Creating complex custom lines

In order to create more complex lines it is best to take advantage of the drawing and measuring tools available within DataCAD. Before attempting a complex line type, draw a sample in DataCAD. We will create a line type to represent a picket fence.

Figure 1 shows the prototype for our fence. It will be 3'-0" high and will repeat every 6". From this sketch we can begin to figure out the basic properties for writing our line type. We will draw the line as it appears from left to right. So our 6" dimension will equal 100 units in our definition. With some simple math we can determine some relationships to help us write the definition.

If 6" = 100 units then 3'-0" = 600 units and 1" = 16.6667 units and so on. You can use interpolation to determine any distance in the sketch but the easiest way is to enlarge the sketch until the 6" dimension actually scales to 100 units in any of the DataCAD internal scales. For example if you scale the sketch so that the 6" dimension become 100 decimal feet you can then use DataCAD tools of measurement to determine all of your other stroke dimensions.

You can use the angle measurement tools within DataCAD without concern for scale. The angles will be the same regardless of scale.

Either method is fine. Just use the method that is most comfortable.

Next be sure that your line pattern is not so complicated that it will require more than 19 strokes to render. Refer to figure 2 for the sequence of points we will use to generate this line. Start at number 1 and follow the points around in order. We will need 14 strokes to enter this line definition. You could select different points and methods and still have the same exact results. For this example we have chosen to start at the top of the horizontal rail that connects the pickets. You may want to start at a point representing grade. In this case your first point would be off the sketch the distance below the picket you wish to represent grade. You would then start with a 'pen' up sequence in which no line is drawn to get to a point on the sketch where you would put the 'pen' down and continue tracing.

Whether you have a scaled drawing or are relying on math to determine the distances you should set up a chart something like this:

What we have done in this chart is set one column for the stroke designation "1-2" or "2-3" to indicate this is the stroke between points 1 & 2, etc. The next column is the number representing the angle of the stroke, and the last column is the distance. Remember that you can use negative angles such as in the "5-6" column where -90 is equal to 270 degrees. Sometimes it is easier to remember that -90 is the reverse of 90. Use the method that makes sense to you. DataCAD doesn't care if you use -90 or 270.

Once you have completed your chart simply open your DCADWIN.LIN file and write in the values along with the line name and the default spacing. In this case since 100 units = 6" we would set the default spacing to 0.6. Remember that this can be overridden by the user so it isn't critical to have this be an exact number. For this line we will allow DataCAD to adjust the line to fit since we aren't terribly worried about the exact number of pickets or their sizes. The final product of this example could be a line type definition such as:

>Picket
0.6
0.0          33.33333
90.0         33.33333
63.43495     74.5356
-63.43495    74.5356
-90.0        533.3333
180.0        66.66666
90.0         66.66666
180.0        33.33333
0.0         -33.33333
90.0         433.3333
-123.6901   -60.09252
0.0          33.33333
-95.7106    -334.9958
0.0          33.33333

Your values may differ depending on how you arrived at your angles and distances or where you start the line type definition. The final step is to fire up DataCAD and see how your line works. If you cut and paste in the example above or if you generate your own, you should have a working picket fence line for drawing those quaint little houses with white picket fences out front.