Hi Stephen, This is not an artificial Open Source PyMOL limitation.
PyMOL's ray tracing code was written at a time when probably nobody had a computer with 64GB of RAM, or at least didn't attempt to ray trace images that size. The code is pretty hard to read and understand, and currently there is nobody who's familiar with it and could easily fix such a limitation. I assume the code makes an assumption which is only true up to a certain memory address range. Cheers, Thomas On 12 May 2016, at 10:20, Stephen Kerry <stephen.kerr...@outlook.com> wrote: > So the images are back from the printers and I can easily tell the difference > between 180 and 300 dpi. You have to look closely to tell the difference > between 300 and 600 dpi. I am unable to distinguish between 600 and 1200 dpi. > > My image size is still limited to 7500 x 6000, which at 600 dpi gives a 12.5 > x 10 inch image. Is this an artificial Open Source PyMOL software limitation > or a genuine bug/memory leak? The segmentation faults also seems to happen > even with 128 GB and 256 GB of RAM! > > On my system with 32 GB of RAM, I see PyMOL reserves more virtual RAM than > the amount of physical RAM, which might be why it crashes when trying to > write the PNG at the end of ray tracing? It does not appear to use this > virtual RAM or even compress any RAM, according to activity monitor on OSX > 10.10. Disabling memory compression and/or swap makes no difference. > > Is there anything else I can try to successfully output such a large image? > > ________________________________________ > From: Thomas Holder <thomas.hol...@schrodinger.com> > Sent: 10 May 2016 20:34:44 > To: harold steinberg > Cc: Stephen Kerry; pymol-users@lists.sourceforge.net > Subject: Re: [PyMOL] High Resolution Ray Tracing > > Hi Adam et al., > > This is a super interesting and helpful discussion! > > Just wanted to throw in the following shortcut for creating the 6" test > images: > > png image1.png, 6in, ray=1, dpi=180 > png image2.png, 6in, ray=1, dpi=300 > png image3.png, 6in, ray=1, dpi=600 > png image4.png, 6in, ray=1, dpi=1200 > > Cheers, > Thomas > > On 10 May 2016, at 14:27, harold steinberg <h.adam.steinb...@gmail.com> wrote: > >> The 9600 x 4800 is a very common poster printer spec. Most print shops use >> 180 dpi images on their poster printers (for best print speed) and customers >> cannot tell the difference between that and a higher resolution. >> >> As a test, render a small image (say 6” x 6”) in PyMOL at four different >> dpi, 180 dpi (ray 1080), 300 dpi (ray 1800), 600 dpi (ray 3600) and 1200 dpi >> (ray 7200). Then use Photoshop or GIMP to make them all 6” x 6”. >> >> Put them together side-by-side in a layout program and print them on one >> sheet to compare. I bet you will have an extremely difficult time telling >> them apart. >> >>> On May 10, 2016, at 12:40 PM, Stephen Kerry <stephen.kerr...@outlook.com> >>> wrote: >>> >>> Harold, I agree 2400 dpi might be wasted, but the professional printer >>> supports up to 9600 horizontal dpi x 4800 vertical dpi, so a source image >>> with 1200 dpi would be a nice step up from 600 dpi. The lpi is 1200 as the >>> four passes from each CMYK component apparently increases the vertical dpi >>> by four. >> >> H. Adam Steinberg >> 7904 Bowman Rd >> Lodi, WI 53555 >> 608/592-2366 -- Thomas Holder PyMOL Principal Developer Schrödinger, Inc. ------------------------------------------------------------------------------ Mobile security can be enabling, not merely restricting. Employees who bring their own devices (BYOD) to work are irked by the imposition of MDM restrictions. Mobile Device Manager Plus allows you to control only the apps on BYO-devices by containerizing them, leaving personal data untouched! https://ad.doubleclick.net/ddm/clk/304595813;131938128;j _______________________________________________ PyMOL-users mailing list (PyMOL-users@lists.sourceforge.net) Info Page: https://lists.sourceforge.net/lists/listinfo/pymol-users Archives: http://www.mail-archive.com/pymol-users@lists.sourceforge.net
