- Chimera-users - RBVI Mailing Lists

changing the rgb for stereo images
by Bala subramanian 13 Dec '13

13 Dec '13

Friends, I have a glass with a red-cyan color. When i use the Chimera stereo mode (red-cyan) under view controls. I still see some ghost images. I would like to know if there is any possibility to add a features something like a box where i can give the rgb (the light frequencies) values of the images to match my glass. Thank you, Bala -- C. Balasubramanian

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Dynamic scolor custom cmap?
by Hurt, Darrell (NIH/NIAID) [E] 13 Dec '13

13 Dec '13

Hi Chimera friends, I have a volumetric potential file loaded that I want to map onto a molecular surface. For my application, I want the color mapping to use a custom palette of at least three colors that spans the full range of surface values. I know that I can do this by simply specifying the custom colors in the Surface Color panel and then clicking "Set full range of surface values". That works for me. However, I want to do this via command line. The following line works for me (I've omitted "cmapRange full" because that is the default setting): scolor #0 volume #1 offset 1.4 cmap cyanmaroon My problem become if I want to set a custom palette: scolor #0 volume #1 offset 1.4 cmap -10,yellow:0,white:10,green This line also works, but for values lower or higher than –10 or +10, the color ramp "plateaus". And this line only works because the extents of this particular mapping happen to go from –29 to +17. Is it possible to obtain the values for the full range and specify them for a custom palette? Or is it possible to assign a custom palette and call it like the default palettes? I'm happy to clarify if needed. Thanks! Darrell -- Darrell Hurt, Ph.D. Section Head, Computational Biology Bioinformatics and Computational Biosciences Branch (BCBB) OCICB/OSMO/OD/NIAID/NIH 31 Center Drive, Room 3B62B, MSC 2135 Bethesda, MD 20892-2135 Office: 301-402-0095 Mobile: 301-758-3559 Web: BCBB Home Page<http://www.niaid.nih.gov/about/organization/odoffices/omo/ocicb/Pages/bcbb.…> Twitter: @niaidbioit<https://twitter.com/niaidbioit> Disclaimer: The information in this e-mail and any of its attachments is confidential and may contain sensitive information. It should not be used by anyone who is not the original intended recipient. If you have received this e-mail in error please inform the sender and delete it from your mailbox or any other storage devices. National Institute of Allergy and Infectious Diseases shall not accept liability for any statements made that are sender's own and not expressly made on behalf of the NIAID by one of its representatives.

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Modeling with cryo-EM
by Aurore Vaitinadapoule 13 Dec '13

13 Dec '13

Dear all, I'm would like tu use this following script to model with cryo-EM: from modeller import * log.verbose() env = environ() struct='./M60_9.pdb' map='new_map.mrc' resolution=10.2 box_size=48 # how to define the box size ?? apix=1.88 x=90; y=63; z=23 #origin steps=20 # Read in cryo-EM density map den = density(env, file=map, em_density_format='MRC', voxel_size=apix, resolution=resolution, em_map_size=box_size, density_type='GAUSS', px=x,py=y,pz=z) # Fit the PDB file into the map by MC simulated annealing den.grid_search(em_density_format='MRC', num_structures=1, em_pdb_name=struct, chains_num=[1], start_type='CENTER', number_of_steps=steps, angular_step_size=30., temperature=100., best_docked_models=1, translate_type='RANDOM', em_fit_output_file='modem.log') But i got this error message: _modeller.ModellerError: read_mrc_h_E> Density map must be cubic, and of dimension em_map_size (48): actual dimensions (40, 40, 36) What is exactly the box size? And how to define it? Thank's Aurore -- Aurore G. VAÏTINADAPOULÉ aurore <a.vaitinadapoule(a)inserm.fr>.vaitinadapoule(a)inserm.fr<a.vaitinadapoule(a)inserm.fr> a.vaitinadapoule(a)gmail.com PhD Student in Bioinformatics INSERM UMR-S665, DSIMB Team, Dynamique des Structures et des Interactions des Macromolécules Biologiques Mobile phone: +33(0) 778 18 52 07

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chimera slow
by Daniel Murin 12 Dec '13

