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    Hi Edu,<br>
    <br>
      Chimera uses MSMS to calculate solvent excluded surfaces (SES) and
    per-atom values of solvent excluded surface area (SESA) and solvent
    accessible surface area (SASA).  Chimera does not currently display
    solvent accessible surfaces, only solvent excluded surfaces.<br>
    <br>
      To do these calculations Chimera calls a standalone program that I
    wrote called mscalc which uses the MSMS library.  The mscalc program
    takes two command-line arguments: probe radius and vertex density. 
    Then it reads from standard input an integer N saying how many atoms
    there are followed by an N by 4 array of (x,y,z,radius) float values
    describing the centers and radii of each atom.  It writes the
    results to standard output including triangles composing the surface
    and areas per-atom.  Both the input xyzr array and the output are in
    binary (not text) format.  Calling the standalone program is done by
    Python code in your Chimera distribution<br>
    <br>
        chimera/share/MoleculeSurface/calcsurf.py<br>
    <br>
    This is also in the Chimera source code online<br>
    <br>
       
<a class="moz-txt-link-freetext" href="http://plato.cgl.ucsf.edu/trac/chimera/browser/trunk/libs/MoleculeSurface/calcsurf.py">http://plato.cgl.ucsf.edu/trac/chimera/browser/trunk/libs/MoleculeSurface/calcsurf.py</a><br>
    <br>
    Take a look at the run_mscalc and parse_mscalc_output functions to
    see exactly how the output of the mscalc program is formatted.  The
    mscalc C program is attached to this email.  (It is not online
    because we keep it with the MSMS source code which we are not
    allowed to release because of licensing issues.)<br>
    <br>
      You should be able to simply replace the Chimera mscalc program in
    your copy of Chimera with your own program that takes equivalent
    input and produces equivalent output.<br>
    <br>
        chimera/bin/mscalc<br>
    <br>
    We'll be very interested to see your results and consider including
    them in Chimera.  Let us know if you run into problems.<br>
    <br>
        Tom<br>
    <br>
    <br>
    <br>
    -------- Original Message --------<br>
    Subject: [chimera-dev] Fwd: SASA calculation in Chimera<br>
    From: Elaine Meng <br>
    Date: 11/15/11 9:06 AM<br>
    <blockquote
      cite="mid:0D8E370D-DD05-45A8-84F9-866086836CFA@cgl.ucsf.edu"
      type="cite">Hi Edu,
      <div>I don't do any of the Chimera programming (I do testing,
        documentation, web content), so I can only forward your question
        to the developers/programmers.</div>
      <div><br>
      </div>
      <div>It may be possible to have your surface calculation as a
        separate extension instead of integrated into the Chimera core,
        but I'm guessing integration has some advantages... perhaps
        computational efficiency?</div>
      <div><br>
      </div>
      <div>Programmers who have worked on surface calculations in
        Chimera should have better or more complete answers for you.
