[Chimera-users] Change map gridding for better display

[Elaine Meng]

Hi Ahmad,
If the map has a certain resolution, you cannot just increase it… that would be creating new information. To change the grid, you can only resample the original map onto the new points.  If there is no other map, you can create a new empty grid with “vop new” and then use that for resampling. 
<http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/vop.html#new>

But maybe you mean you are showing a contour surface (isosurface) and you want to make the surface look smoother.  In that case there are options to make a finer triangulation (use smaller triangles) and also to smooth the shape of the surface.  Use Volume Viewer menu “Features… Surface and Mesh options” to show all these options in the Volume Viewer dialog.
<http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/volumeviewer/volumeviewer.html#surf-options>

Or, if you are using commands, see “volume” command options: surfaceSmoothing, smoothingIterations, smoothingFactor, subdivisionLevels:
<http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/volume.html#dispsurf>

I hope this helps,
Elaine
-----
Elaine C. Meng, Ph.D.
UCSF Chimera(X) team
Department of Pharmaceutical Chemistry
University of California, San Francisco

> On Mar 24, 2019, at 3:27 AM, Ahmad Khalifa <underoath006 at gmail.com> wrote:
> 
> How can I change the gridding of my cryo-EM map to make it look better? 
> 
> I know I can resample a map in chimera on the grid of another, but I'm not sure which absolute gridding is better to view the map and how to change the gridding without a reference.