12 Dec '13

Hi, I have been trying to use the Unit Cell function on Chimera. It works, but the graphic is so large that moving it around is nearly impossible because the program is running so slowly. It is rendered in ribbon. Is there a way to lower the quality in order to manipulate the graphic faster? Thanks! Charles Daniel Murin Ph.D. Candidate - Ward/Ollmann Saphire Labs Integrative Structural and Computational Biology Immunology and Microbial Science Kellogg School of Science and Technology The Scripps Research Institute 10550 North Torrey Pines Road, CimBio 105 La Jolla, CA 92037 Office: 858.784.3326 Lab: 858.784.7170 Fax: 858.784.8218 email: cmurin(a)scripps.edu

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(no subject)
by Danilo Di Maio 12 Dec '13

12 Dec '13

danilo.dimaio(a)gmail.com

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Launch external program from Chimera python script?
by Hurt, Darrell (NIH/NIAID) [E] 11 Dec '13

11 Dec '13

Hi Chimera friends, I am thinking of writing a script for Chimera that allows the user to map lipophilicity to the surface of protein. There are a few algorithms out there, but the easiest that I've found to use is "pyMLP": http://code.google.com/p/pymlp/ I see two ways to do this: (1) Write a wrapper script (shell, Python, etc.) to first run pyMLP to generate a DX file and then launch Chimera with its own script to generate the surface and do the mapping. (2) Write a Chimera Python script to launch pyMLP to get the DX file, generate the surface, and do the mapping. For my purposes, it might be easier in the long run to choose option 2, but that seems a little trickier starting out. Can you advise me on the best way to proceed? Also, I know that you aren't looking to add new functionality to Chimera v1, but the generation of a lipophilicity map might be a nice feature to add to Chimera at some point and pyMLP seems relatively easy to package with Chimera… Thanks, Darrell -- Darrell Hurt, Ph.D. Section Head, Computational Biology Bioinformatics and Computational Biosciences Branch (BCBB) OCICB/OSMO/OD/NIAID/NIH 31 Center Drive, Room 3B62B, MSC 2135 Bethesda, MD 20892-2135 Office: 301-402-0095 Mobile: 301-758-3559 Web: BCBB Home Page<http://www.niaid.nih.gov/about/organization/odoffices/omo/ocicb/Pages/bcbb.…> Twitter: @niaidbioit<https://twitter.com/niaidbioit> Disclaimer: The information in this e-mail and any of its attachments is confidential and may contain sensitive information. It should not be used by anyone who is not the original intended recipient. If you have received this e-mail in error please inform the sender and delete it from your mailbox or any other storage devices. National Institute of Allergy and Infectious Diseases shall not accept liability for any statements made that are sender's own and not expressly made on behalf of the NIAID by one of its representatives.

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Journal of Organic and Biomolecular Simulations: Full page charge waiver
by CompChem News 11 Dec '13

11 Dec '13

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select all side chains
by Zhou, Ming (NIH/NCI) [C] 09 Dec '13

09 Dec '13

Dear Elaine: I have a quick question for you. How should I select all the amino acid side chains in a protein but not the backbone (without CA/C1/N/O). How should I write this command? Thanks Ming Zhou

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Silhouette toggle
by Luca Pellegrini 05 Dec '13

05 Dec '13

Hi, I have set Silhouette ON in the Effects tab of the Viewing panel, and now I would like to toggle it off for one specific object. However, the Attributes window from Model Panel does not show the Silhouette option (it should feature between 'ribbon spline' and 'stick scale'). Can anyone please advice? I am using Chimera 1.9 (build 39137) for Mac . Kind regards, Luca Luca Pellegrini Department of Biochemistry University of Cambridge 80 Tennis Court Road Cambridge CB2 1GA - UK Email: lp212(a)cam.ac.uk Tel: 0044-1223-760469 Fax: 0044-1223-766002 Sanger building, room 3.59

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calculate buried surface area
by Bala subramanian 05 Dec '13

05 Dec '13

Friends, I have a dimer protein (say monomers 1,2). I have calculated the electrostatic potential of monomer 1 using apbs. I used volume viewer to display the electrostatic surface. I see that the elect. surface of one monomer 1, touches the vdw surface of monomer 2 at a contour level of 1. I want to calculate the total surface area of monomer 2 that is exposed/buried within the elec. surface of monomer 1. Is there any simple. If not suggestion how i can do it with a python script perhaps. Thanks, Bala -- C. Balasubramanian

