Area light creates whiteness only through glass So I have an animated scene where the camera goes through a window into a house. The only issue is that the ceiling of the house is white (EDIT: it's actually not the ceiling, but the area lamp that's inside — see edit log at the bottom) while the camera looks into it from outside and I have no idea why. On top of that, a character's head is partially cut off, too - only when rendered through the glass.  PROBLEM:    [Rendered looking THROUGH the window]      [Rendered from INSIDE]    SCENE:    [This is what the scene looks like with the window plane hidden via "H"]      [These are the material properties of the glass. It's also been extruded.]      [And these are the materials of the house. Regular image textures UV unwrapped and assigned to the necessary faces.]    RENDER SETTINGS:  GPU rendering Cycles 1080*1920/25 Clamp direct: 1.11 Clamp indirect: 1.17 100 samples Bounces: between 5 and 0; Diffuse: 2; Glossy: 2; Transmission: 12 1/50 motion blur 256*256 spiral  The rest is set to default.    If you have any idea on how to solve this, please share it with me.  EDIT: So I just realised that the whiteness might not be the house itself, but the AREA LAMP that's inside!! And the guy's head is cut off, since that part is in the physical area of the lamp object! Now the only thing I don't know is what to change. If I simply rised the lamp, it would cure the problem with the guy's head, but the whiteness would still be there.  The lamp is - as I already said - an aerial light, its size is 3.433 , max bounces: 1024 , streght: 30
Prevent area light from being reflected on glass? I did setup an easy scene with an area light behind a window. In the glass (simple plane) which is in front the area light is visible - how can I turn this off so that the background is shining throgh?
How to change the language for the front-end only? How to install gnome shell extensions offline? I know how to go to the  website and download gnome-shell extensions, but now I need to install some extensions available there on a computer without any internet access at all. It is in a internal corporate network and there's no way I can get outside internet access on it, so I must find another way. I can copy files in a usb disk.   At my home computer, I have found my extensions at ~/.local/share/gnome-shell/extensions/ but just copying this folder to the target corporate computer didn't do the trick.   Running gnome-tweak-tool gives me a "Install Shell Extension" button but I don't know how to download an extension in a format acceptable to install using this button. I have tried to point to the folder above but it didn't work either.  What do I need to do? Roots of unity filter, identity involving $\sum_{k \ge 0} \binom{n}{3k}$ How do I see that$$\sum_{k \ge 0} \binom{n}{3k} = (1 + 1)^n + (\omega + 1)^n + (\omega^2 + 1)^n,$$where $\omega = \text{exp}\left({2\over3}\pi i\right)$? What is the underlying intuition behind this equality? Bias and variance in leave-one-out vs K-fold cross validation How do  methods compare in terms of model variance and bias?   My question is partly motivated by this thread: . The answer there suggests that models learned with leave-one-out cross-validation have higher variance than those learned with regular $K$-fold cross-validation, making leave-one-out CV a worse choice.  However, my intuition tells me that in leave-one-out CV one should see relatively lower variance between models than in the $K$-fold CV, since we are only shifting one data point across folds and therefore the training sets between folds overlap substantially.  Or going in the other direction, if $K$ is low in the $K$-fold CV, the training sets would be quite different across folds, and the resulting models are more likely to be different (hence higher variance).  If the above argument is right, why would models learned with leave-one-out CV have higher variance? Overlapping matches in Regex Let $G$ be a connected planar graph with a planar embedding where every face boundary is a cycle of even length. Prove that $G$ is bipartite.  Any hints/tips will be greatly appreciated. This looks a little bit like a variation on  but specific to the tags view.  Reproduction (app version 1.0.71):   Select any site (say Meta) from the sidebar Switch to the tags view using the top bar Choose a tag, any tag ( is nice)   optionaly refine your search with more terms  Go to any question found, go back   you end on the unfiltered tags view  Go back again   lucky you, your search is here What does a resistor do? OK, very basic question here.  I read lots of books, searched quite a bit, and every description I read seemed to talk about the flow of electrons and right away go too deep in theory for me to grasp the basic principle of their use.  I understand a resistor limits the "flow", so that an LED doesn't blow up for example. But I fail to understand exactly what a resistor does to current and voltage...  Do resistors affect both current and voltage? In what manner? PHP: running scheduled jobs (cron jobs) I have a site on my webhotel I would like to run some scheduled tasks on. What methods of achieving this would you recommend?  