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Video 13 – annotative scales

  • Select one or more AutoRebar entities.
  • Run the EditScale Command.
  • Type a new value for the scale (20, 50, 100, ecc) and press Enter.
  • Possibly repeat the above operation to find the best fitting annotation scale.
Changing the scale doesn't affect the "physical" dimensions of the Rebars. Only annotations and symbols get scaled to keep the dimension of the characters uniform in the layout, regardless of the layout scale.
The Scale tab in the ArOptions dialog box can be used to specify a new scale for the entities to be drawn.


The process of scaling an annotation object goes as follows:

  1. First, decide what size that the annotations must assume on paper; for instance, we want the Marks and the bar dimensions to be printed 3mm and 2mm high respectively. Set this, or any other values in
    • ArOptions > Marks > Paper text height
    • ArOptions > Dimensions > Paper text height
  2. Set the proper units to be used in both the Model Space and the Paper Space. For instance, Meters are often used for the Model Space because it is convenient to draft the concrete structure in this unit rather than using Millimiters or Centimenters to reduce the zeros. On the other hand, Milimeters would be the obvious choice for the Paper Space in the metric system (see also the _PAGESETUP AutoCAD command to set the layout units) while Inches would for the Imperial system. Inform AutoRebar about your choice:
    • ArOptions > Units > Model units.
    • ArOptions > Units > Layout units.
  3. Prepare your drawing, possibly using different annotation scales. The annotations will assume different sizes in the model space depending on the scale used for each object. We may use the scale 1:25 for the general view of a beam, while the scale 1:10 might be more appropriate for the sections where the stirrups and the crossties usually involve smaller features.
  4. Prepare your layout using the _VIEWPORT command. In each viewport, locate the part of the structure you want to represent and run the _ZOOM αXP command, where the α parameter is defined by the following formula:
α = (MU / LU) / Scale

Where:
MU are the Model Units
LU are the Layout Units
Scale is the annotation scale used for the objects shown in the viewport.

For instance, if we were to adopt Meters and Millimeters respectively for the Model Space and the Paper Space, and create a viewport with annotation objects drawn in a 1:25 scale, we’d get:

α = (Meters / Millimeters) / 25 = 1000 / 25 = 40

while a drawing set in imperial units, with the Model Space in Feet would lead to the following:

α = (Feet / Inches) / scale = 12 / 25 = 0.48.

An arguably faster and more intuitive alternative approach makes use of the Annotative Scale drop down menu and the Edit Scale forms:

editscaleform

Here, the MU/LU ratio goes into the Paper units field, while the Drawing units fields must be filled with the Scale parameter. That establishes a direct relationship between the model and the paper space units:

MU/LU ∙ Paper units = Scale ∙ Drawing Units.

The standard Edit Scale form and the Annotative Scale drop down menu become essential tools when using AutoCAD  Annotative entities as shown for the SECTION block in the following video.