VUTRAX Technical Support
VUTRAX SOFTWARE ADVICE NOTICE 116 (Issue
3) - 12 Sep 2002
Vutrax issues up to and including
PLOT - Forcing Identical
Coordinates for Photoplot & CNC Output
Note: Vutrax 12.4a onwards contain a number of
enhancements that automatically align Photoplot,
CNC DRill and CNC Milling output. This document is for
user of Vutrax 12.3b and earlier versions.
For most users the PLOT scheme for normalising the plot
near 0 0 coordinate of the plotter is the most
convenient scheme. However, different output devices use
different offsets because:-
- Plotted output needs to allow for artwork element width
and pad sizes, while CNC output is usually
required to use pad centred datums that can provide an
absolute coordinate reference for setting up.
- Plotter output formats need to force an offset to
accommodate edges of paper, tendency to lose
registration due to overshoot reaching limit switches etc.
The problem arises when these modules are used to
generate files subsequently presented to another
CAD/CAM system or viewer where the Photoplot and CNC
data will be related.
The following method can be applied to produce identical
- Select Compatible Control Files:
- Choose CNC and Photoplot output formats that operate
using the same coordinate system and
- For 0.001" resolution GERBPHOT.HXY
- For 0.0001" resolution GERBT10.HXY (or
GERB274X.HXY) & CNCBT10.NXY
- Remove Edge Clearance from the Photoplot Control File
This is a once-off change that we recommend is saved as
a new file used specially for this purpose. The
need for the offsets still applies for 'real' plots
unless precautions are taken, so you should generally use
the original file for normal use. Standard Plot control
files reside in the VUTRAX home directory (usually
The fixed offset is defined by a plot control file
where <value> needs to be zero.
e.g. If editing GERB274X.HXY to GERB274X_0_Edge.HXY
change the displayed heading at the top
(lines starting $M are displayed messages while
everything after $N is a comment) and find and change
(line 18 in this case)
$SB=1000;$N Edge clearance 5 mm
$SB=0;$N Zero edge clearance
- Suggestion: The menu system does not offer these
extension, so use Open All Files from the text
menu, and immediately Save As the
new file before applying changes.
- Prepare the Artwork to Provide a Datum
To plot a set of Artworks with consistent normalisation:
- Select Draw Box from (Edit > Boxed Items) (BOX CREATE) and
draw an outline completely
enclosing the artwork including any pads and Script at
the edge, and outside the thickness of any
boarder lines (e.g. 50 thou outside all existing drawing
on all layers).
- Type command MOVE=1 or just
M= to move to the first point of
the box. Now render it invisible
using command WIDTH 0 5 (this step
is important - placing it on an unplotted layer would
allow some types of plotting to be offset to allow for
- Make the required plots to file.
30 June 1993: Original issue.
20 Nov 1998: Revised for Vutrax 12.0 and 0.0001"
resolution Control files.
12 Sep 2002: Superceded by Enhancements in Vutrax