What I’ve thought out so far is having a script included in the top of every page and then let this script check whether it’s time to run this job or not.  This is just a quick example of what I was thinking about:  if ($alreadyDone == 0 &amp;&amp; time() &gt; $timeToRunMaintainance) {    runTask();    $timeToRunMaintainance = time() + $interval; }    Anything else I should take into consideration or is there a better method than this? Hide textfield blinking cursor MacTEX-2014, TeXShop 3.36.1 on Mac OS 10.9.5 -- when using hyperref I do not see the colored border that should appear around the hyperlinks in the pdf.  for example, when compiled with pdflatex, the code below should produce a pdf with a green border around the link on the right of "abc", but it does not. Any idea how to check where the problem is?  \documentclass{article} \usepackage{hyperref} \hypersetup{colorlinks=false,pdfborder=0 0 1,citebordercolor={0 1 0}} \begin{document}  abc \cite{123}  \begin{thebibliography}{99} \bibitem{123} efg \end{thebibliography} \end{document}    this is the list of files from the generated .log     File List   article.cls    2007/10/19 v1.4h Standard LaTeX document class   size10.clo    2007/10/19 v1.4h Standard LaTeX file (size option)   hyperref.sty    2012/11/06 v6.83m Hypertext links for LaTeX   hobsub-hyperref.sty    2012/05/28 v1.13 Bundle oberdiek, subset hyperref (HO)   hobsub-generic.sty    2012/05/28 v1.13 Bundle oberdiek, subset generic (HO)     hobsub.sty    2012/05/28 v1.13 Construct package bundles (HO)   infwarerr.sty    2010/04/08 v1.3 Providing info/warning/error messages (HO)    ltxcmds.sty    2011/11/09 v1.22 LaTeX kernel commands for general use (HO)   ifluatex.sty    2010/03/01 v1.3 Provides the ifluatex switch (HO)     ifvtex.sty    2010/03/01 v1.5 Detect VTeX and its facilities (HO)    intcalc.sty    2007/09/27 v1.1 Expandable calculations with integers (HO)      ifpdf.sty    2011/01/30 v2.3 Provides the ifpdf switch (HO)   etexcmds.sty    2011/02/16 v1.5 Avoid name clashes with e-TeX commands (HO)   kvsetkeys.sty    2012/04/25 v1.16 Key value parser (HO)   kvdefinekeys.sty    2011/04/07 v1.3 Define keys (HO)   pdftexcmds.sty    2011/11/29 v0.20 Utility functions of pdfTeX for LuaTeX (HO)   pdfescape.sty    2011/11/25 v1.13 Implements pdfTeX's escape features (HO)   bigintcalc.sty    2012/04/08 v1.3 Expandable calculations on big integers (HO)     bitset.sty    2011/01/30 v1.1 Handle bit-vector datatype (HO)   uniquecounter.sty    2011/01/30 v1.2 Provide unlimited unique counter (HO)   letltxmacro.sty    2010/09/02 v1.4 Let assignment for LaTeX macros (HO)    hopatch.sty    2012/05/28 v1.2 Wrapper for package hooks (HO)   xcolor-patch.sty    2011/01/30 xcolor patch   atveryend.sty    2011/06/30 v1.8 Hooks at the very end of document (HO)   atbegshi.sty    2011/10/05 v1.16 At begin shipout hook (HO)   refcount.sty    2011/10/16 v3.4 Data extraction from label references (HO)    hycolor.sty    2011/01/30 v1.7 Color options for hyperref/bookmark (HO)     keyval.sty    2014/05/08 v1.15 key=value parser (DPC)    ifxetex.sty    2010/09/12 v0.6 Provides ifxetex conditional    auxhook.sty    2011/03/04 v1.3 Hooks for auxiliary files (HO)   kvoptions.sty    2011/06/30 v3.11 Key value format for package options (HO)     pd1enc.def    2012/11/06 v6.83m Hyperref: PDFDocEncoding definition (HO)   hyperref.cfg    2002/06/06 v1.2 hyperref configuration of TeXLive        url.sty    2013/09/16  ver 3.4  Verb mode for urls, etc.    hpdftex.def    2012/11/06 v6.83m Hyperref driver for pdfTeX   rerunfilecheck.sty    2011/04/15 v1.7 Rerun checks for auxiliary files (HO)    nameref.sty    2012/10/27 v2.43 Cross-referencing by name of section   gettitlestring.sty    2010/12/03 v1.4 Cleanup title references (HO) I accidentally removed some files on a NTFS partition  How can I recover them staying inside Linux without rebooting ? Does the sign of scores or of loadings in PCA or FA have a meaning? May I reverse the sign? Java ReentrantReadWriteLocks - how to safely acquire write lock? I am using in my code at the moment a  to synchronize access over a tree-like structure.  This structure is large, and read by many threads at once with occasional modifications to small parts of it - so it seems to fit the read-write idiom well.  I understand that with this particular class, one cannot elevate a read lock to a write lock, so as per the Javadocs one must release the read lock before obtaining the write lock.  I've used this pattern successfully in non-reentrant contexts before.  What I'm finding however is that I cannot reliably acquire the write lock without blocking forever.  Since the read lock is reentrant and I am actually using it as such, the simple code  lock.getReadLock().unlock(); lock.getWriteLock().lock()  can block if I have acquired the readlock reentrantly.  Each call to unlock just reduces the hold count, and the lock is only actually released when the hold count hits zero.    EDIT to clarify this, as I don't think I explained it too well initially - I am aware that there is no built-in lock escalation in this class, and that I have to simply release the read lock and obtain the write lock.  My problem is/was that regardless of what other threads are doing, calling getReadLock().unlock() may not actually release this thread's hold on the lock if it acquired it reentrantly, in which case the call to getWriteLock().lock() will block forever as this thread still has a hold on the read lock and thus blocks itself.  