Scope
This paper applies to the creation of Alignment data output files from the Interactive Alignment options within MX.
Introduction
Prior to the creation of the Interactive Alignment options; Major options HALGN, HCUSP, VALGN, VERAT and VCUSP were used to generate design alignments. These were ASCII files that allowed geometry definition and when processed by MOSS (MX) they created Master and Geometry Strings.
With the evolution of interactive graphics there was a demand to be able to design alignments graphically and hence the creation of the Interactive Alignment option.
Since the creation of Interactive Alignment in 1990, users have been able to regenerate the alignments generated in Interactive Alignment by outputting an ASCII file from within Interactive Alignment. This creates a copy of the alignment in HALGN, VALGN and VERAT format to be used as a backup copy of their alignment.
How the files are written
The HALGN, VALGN and VERAT files analyze the completed alignment created in the Interactive Alignment option and then create a data file that 'best fits' the alignment by generating a fixed float, float, float scenario in the resulting data file.
Historically users have used these files as backup copies of their alignments so that they can create their entire design with a series of input files. Those users with experience of how the HALGN, VALGN and VERAT files are coded can also use them to make minor amendments to the geometry of the alignment and then re input the file to update the Master and Geometry string in MX.
Data Output accuracy
Because the data output files are a 'best fit' of the alignments generated in Interactive Alignment and they often cannot be stored to a sufficient accuracy in the data file, different iteration calculations can be made when the data output files are re-input into MX. This can lead to small discrepancies in the data between the original alignment and that generated by the data output files.
Recommendations
To create a true and accurate record of a master and geometry string created in Interactive Alignment users must make a GENIO file record of the alignment. This will store the alignment to double precision i.e. to 17 decimal places.
To enable users to do this an option to generate a GENIO file at the data output stage in Interactive Alignment will be created at MX V2.5. This GENIO data file can subsequently be input into MX with other input files to recreate the entire design. If a user wants to amend a previously created alignment this must be done with the editing tools within Interactive Alignment to maintain alignment accuracy.
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