How to ensure grid cells to stay rather than refresh in RVIZ?

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Hi all. I have finally took a step in my elevation map project, that is to show grid columns (elevated cells) from the camera depth images. Picture: elevated cells height.png

However, whenever I shift the camera to different angles, the grid columns doesn't save but instead, refresh to fit the new depth images. Is there solution for this so that I can save the grids and create a map with elevated walls?

Thank you!