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Problem of Launching Chimera Remotely on a Mac
by Anindito Sen 05 Dec '13

05 Dec '13

Dear All, I am having difficulty to launch Chimera remotely with the following Error message on my Mac. I understand that the current OS X (version 10.8.5) and the latest Xcode has some issues and cannot handle the process ?! Is there a way out of this ? Thanks and Best Wishes Andy [andy@****** ~]$ chimera Xlib: extension "NV-GLX" missing on display "localhost:15.0". Xlib: extension "NV-GLX" missing on display "localhost:15.0". X Error of failed request: GLXBadCurrentWindow Major opcode of failed request: 149 (GLX) Minor opcode of failed request: 5 (X_GLXMakeCurrent) Serial number of failed request: 1354 Current serial number in output stream: 1354 Dr. Anindito Sen (Ph.D) >Department of Cell Biology & Anatomy >Graduate School of Medicine >University of Tokyo >Tel & fax: +81-3-5841-3339

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Electrostatic potential values at each residue
by Tatsuhito Matsuo 04 Dec '13

04 Dec '13

Dear All, I'd like to get the electrostatic potential (ESP) values at each residue in a protein. I implemented the "Coulombic Surface Coloring", then get the distribution of ESP values at each residue by "Render/Select by Attribute" (Attributes of [residues], Select -> Attribute [value_Coulombic_ESP]). However, The surface plot and the ESP values obtained by "Render/Select by Attribute" do not coincide with each other. For example, there are some residues where the surface plot reports positive ESP values, while "Render/Select by Attribute" gives negative ones (e.g. VAL70 CG2 in the Chimera session file attached.). Could you teach me how to solve this discrepancy? Thank you very much in advance, T.M.

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Re: [Chimera-users] Surface area with positive electrostatic potential
by Tom Goddard 04 Dec '13

04 Dec '13

Hi T.M., To find the surface area with positive electrostatic potential would require computing the potential at surface points. Chimera does not compute solvent accessible surface (SAS) points (although it does compute total area). So there is no simple way to get the SAS area for positive potential points. Chimera does compute the solvent excluded surface (SES) using menu Actions / Surface or command "surface". For an SES surface a little Python code can give the fraction of the surface area colored red. I've attached that Python code red_area.py. You color the surface using the normal red-blue electrostatic coloring. The red_area.py code adds a command called "redarea" that computes the area of the surface that is more red than blue. Here's an example from the header of the red_area.py file. # Example use. # # menu File / Open..., red_area.py, Creates the new redarea command. # # open 1a0m # surface # coulombic -10 red 0 white 10 blue #0 # redarea #0 # # menu Favorites / Reply Log # -> "Surface MSMS main surface of 1a0m, red area 1400, total area 1888, ratio 0.7414" This script and other odd Python code for doing computations is on the Chimera developer web site: http://plato.cgl.ucsf.edu/trac/chimera/wiki/Scripts Tom On Dec 3, 2013, at 9:05 PM, Tatsuhito Matsuo wrote: > Dear Tom, > > Thank you very much for the reply and I'm sorry for inadequate information on what I've done (your guess is completely right). What I'd like to know is the ratio of the solvent accessible surface (SAS) with positive (or negative) potential values to the total SAS. The total SAS value is automatically calculated by the surface plot, and I need the value of SAS having positive/negative potential values. > At first, I thought the ESP value of "Attributes of Residues" is relevant to the one at the corresponding protein surface area. I now understand that this was wrong. Could you teach me how to get the SAS having positive/negative potential values? > > Best regards, > > T.M. > > On 2013/12/04, at 12:19, Tom Goddard wrote: > >> Hi T.M., >> >> I think you've left out details about what you have done -- how did you get this value_Coulombic_ESP attribute? Did you use values at atom positions? Did you use the "compute grid" option in the Coulombic Surface Coloring dialog? I guess you did that. And you say you use Attributes of Residues -- is that an average of the atom attribute obtained from the values at atom positions dialog? I can't be sure what you've done, but here's a guess at what your problem is. The Chimera Coulombic Surface Coloring dialog computes the potential at points 1.4 Angstroms out from the solvent excluded molecular surface and colors the surface points using that value. If you instead use a potential value interpolated at the center of an atom, that will give a much different value -- in fact it should tend to give an extremely large value because if the atom is charged the potential at the atom center is infinite using the simple Coulomb calculation. But because you are (I think) using a value interpolated from a grid you don't get an infinite value, just a very large value. So I think your problem is you are not considering that the electrostatic potential varies rapidly in space and you are comparing colors using potential values at different positions in space. >> >> Tom >> >> >> >> On Dec 2, 2013, at 6:31 PM, Tatsuhito Matsuo wrote: >> >>> Dear All, >>> >>> I'd like to get the electrostatic potential (ESP) values at each residue in a protein. I implemented the "Coulombic Surface Coloring", then get the distribution of ESP values at each residue by "Render/Select by Attribute" (Attributes of [residues], Select -> Attribute [value_Coulombic_ESP]). However, The surface plot and the ESP values obtained by "Render/Select by Attribute" do not coincide with each other. For example, there are some residues where the surface plot reports positive ESP values, while "Render/Select by Attribute" gives negative ones (e.g. VAL70 CG2 in the Chimera session file attached.). Could you teach me how to solve this discrepancy? >>> >>> Thank you very much in advance, >>> >>> T.M. >>> >>> <ubiquitin.py><ubiquitin.pyc>_______________________________________________ >>> Chimera-users mailing list >>> Chimera-users(a)cgl.ucsf.edu >>> http://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users >> > >

