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OVITO => Support Forum => Topic started by: mathewni on January 21, 2019, 07:42:54 PM

Title: Unwrapping dislocation segments in the CA file
Post by: mathewni on January 21, 2019, 07:42:54 PM
Hello, I am trying to understand how OVITO calculates the wrapped coordinates of dislocation segments printed in the CA file. In some configurations, I notice that the coordinates of the segments can be outside the box boundaries one can calculate using the SIMULATION_CELL_ORIGIN and the h-matrix (SIMULATION_CELL_MATRIX). Isn't the CA file always supposed to show the wrapped coordinates of the dislocation segments?
Title: Re: Unwrapping dislocation segments in the CA file
Post by: Alexander Stukowski on January 22, 2019, 09:50:44 AM
Hi,

The CA storage format reflects how the dislocation lines are represented in memory by Ovito: A single dislocation is always represented as one continuous line, which doesn't wrap back into the simulation box. The first vertex of the line is typically located inside the simulation box, but the other vertices of the line may be located outside of the box if it crosses a periodic box boundary.

When Ovito renders the dislocation lines in the viewports, it folds them back into the simulation box on the fly and splits segments when necessary. If you are interested in this "wrapped" representation of the dislocation lines, you should export the dislocation data to the "VTK Dislocation Lines" file format instead of the CA format.

-Alex