Creating sheet models for drawing production

Creating Sheet models automates the creation of drawing sheets for printing of your design drawings. This process is similiar in a way to how the manual draftsperson works. Where it differs, however, is that instead of redrawing the model's geometry for each view, like the manual system requires, you simply attach views of the design model as references.

In other words, you attach as references, views of your design geometry for each plan, elevation, section, and so on. The power of this system is that any changes made to the design model then is reflected immediately in each affected view in the drawings. The electronic version of the manual drawing sheet consists of:

Sheet model— The electronic drawing sheet.
Attached models/views — References of the design geometry.

There is no hard and fast rule to how you create Sheet models, and display your drawing information from your design models. Commonly, either of two methods are used, one that scales the border to enclose the design, or the other that scales the design to fit the border.

With both methods, for 3D work in particular, it is a good idea to have separate design models and sheet models. This lets you keep the purely drawing information, such as text and dimensioning, separate from the design information. Doing this reduces the likelihood of conflicts where others, for example, wish to reference the same design model for use in a drawing of a different scale.

Scaling the drawing border to fit the design

With this method, where the drawing border is scaled up (or down) to cover the required area in the design, all text and dimensioning must be scaled the same amount, also. This is to ensure that when the scaled print is created, text and dimensioning elements are at the correct physical size.

To simplify this process, when you create a Sheet model, you have the option of associating an Annotation Scale to it, as well as a sheet layout size. Additionally, if required, you can specify the origin of the sheet layout and its rotation.

When you specify an annotation scale, the Sheet Layout element also is scaled by that amount. This is a non-printing element that shows you the outer limits of the sheet size that you choose. To this, you then can reference your own border, to which you apply the same scale factor as that for the Sheet model. Additionally, any text that you place in the Sheet model, with the Annotation Scale lock enabled, automatically will be scaled by the same amount. For example, if you are creating a 1m = 200m scale drawing, any text that you place would have to be 200 times bigger than normal so that it prints at the correct size. With Annotation Scale set to 200:1, you don't have to worry about calculating the size of the text. If you turn on the Annotation Scale lock and then select 5mm text, it will be placed in the Sheet model as 1,000mm high, but when printed at 1:200 scale it will be scaled back to 5mm high.

For occasions where you do need to place text in the Design model, a similar Annotation Scale setting is available.

Where a drawing consists of various views, and details, at differening scales, the sheet should be created at the “main” scale for the drawing. Any details, with different scales, that are then required in the drawing can be placed at a scale that is a multiple of the main scale. For example, if the main part of the drawing is 1m = 200m, or 1:200 scale, then the Sheet model is created with the Annotation Scale set to 200:1 to compensate for the scaling down during printing. If you want to include a 1m = 20m, or 1:20, detail, you would reference this detail at a ratio of 200/20 or 10:1 scale.

When you print your “drawings” you set the scale to that of the annotation scale. If the annotation scale is 200:1, you print the drawing with the scale set to 200 Design = 1 Paper (where the units are the same).

General Procedure — Creating a drawing by scaling the border to fit the design

Create a DGN file and design model, using references as required.

Create a Sheet model (this can be in the same DGN file as your design geometry, or in a separate DGN file, as required.) Set the Annotation Scale to the main scale that will be used in the drawing.

To the sheet model, reference your border file at the scale required for the drawing.

To the sheet model, reference all views of the design model that are to be at the main scale for the drawing at 1:1 (full scale). Set nesting to the level necessary to include all required sub references.

For any views that are to be at a different scale from the main scale, reference them at a scale factor of (Main Scale/Required Scale).

If necessary, use the Set Reference Presentation tool, in the References dialog box, to change the display format for the references. This applies particularly to 3D models, where the display presentation norally would be

Check that the Annotation Scale lock is enabled.

Place text and dimensions at their required size. Annotation Scale lock will scale the size of the text so that it prints at the required size.

Print the drawing at the scale required.

In the event that you need to change the scale of the drawing, you can quickly change the size of all text, by changing the Annotation Scale setting for the model.

Scaling the design to fit the drawing border

With this method, the drawing border is placed at full size and the design information is scaled up or down to fit inside the border, similar to how drawings are created with manual drafting. All text and dimensioning is placed at full size. When you create a Sheet model, you select Full Size for the Annotation Scale. Additionally, if required, you can specify the origin of the sheet layout and its rotation.

In this case, with Annotation Scale set to full size, the Sheet Layout element is placed at its real-world size (not scaled). This is a non-printing element that shows you the outer limits of the sheet size that you choose. To this you then can reference your own border, again at full size (no scale factor).

References to the design are placed at the appropriate scales as required, to fit inside the sheet/border layout. For a 1m = 200m, or 1:200 scale drawing, the design model references will be placed in the Sheet model at a scale of 1:200. Similarly, any details that are at different scales are simply referenced at the required scale. For example, a 1m = 20m, or 1:20 scale detail would be referenced at 1:20 scale. You place text in the Sheet model at exactly the size that you want in the printout. When you print your “drawings” they are printed with the scale set to full-size (1:1).

General Procedure — Creating a drawing with a 1:1 border, and scaling the design

Create a DGN file and design model, using references as required.

Create a Sheet model (this can be in the same DGN file as your design geometry, or in a separate DGN file, as required.) Set the Annotation Scale to Full Scale.

To the sheet model, reference your border file at 1:1 (full scale).

To the sheet model, reference views of the design model as required, at the scale at which each view is to be printed. Set nesting to the level necessary to include all required sub references.

Check that the Annotation Scale lock is enabled.

In the sheet model, place text and dimensions at their required size, as required for the drawing.
For dimensioning, Reference Scale must be enabled to ensure that reference units are used when dimensioning elements in a reference.

Print the drawing at 1:1 scale.

While the Annotation Scale lock really is not required in this method, because the text is placed at real-world sizes, it is good practice to have it enabled. In the event that you need to change the scale of the drawing, you can quickly change the size of all text, by changing the Annotation Scale setting for the model.