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request for removal from mailing list
by Aani Homeira 03 Dec '13

03 Dec '13

Thanks . . . . . . . . . . . . . . . . . . . A n i . H o m e i r a . A m i r k h a n i .

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Re: [Chimera-users] reading PDB-format alignment files
by Tom Duncan 03 Dec '13

03 Dec '13

Eric, It's not the structural info I want to extract - just the sequence alignment info. See the remarks in the file header. Thanks, Tom ----------------------------------------------------- Thomas M. Duncan, Ph.D. Associate Professor Dept Biochemistry & Molecular Biology SUNY Upstate Medical University Syracuse, NY On Dec 3, 2013, at 3:00 PM, chimera-users-request(a)cgl.ucsf.edu wrote: > Date: Tue, 3 Dec 2013 11:27:02 -0800 > From: Eric Pettersen <pett(a)cgl.ucsf.edu> > To: Tom Duncan <duncant(a)upstate.edu> > Cc: chimera-users BB <chimera-users(a)cgl.ucsf.edu> > Subject: Re: [Chimera-users] reading PDB-format alignment files > Message-ID: <9EF6E8D1-3C93-4C30-AD51-2B110CF5C813(a)cgl.ucsf.edu> > Content-Type: text/plain; charset="us-ascii" > > On Dec 3, 2013, at 7:47 AM, Tom Duncan <duncant(a)upstate.edu> wrote: > >> Can Chimera read sequence alignments from PDB-format alignment files, such as those generated by the I-Tasser modeling server? Or are there scripts to convert them? I have attached an example file. > > Hi Tom, > Well, this "PDB" file doesn't conform to the PDB standard in a variety of ways, but the one you care about is the extra two columns on the ATOM records. The presence of those columns causes Chimera to skip those records. If you simply edit them out then Chimera displays the structure. I've attached an edited version of your file. I will open an enhancement-request ticket in our bug-tracking database for having Chimera ignore non-standard columns past the coordinate records (there are some standard columns that are supposed to be there!) and put you on the notification list for that ticket. > > --Eric

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reading PDB-format alignment files
by Tom Duncan 03 Dec '13

03 Dec '13

Can Chimera read sequence alignments from PDB-format alignment files, such as those generated by the I-Tasser modeling server? Or are there scripts to convert them? I have attached an example file. Thanks Tom ----------------------------------------------------- Thomas M. Duncan, Ph.D. Associate Professor Dept Biochemistry & Molecular Biology SUNY Upstate Medical University Syracuse, NY

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<< measuring areas >>
by Hatuey Hack 03 Dec '13

03 Dec '13

Hellos ChimeraUsers, It could be possible to measure different parts of a surface according to a given parameter? For example, from the electrostatic potential surface, I would like to know the respective area surface with positive and/or negative values. Best regards, Hatuey

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Information
by Mabel Guzman Rodriguez 02 Dec '13

02 Dec '13

Hello! I few days ago I tried to use your program Chimera, the reason is because I try to make a structure of a multimer protein but I need to know how can I bond the single subunits of the protein to make an hexamer. I hope you can help me. Greetings Mabel G.