         However, please bear with us, as this week is especially busy
        for our group.</div>
      <div>Best,</div>
      <div>Elaien</div>
      <div>
        <div>
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            <div>-----</div>
            <div>Elaine C. Meng, Ph.D.                       </div>
            <div>UCSF Computer Graphics Lab (Chimera team) and Babbitt
              Lab</div>
            <div>Department of Pharmaceutical Chemistry</div>
            <div>University of California, San Francisco</div>
            <div><br>
            </div>
          </span></div>
        <div>
          <div>Begin forwarded message:</div>
          <br class="Apple-interchange-newline">
          <blockquote type="cite">
            <div style="margin-top: 0px; margin-right: 0px;
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                style="font-family:'Helvetica'; font-size:medium;
                color:rgba(0, 0, 0, 1);"><b>From: </b></span><span
                style="font-family:'Helvetica'; font-size:medium;">Eduardo
                José Cepas Quiñonero<br>
              </span></div>
            <div style="margin-top: 0px; margin-right: 0px;
              margin-bottom: 0px; margin-left: 0px;"><span
                style="font-family:'Helvetica'; font-size:medium;
                color:rgba(0, 0, 0, 1);"><b>Date: </b></span><span
                style="font-family:'Helvetica'; font-size:medium;">November
                15, 2011 3:19:17 AM PST<br>
              </span></div>
            <div style="margin-top: 0px; margin-right: 0px;
              margin-bottom: 0px; margin-left: 0px;"><span
                style="font-family:'Helvetica'; font-size:medium;
                color:rgba(0, 0, 0, 1);"><b>To: </b></span><span
                style="font-family:'Helvetica'; font-size:medium;">Elaine
                Meng<br>
              </span></div>
            <div style="margin-top: 0px; margin-right: 0px;
              margin-bottom: 0px; margin-left: 0px;"><span
                style="font-family:'Helvetica'; font-size:medium;
                color:rgba(0, 0, 0, 1);"><b>Subject: </b></span><span
                style="font-family:'Helvetica'; font-size:medium;"><b>Re:
                  SASA calculation in Chimera</b><br>
              </span></div>
            <br>
            Hi Elaine,
            <div><br>
            </div>
            <div>I'm Edu, colleague of Horacio. I would like to ask you
              several things related to the previous question he asked.</div>
            <div><br>
            </div>
            <div>As Horacio said before, we have developed a new SASA
              calculation method. Our intention is to integrate it into
              Chimera, as another way to calculate the data Chimera
              needs to show molecular solid surfaces (instead of using
              msms).</div>
            <div><br>
            </div>
            <div>Since Chimera doesn't call msms executable, but it has
              msms integrated into it, we assume that whe have to adapt
              our method to Chimera, and compile both together, right?¿
              If not,  Is there another simple way to change the method
              Chimera uses to calculate molecular surfaces?¿</div>
            <div><br>
            </div>
            <div>Then, after reading the link</div>
            <div><br>
            </div>
            <div><a moz-do-not-send="true"
                href="http://www.cgl.ucsf.edu/chimera/sourcecode.html">http://www.cgl.ucsf.edu/chimera/sourcecode.html</a></div>
            <div><br>
            </div>
            <div>we realize that this can be a really complex
              purpose...:</div>
            <div><br>
            </div>
            <div>"<span class="Apple-style-span" style="font-family:
                'Times New Roman'; background-color: rgb(255, 255, 255);
                font-size: medium; ">Compiling Chimera requires building
                over 40 third-party packages and is not recommended</span>"</div>
            <div><br>
            </div>
            <div>"<span class="Apple-style-span" style="font-family:
                'Times New Roman'; background-color: rgb(255, 255, 255);
                font-size: medium; "> </span><span
                class="Apple-style-span" style="font-family: 'Times New
                Roman'; background-color: rgb(255, 255, 255); font-size:
                medium; ">creating a full build-from-source copy of
                Chimera is a lot of work and depends on getting a bunch
                of things in the build environment set up just right for
                your particular platform. Currently we do not have any
                documentation describing the build environment or
                procedure.</span>"</div>
            <div><br>
            </div>
            <div><br>
            </div>
            <div>Could we have some help on this¿? Could you advice us?</div>
            <div><br>
            </div>
            <div>Thanks in advance,</div>
            <div>Edu.</div>
            <div><br>
              <br>
              <div class="gmail_quote">
                <blockquote class="gmail_quote" style="margin:0 0 0
                  .8ex;border-left:1px #ccc solid;padding-left:1ex;">
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                      <div><br>
                        <blockquote type="cite">
                          <div
style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px"><span
style="font-family:'Helvetica';font-size:medium"><b>From: </b></span><span
style="font-family:'Helvetica';font-size:medium">Elaine Meng<br>
                            </span></div>
                          <div
style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px"><span
style="font-family:'Helvetica';font-size:medium"><b>Subject: </b></span><span
style="font-family:'Helvetica';font-size:medium"><b>Re: SASA calculation
                                in Chimera</b><br>
                            </span></div>
                          <div
style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px"><span
