Lesson 7-3. Tracing raster symbols
Brief
description: During
this lesson you will learn how to trace raster symbols.
 For detailed information on these subject see Working with raster symbols section of the Quick Start guide.
Using the Open
command from the File menu load the AutoCAD Trace_3.dwg document from the Lesson_7
folder.
| Raster symbols are recognized in accordance with patterns stored
in special template libraries. To recognise a raster symbol, you need
to create the corresponding vector template. This can be done using
vectorization, tracing, or simply by drawing vector objects over the
raster symbol. |
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In this example, vector templates have already been created
with automatic vectorization. Vector objects are grouped in blocks.
Training the program to recognize symbols
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Select the first vector block.
Run the Train Symbol command from the rConvert menu.
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Press the Create Symbol from selection 
button - the new symbol will appear in the Train
Symbol dialog.
Press the Save As 
button of the Train Symbol dialog.
Save the template with the name - tech_1.
INFORMATION:
By default, templates are stored in the Shapes folder. To save new symbols,
you can create a new subfolder with the name - Technology, for example.
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Choose Create in the AutoCAD command line (do not
close the Train
Symbol dialog).
Select the next vector symbol.
Press Enter
to complete the selection command - the second selected symbol will
appear in the Train Symbol dialog.
IMPORTANT!
Specify the connection lines for this symbol using the Select connection lines button
 . (Connection
lines are the lines of variable length, with which a symbol is connected
to other objects).
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Press the Save As
button of the Train Symbol dialog.
Save the template with the name - tech_2.
Repeat the same actions to train the program to recognize all
other vector blocks, assigning them the names tech_3, tech_4
Remember to specify any connection lines!
Close the Train
Symbol dialog.
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Tuning tracing parameters & tracing
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Choose Conversion
Options from the rConvert menu.
In the Recognition tab of the R2V Conversion Options dialog select
the checkbox next to Symbols.
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Open the Symbols tab of the R2V Conversion Options dialog.
Select the checkbox next to the newly created group of symbols
- Technology, or for each individual
symbol which is presented in the scheme.
Choose Strategy - Standard.
Set the Accuracy slider to the Low position.
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Select the Fixed Scale checkbox; set the scale equal to '1'
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Choose the orientation - Horizontal and Vertical.
Press OK.
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Open the Raster To Vector toolbar.
Choose a tracing mode - for example, Make Vector
and Keep Raster by pressing the button Make Vector and Keep Raster, and the tracing command - Trace Symbol.
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Click once on each scheme unit on the raster image.
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