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Re: [Chimera-users] Chimera- Imod file size problems
by Elaine Meng 02 Dec '13

02 Dec '13

Hi Ariane, I only know how to do it for "volume data" like MRC files and other density maps, but not for IMOD segmentation mesh (You said "imod mrc" but then it sounded like you meant a segmentation file instead.) <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/filetypes.html#volume> <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/volumeviewer/imod…> If it's a density map, you can adjust voxel size in the Volume Viewer (choose Features… Coordinates to show those settings) <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/volumeviewer/volu…> The same thing can also be done with the volume command, see "dimension and scale options": <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/volume.html> Unless data are private, please send Chimera questions to chimera-users(a)cgl.ucsf.edu instead of only to me. Then If I don't know the answer or am away from work, others can respond. Thanks, Elaine ---------- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco On Dec 2, 2013, at 10:45 AM, Ariane Briegel <ariane.briegel(a)gmail.com> wrote: > Dear Elaine, > I have a question you might have a quick answer to. I am trying to open a model file I generated with the IMOD program. > Generally, when I open Imod mrc files in chimera the pixel size is correct in both programs. With this model the size is way off in chimera (I have never used an imod model in chimera before, just mrc files so far). > See screenshots below- the first one shows that the model has the correct pixel size when opened in IMOD, the second shows the wrong size in chimera (the blue and green layers should have the same height as the crystal structures below), and the last screenshot shows how the data opened in chimera (as a mesh). Is there a way for me to manually adjust the pixel size of a mesh? > If you have any idea how I can fix this issue I would be very grateful! > Thank you! > Ariane > <Screen Shot 2013-12-02 at 10.03.41 AM.png><Screen Shot 2013-12-02 at 10.35.06 AM.png><Screen Shot 2013-12-02 at 10.39.27 AM.png> > –––––––––––––––––––––––––––– > Ariane Briegel, Ph.D. > California Institute of Technology > Broad Center, MC 114-96 > 1200 E. California Blvd. > Pasadena, CA 91125 > > Tel: 626-395-8848 > Fax: 626-395-5730 > –––––––––––––––––––––––––––– > > >

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Query about increasing resolution for vrml export
by Darren Gowers 02 Dec '13

02 Dec '13

Dear Chimera community, Sorry to bother. I'm very interested in trying to increase the vrml export resolution (of any pdb model) so that more polygons are used to describe the curvature of the electron density more smoothly. There is a command in PyMol that does the equivalent (I think it is 'surface_quality'), but I'd rather use Chimera to generate vrml files! Does anyone have any suggestions how to make molecular surfaces much smoother please? Many thanks, Darren -- Dr Darren Gowers<http://www.port.ac.uk/departments/academic/biology/staff/title,30538,en.html> Senior Lecturer in Biochemistry School of Biological Sciences University of Portsmouth PO1 2DY +44(0)2392 842057

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Re: [Chimera-users] solvent-accessible surface area
by Amit Goyal 02 Dec '13

02 Dec '13

Hi Elaine, Today I subscribe to Chimera mailing list, but unable to get the proper way to post a query on it. So I am sending the query this way. I have been reading this post about how to get the areaSAS and areaSES values for any residues. http://www.cgl.ucsf.edu/pipermail/chimera-users/2008-May/002617.html Still, I think, is there any specific values/range for the areas AS to decide whether a particular amino acid residues is buried or exposed to the solvent. Hoping for Thanks for your help. Sincerely, AMIT -- AMIT GOYAL, Pusan National University, Korea south. amitgsir(a)pusan.ac.kr

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translation matrix
by Antón Vila Sanjurjo 02 Dec '13

02 Dec '13

Hi, I'm trying to get a translation matrix for two different crystal structures of ribisomal subunits. I've been trying to use the "measure rotation" command but I can only get it to display the following message "rotation angle is near zero (0 degrees)". I was wondering whether the command might be failing due to the fact that the ribosome contains numerous chains, or perhaps because the command does not deal with RNA. At any rate, how would one go about obtaining a translation matrix that can be applied to any model? best, Antón -- Antón Vila-Sanjurjo, PhD Marie Curie fellow Grupo QOSBIOS, Dept. Química Fundamental Facultade de Ciencias Universidade de A Coruña (UDC) Campus Zapateira, s/n 15.071 - A Coruña - España (Spain). tlf: (34) 981-167000 ext:2659 e-mail: antonvila.s(a)gmail.com

