scale.
You are free to decide the linear unit a drawing unit represents. GIS systems, on the other hand, allow the coordinate system to decide the linear units. In order to map CAD coordinates to GIS coordinates, the system needs to interpret CAD drawing units in terms of linear units. The system uses the setting stored in the INSUNITS system variable as the default linear measurement of a drawing unit.
However, when you insert geographic location information, you have the option of specifying a different linear measurement (for a drawing unit).
Topics covered in this Lesson: Setting and Using the UCS When working in 3D, it sometimes necessary to change the plane that you are drawing on. For example, if you need to add some detail to the side of a wall, you would want to draw on that plane. It's like taking a sheet of paper up off the floor (WCS) and taping it onto the wall (UCS). The WCS is the World Co-ordinate System. This is the way that the default X,Y and Z axes are directed when you begin a new drawing (X to the right, Y pointing up and Z pointing towards you).
The UCS is the User Co-ordinate System. This is a ‘redirection' of the WCS based on parameters set by the AutoCAD user.
There are several ways of doing this, and we'll look at an example here. This is a simple shape drawn on the WCS with one corner located at 0,0,0. Here is the same object shown a new UCS based on the side of the object, so that you are able to draw on the side of the building - maybe to put a door in? Note the direction that the X and Y axes are now pointing.
Notice that the positive X Axis is now pointing along side of the structure. Here's how it was changed: First start the UCS command.
You first choose the 3 point option by typing 3 at the prompt. Next you have to pick three points to define the plane. The first point is the new origin.
The second point is where you want the positive X-axis to be positioned. The last point is for the positive Y-Axis. Command: UCS Current ucs name:.NO NAME. Enter an option New/Move/orthoGraphic/Prev/Restore/Save/Del/Apply/?/World: 3 Specify new origin point: Specify point on positive portion of X-axis: Specify point on positive-Y portion of the UCS XY plane: This is the ‘3-Point' option of the UCS Command.
Differentiate Between Ucs And Wcs In Autocad
It is one of the most useful, because you control exactly where the new drawing plane will be. You must also be extremely careful when picking the 3 points, or your plane can be shifted and cause some major problems.
I would recommend using this method for most of your UCS work - or at least get very comfortable with it before moving on to other methods. Make sure you are using Osnaps to select your points accurately. NOTE: Pressing enter immediately after entering the UCS command accepts the default of returning to the WCS. Here are examples of the other options of the UCS command. ORIGIN: This option moves the UCS based on a newly picked origin point.
It does not shift the drawing plane at all as you only pick one point. ORIGIN: Command: UCS Origin/ZAxis/3point/OBject/View/X/Y/Z/ Prev/Restore/Save/Del/?/: O Origin point: Z-AXIS: This choice allows you to pick two points to define the direction of the Z-axis. First you pick the new origin, then you pick a point for the positive Z-Axis. Command: UCS Origin/ZAxis/3point/OBject/View/X/Y/Z/ Prev/Restore/Save/Del/?/: ZA Origin point: Point on positive portion of Z-axis: OBJECT: Using this method, you have to pick on a 2D object that is lying on a particular drawing plane.
This gets tricky, as you have to be aware how your positive X and Y axes end up. You also need to know how the object was drawn originally as this defines its plane. Command: UCS Origin/ZAxis/3point/OBject/View/X/Y/Z/Prev/Restore/ Save/Del/?/: OB Select object to align UCS: VIEW: By choosing the view option, AutoCAD will automatically reset the UCS to be aligned with your current view, keeping the origin where it was previously located. Command: UCS Origin/ZAxis/3point/OBject/View/X/Y/Z/Prev/Restore/ Save/Del/?/: V X / Y / Z: By selecting either the X, Y or Z options, you need to first pick a point along the axis you have chosen, then provide a rotation angle based on the right hand rule mentioned earlier. This example shows how you would rotate the UCS -90 around the positive X axis.
Command: UCS Origin/ZAxis/3point/OBject/View/X/Y/Z/Prev/Restore/ Save/Del/?/: X Rotation angle about X axis: -90 PREVIOUS: This option returns you to the last setting you had for the UCS. You'll use this one a lot in 3D.
You might need to change your UCS to draw one object, then go back to what you had it set at before. Command: UCS Origin/ZAxis/3point/OBject/View/X/Y/Z/Prev/Restore/ Save/Del/?/: P Restore/Save/Del/?/: The next options are used in conjunction with each other.
You have the option of saving a particular UCS with a name. You can then restore that named UCS or delete if you no longer will be using it. Here are examples of these options: Command: UCS Origin/ZAxis/3point/OBject/View/X/Y/Z/Prev/Restore/ Save/Del/?/: S (Save a UCS Setting)?/Desired UCS name: VIEW1 Command: UCS Origin/ZAxis/3point/OBject/View/X/Y/Z/Prev/Restore/ Save/Del/?/: R (Restore a UCS setting)?/Name of UCS to restore: VIEW1 Command: UCS Origin/ZAxis/3point/OBject/View/X/Y/Z/Prev/Restore/ Save/Del/?/:? (List your UCS settings) UCS name(s) to list: Current UCS: VIEW1 Saved coordinate systems: VIEW1 Origin =, X Axis = Y Axis =, Z Axis = Origin/ZAxis/3point/OBject/View/X/Y/Z/Prev/Restore/ Save/Del/?/: D UCS name(s) to delete: VIEW1 Deleted 1 UCS name.
Rumi to jawi text converter. The function and operation of the RCS Jawi V.5 using MS Word tools that are available without changing any direction and can be used in Power Point, Publisher and others. Technical edit, copy and paste is the same as those found in Microsoft Office applications.
This was a series where a view named VIEW1 was saved, restored, listed, and then deleted. DYNAMIC UCS Another option to try is using Dynamic UCS, but I don't recommend this technique for new users.
Here it is anyway. Down on the status bar, you have an icon that turns this setting on or off. You can also toggle this on and off with the F6 key. With Dynamic UCS turned on, you can easily draw on any surface you want.
If you have a drawing like the basic building shown at the top of the page, you can draw a rectangle or box on the roof without manually setting a new UCS. The key is to look and see which face is highlighted as you move your cursor on the screen.
In the images below, you can see how this works. The left side shows the 'roof' face is highlighted and the cursor has changed to reflect the new UCS. The right shows how this looks when the right side face is active. Not the change in the colored cursor while the UCS Icon remains the same. For Further Thought: Remember when you were learning 2D AutoCAD and found that the zoom and pan tools were useful?
Now that you are dealing with a 3rd dimension, you can see how changing your USC is very useful. The more complex your model gets, the more you will use the UCS. I've seen people fight with drawing something and trying to move it into the correct position rather than just change the UCS and draw it in place to begin with. At the risk of repeating myself - you need to learn 'when' to use these tools as much as 'how' to use them.
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