Importing DWG Drawings

The Professional Edition can import a DWG file into a drawing with layers, blocks, polylines, etc. You end with a drawing much like you would if you had opened the file in any CAD program.

Once the drawing is imported, you can edit the drawing objects or convert them to survey points for stakeout.

From Drawing View, choose Tools | Import Data Into Drawing.
Choose AutoCAD DWG from the list of file types.
Choose Browse to locate the file you want to import and return to the Import dialog.
Choose Import. When TPC is done reading the file it displays ‘Finished’ in the status box. Close the Import dialog to see the imported file in the current drawing.
If you are importing the DXF file into a new drawing, untag all traverses in the Traverses Manager.
If the imported drawing is not displayed in Drawing View, choose View | Zoom | Zoom Extents.

TPC recreates the DWG file objects in the current drawing.

Importing Into a New Drawing

If you want to import the drawing as is into TPC, first create a new drawing in the Drawings Manager. You might want to create an empty drawing template and choose it, since things like the north arrow, title block and border are probably already included in the drawing you will import.

You may need to do a zoom extents more than once as TPC computes the positions of the imported objects.

Importing Into an Existing Drawing

When importing a DWG file into an existing drawing, TPC holds the current drawing extents, position and scale. Because of this, you might want to include the property boundary or portion of the right-of-way in the drawing before you import the DWG file.

Window Extents

Choose View | Window Extents to select the portion of the drawing you want to work with, then follow the command prompts on the status bar to select the diagonal corners of the extents window. TPC recomputes the scale at which the selected extents will fit on the page and centers the new drawing extents on the page. TPC may redefine either the horizontal or vertical extents in order to make the window fit the page.

Windowing the extent allows you to work with just the portion of the drawing you are interested in.

Converting Objects to Survey Points

One reason to import a drawing is to use the drawing objects in the survey. TPC can recreate coordinates for the drawing objects (end points of lines and arcs, insert points of symbols, etc). You might import a construction drawing, convert the curb lines to traverses, and then go stake them out. Or you could create survey points for all the light poles or storm drains.

Checking Construction Drawings

How many times have you started staking out a set of construction drawings only to find that things don’t match up like they should? CAD drawings often contain mistakes that show up in the construction surveying. Why? Because in CAD it’s easy to have hidden lines that aren’t the same length. It’s easy to accidentally move entities. It’s easy to do lots of things that make the data wrong but may not show up at a 1”=100’ scale.

Importing the drawing into TPC lets you check the closures, grades and inverses before you go out in the field. The result is that you catch the mistakes before the staking starts and everybody wins.

Existing Objects

When TPC imports a block from a DWG file, it first checks to see if that block is already part of the drawing. This occurs when you import a DWG file into a drawing that you are already working on. If the imported block is already part of the drawing, TPC defaults to the existing drawing block and ignores the imported block completely.

Scaling Unit Blocks

Some CAD programs assume that a block that is defined to be ‘1 unit or less wide and 1 unit or less high’ is always multiplied by the drawing scale. These blocks are called ‘Unit Blocks’ or sometimes ‘1X1’ blocks. The scale of any object that uses these blocks is always set to 1.0 since the unit block itself is multiplied by the drawing scale.

By default, if TPC reads a scale for an object that references a unit block, it forces the unit block to become a regular block and the drawing scale is not applied. The Settings Dialog allows you to change this default action with the ‘Allow Scale for Unit Blocks’ toggle.

Importing Scale Bars

Scale bar blocks are special in that they resize themselves according to the drawing scale like any unit block, but do not exactly meet the criterion of a unit block. When a scale bar is written to a DWG file, it must be written as a non-unit block. When a scale bar is imported back into an empty drawing via a DWG file, it is no longer a unit block, but it does have a block scale equal to the original drawing scale. As a result, it has the proper size when the drawing is plotted at the original scale.

You can convert the imported scale bar back into a unit block as follows:

Right click the scale bar and choose Properties.
In the block dialog, set the scale to 1.00000 and turn on Apply Drawing Scale then choose OK.

If you import a scale bar into a drawing that already has a scale bar, the imported scale bar will have its own scale and the original scale bar in the drawing will still be a unit block. The result is that the imported scale bar will be multiplied by the drawing scale twice. To correct this situation, edit the imported scale bar and set its scale to 1.00000.

Editions

Premium, Professional