If you are using OrCAD to design your circuit, you may find that when the Gerbers are generated and loaded into the V-One software, the scaling is incorrect. Usually the circuit shown will be absurdly large. For example:
Why does this happen?
When a Gerber file is generated, the design software will indicate the units used (Imperial or Metric) directly in the Gerber file. The initial lines of a correctly formatted Gerber file is shown below:
In the snippet above, line 3 indicates the units used.
%MOMM*% - Specifies the XY coordinates are in Millimeters
%MOIN*% - Specified the XY coordinates are in Inches.
Notice how each Gerber command is in a new line. In contrast, when OrCAD generates Gerber files, the units command is not in a dedicated line. As shown in line 3 below.
This subtle change is unexpected and our software ultimately discards the command. As a result it assumes the XY coordinates are in inches instead of millimeters, resulting in the scaling mismatch.
How to fix this?
To resolve this is straightforward, there are two options:
1. Set your export units to Imperial.
Our Gerber parser assumes coordinates are in inches by default. In OrCAD, if you set your export units as inches, then the file should load as expected.
2. Manually tweak the file.
Manually open up the Gerber file with a text editor, and edit the file so that the %MOMM*% command is in a new line.
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