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colouring according to hydrophobicity
by Dieter Blaas 29 Nov '13

29 Nov '13

Hi, I am wondering whether there is any (easy) way of colouring a volume (e.g. an MRC file made from a pdb file and filtered to say, 10 A with e.g. xmipp) according to hydrophobicity (using the values derived from the amino acid residues in the pdb file)? I am aware of the way to colour the van der Waals surface but the resolution is somewhat too high not allowing to get a more general view, for example whether the molecule is more hydrophobic on one side than on another side. The same question applies to the charge distribution.... Thanks, Dieter -- ------------------------------------------------------------------------ Dieter Blaas, Max F. Perutz Laboratories Medical University of Vienna, Inst. Med. Biochem., Vienna Biocenter (VBC), Dr. Bohr Gasse 9/3, A-1030 Vienna, Austria, Tel: 0043 1 4277 61630, Fax: 0043 1 4277 9616, e-mail: dieter.blaas(a)meduniwien.ac.at ------------------------------------------------------------------------

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Overlay binding sites
by Markus Heller 28 Nov '13

28 Nov '13

Hello all, I'm pretty sure this has been done before, so before re-inventing the wheel or failing miserably and doing everything by hand, I thought I'd ask here first :) I have a protein that has been crystallized with about a dozen ligands of different sizes. I'd like to overlap the protein residues forming the binding site. My plan was to pick the 2 largest ligands, select all protein residues within say 7 A, and consider these to be the residues forming the binding site. Then, I'd like to match this set of residues for all proteins to the same reference. I suppose I could do this all manually, but I'm hoping that there is a quicker, more efficient way! Any tips are appreciated! Thanks and Cheers Markus -- Markus Heller, Ph.D. NMR Scientist CDRD - The Centre for Drug Research and Development 2405 Wesbrook Mall, Fourth Floor | Vancouver, BC V6T 1Z3 | Main: (604) 827-1147 Direct: (604) 827-1122 | F: (604) 827-1299 | E: mheller(a)cdrd.ca<mailto:mheller@cdrd.ca> | www.cdrd.ca [cid:image007.png@01CEEC32.879D5C80] Follow us: [Description: cid:image003.jpg@01CD86A6.39B41A10] <https://twitter.com/C_D_R_D> [Description: cid:image005.jpg@01CD86AE.B197F5D0] <http://www.linkedin.com/groups/CDRD-3186016/about?report%2Esuccess=3NcE4iZo…> [Description: cid:image009.png@01CD86AE.B197F5D0] <https://www.facebook.com/pages/The-Centre-for-Drug-Research-and-Development…> [Description: cid:image010.png@01CD86AE.B197F5D0] <http://www.youtube.com/user/CDRDCVI?view_as=public> This email and any files transmitted with it are confidential and intended solely for the addressee. If you are not the named addressee you should not disseminate, distribute, copy, or alter this email.

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features/question: stereo3d and volume rendering
by Dougherty, Matthew T 28 Nov '13

28 Nov '13

1) I have been doing S3D animations. One of things I am realizing is that I need to frequently adjust the interaxial and screen distances. Sometimes my IA might be 1mm or it might be 23 inches depending on the shot. Currently chimera does not maintain this camera metadata, so every session I need to reset the values which makes my animations slightly different. Since rendering can take several hours, one typo can trash the effort. Any suggestions on a workaround? There is also a linkage between IA, horizontal field of view, and screen distance, sometimes I think I get caught in a hysteresis loop trying to converge to the desired shot. As a note, I pretty much stopped using the zoom and have gone to dolly, keeping the scale to one. 2) when doing volume rendering of electron tomograms I am finding it useful to load the same mrc map file in multiple times, such that each model has a different transfer function relating to different densities or structures. I can currently load seven, but four must be changed from floating point to byte in order to prevent memory lockout thrashing, error messages, etc. Is there a way to load a single map file in and have multiple models and transfer functions for the solid viewing? Matthew Dougherty National Center for Macromolecular Imaging Baylor College of Medicine

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