style="font-family:'Helvetica';font-size:medium"><b>Date: </b></span><span
style="font-family:'Helvetica';font-size:medium">21 September , 2011
                              7:13:29 PM GMT+02:00<br>
                            </span></div>
                          <div
style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px"><span
style="font-family:'Helvetica';font-size:medium"><b>To: </b></span><span
style="font-family:'Helvetica';font-size:medium">Horacio Pérez-Sánchez<br>
                            </span></div>
                          <div
style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px"><span
style="font-family:'Helvetica';font-size:medium"><b>Cc: </b></span><span
style="font-family:'Helvetica';font-size:medium"><a
                                moz-do-not-send="true"
                                href="mailto:chimera-users@cgl.ucsf.edu"
                                target="_blank">chimera-users@cgl.ucsf.edu</a><br>
                            </span></div>
                          <div
style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px"><span
style="font-family:'Helvetica';font-size:medium"><b>Reply-To: </b></span><span
style="font-family:'Helvetica';font-size:medium">"<a
                                moz-do-not-send="true"
                                href="mailto:chimera-users@cgl.ucsf.edu"
                                target="_blank">chimera-users@cgl.ucsf.edu</a>
                              List" <<a moz-do-not-send="true"
                                href="mailto:chimera-users@cgl.ucsf.edu"
                                target="_blank">chimera-users@cgl.ucsf.edu</a>><br>
                            </span></div>
                          <br>
                          <div>Hi Horacio,<br>
                            Chimera is using MSMS to generate the
                            surface and give surface area values per
                            atom.  There is more information and an MSMS
                            reference here:<br>
                            <br>
                            <<a moz-do-not-send="true"
href="http://plato.cgl.ucsf.edu/chimera/docs/UsersGuide/representation.html#surfaces"
                              target="_blank">http://plato.cgl.ucsf.edu/chimera/docs/UsersGuide/representation.html#surfaces</a>><br>
                            <br>
                            I hope this helps,<br>
                            Elaine<br>
                            -----<br>
                            Elaine C. Meng, Ph.D.                       <br>
                            UCSF Computer Graphics Lab (Chimera team)
                            and Babbitt Lab<br>
                            Department of Pharmaceutical Chemistry<br>
                            University of California, San Francisco<br>
                            <br>
                            On Sep 21, 2011, at 9:01 AM, Horacio
                            Pérez-Sánchez wrote:<br>
                            <br>
                            <blockquote type="cite">We have developed a
                              fast and accurate new GPU based SASA
                              calculation method. It can bring
                              information about SASA per atom and also
                              grid per atom necessary to graphically
                              render the molecular surface. We are new
                              to Chimera but we would like to know:<br>
                            </blockquote>
                            <blockquote type="cite"><br>
                            </blockquote>
                            <blockquote type="cite">a) where could we
                              find information about the SASA method
                              Chimera uses so we can test with our own
                              method<br>
                            </blockquote>
                            <blockquote type="cite">
                              b) same question for the method Chimera
                              uses to graphically render the molecular
                              surface<br>
                            </blockquote>
                            <blockquote type="cite"><br>
                            </blockquote>
                            <blockquote type="cite">Thanks in advance,<br>
                            </blockquote>
                            <blockquote type="cite">
                              Horacio<br>
                            </blockquote>
                            <blockquote type="cite"><br>
                            </blockquote>
                            <blockquote type="cite"><br>
                            </blockquote>
                            <br>
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===============================================================================================<br>
                              Horacio Pérez-Sánchez, PhD<br>
                              Grupo de Arquitectura y Computación
                              Paralela<span> </span><span
                                style="white-space:pre-wrap"> </span>  
                                           | Parallel Computer
                              Architecture Group<br>
                              Departamento de Ingeniería y Tecnología de
                              Computadores        | Computer Engineering
                              and Technology Department<br>
                              Facultad de Informática<span> </span><span
                                style="white-space:pre-wrap"> </span>| School
                              of Computer Science<br>
                              Universidad de Murcia<span
                                style="white-space:pre-wrap"> </span>|
                              University of Murcia<br>
                              Campus de Espinardo - 30080 Murcia (Spain)<br>
===============================================================================================<br>
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