Hi Daniel, You can use a Chimera marker file but that only knows how to place spheres. If you wanted to make use of the "map" and "matrix" attributes you added to the markers then that would require some extra Python script. That could be done -- it is just a different format of input from the script I sent you. If you can't display hundreds of copies of the map due to slow graphics then it doesn't matter how you input the data. Having hundreds of copies of the same map open doesn't load the map data more than once. So you shouldn't run out of memory. But the surface for each map might have a million triangles and it does make a separate surface copy for each copy you place in your tomogram. Of course you won't see the detail in a tiny map put into a tomogram so the solution would be to display a very coarse image of the map that is being placed many times in the tomogram. I've worked recently on making Chimera display multiple copies of identical objects without making copies of the surface in memory -- just reuse the same surface. But it is not in Chimera yet. And your graphics speed will still become unusable if you try to display too many copies with too much detail. So the main need is to show an appropriate low level of detail for all or most of your hundreds of copies. Tom -------- Original Message -------- Subject: Re: [Chimera-users] Using marker files to place oriented density maps inside a tomogram From: Daniel Castano Diez To: Tom Goddard Date: 11/14/12 1:28 PM

Hi Tom,

thanks for the answer. Actually I already wrote some scripts for placing each different copy of the density map as an individual model, but this is not practical for placing hundreds of copies (as it's the case with tomograms). I will try your python script.

I was under the impression that a .cmm markerfile was a better approach, as I though that one could define a marker with more attributes as in the example:

<marker id="1" x="-6.1267" y="17.44" z="-3.1338" radius="0.35217"/>

I mean, something like:

<marker id="1" x="-6.1267" y="17.44" z="-3.1338" map ="my_map.em" matrix = "my_matrix.txt" />

or similar with quaternions or euler angles... but I guess that was wrong? That'll be a pitty, as I am interfacing Chimera with the subtomogram averaging package Dynamo and the most stable way seemes to be having Dynamo converting its "table" files (lists of positions and angles) into .cmm files that could then be directly fed into Chimera.

Thanks!

Daniel

...

Hi Daniel,

Take a look at the placem.py script which can place copies of maps or molecules at specified positions.

http://plato.cgl.ucsf.edu/trac/chimera/wiki/Scripts

It specifies the rotation as a quaternion which is close to a rotation axis and angle description. I could show you how to adapt it to use Euler angles or a 3x3 rotation matrix if you like.

Tom

...

Hi,

I'd like to use a Chimera marker file to place multiple copies of a density map in different spatial positions inside a tomogram. My input is thus a single map file a set of 3d locations, each attached to an euler triplet (or a rotation matrix)

With the documentation I could find

http://www.cgl.ucsf.edu/chimera/1.2065/docs/ContributedSoftware/volumepathtr... it is explained how to place spheres without orientation in a volume, but I was not able to figure out how to place a density map at those locations, and also how to impart a different orientation to the density map located at each position.

My question is: where could I find a description of the marker file syntax that describes this functionality?

thanks, Daniel

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