For example, this code snippet will never reach the println statement, even when run singlethreaded with no other threads accessing the lock:  final ReadWriteLock lock = new ReentrantReadWriteLock(); lock.getReadLock().lock();  // In real code we would go call other methods that end up calling back and // thus locking again lock.getReadLock().lock();  // Now we do some stuff and realise we need to write so try to escalate the // lock as per the Javadocs and the above description lock.getReadLock().unlock(); // Does not actually release the lock lock.getWriteLock().lock();  // Blocks as some thread (this one!) holds read lock  System.out.println("Will never get here");   So I ask, is there a nice idiom to handle this situation?  Specifically, when a thread that holds a read lock (possibly reentrantly) discovers that it needs to do some writing, and thus wants to "suspend" its own read lock in order to pick up the write lock (blocking as required on other threads to release their holds on the read lock), and then "pick up" its hold on the read lock in the same state afterwards?  Since this ReadWriteLock implementation was specifically designed to be reentrant, surely there is some sensible way to elevate a read lock to a write lock when the locks may be acquired reentrantly?  This is the critical part that means the naive approach does not work. In Salesforce Marketing Cloud (SFMC), I want to unsubscribe a contact from a single publication list by using a form on a landing page.  I also want to create an Unsub event in SFMC when they submit the form.  There is some sample code from SFMC Help documents  that seems to do that for external sites. Will it work in a SFMC hosted landing page? Do I need to edit the code much? This is a canonical question that will hopefully encompass all of the questions we get asking us to determine what year a bicycle was manufactured (how old is my bike, how old is my frame, etc.). Each "answer" should address a different way to determine the manufacturing year of a bicycle. To some extent, these will also help you narrow down the model as well as it will tell you what distinguishing features to look at.  The span of answers would include things such as:      Skiptooth cranks Cartridge bottom brackets (BB30/90 etc) Elliptical chainring Quick releases versus contemporary through-axles How the steerer attaches to the fork (quill vs. threadless)  Braking system (especially with mountain bikes: v-brake, direct pull, etc.)   Shifting ramps and pins on cassettes/sprockets and chainrings (versus flat sprockets) Frame material (e.g., shift from tubular steel to use of CF and hydroformed aluminium)  Frame tubing type (e.g. Reynolds 531 tubing introduced around 1934, still used today; Reynolds 501 tubing introduced around 1983). So a frame with an original 501 decal can't be from the 70', 531 decal doesn't help as much because of the range of years produced. Also, see Decals.   *Decals: style/design, amount, placement, color, etc. can help not only determine models, but also year of manufacture. Many changed decal design for the same model bike often yearly, with special/limited editions even more specific. This applies only if decals are original or have been replaced with the identical design. Tubing decals (Reynolds, Columbus, etc.) also changed designs for same tubing made in different years, although the changes aren't made as often, and manufacturers didn't always put tubing Brand decals on every model. Earlier bikes tended to have less fancy, less colorful, less quantity of decals.   Headbadges: most early bikes had actual "badges", often quite detailed and fancy, made of metal, then plastic, and finally just using decals on the headtube. Most bikes lost their metal badges in the 60's and early 70's, although some brands still have actual badges to this day, but in general a real badge indicates an earlier model bike. Dropout style (including the later inclusion of lawyers lips) Presence or absence of CPSC reflectors (USA only) Manufacturing method (shift from lugs to TIG welding, for example)  Number of gears (shift from 2x5 ten-speed to 3x8, 2x9, 1x11, etc.)  Inspection of lug design: pantographs, cut-out, stampings, custom brazing/filing, chrome, fork crow n sweep, etc. Frame/Fork Braze-ons. Race bikes tended have less braze-ons the earlier the year of manufacture. Most 60's racers and earlier had few or none with cable guides/stops, shifters, bidons, etc. being clamp-on. By the 80's if it was clamp-on, it was a sign of very cheap models and most frames had braze-ons for all cables, with multiple bottle and accessory bosses depending on style and use.   and so forth. Please edit this question if you have an answer that isn't in the index above.   A couple of caveats:   A previous owner could have replaced or upgraded components on a bicycle, so this guide only applies to original equipment There is a delay between the introduction of a technology (such as indexed shifting) and when manufacturers start selling products that use it. Low-end manufacturers may continue using technology that is severely outdated (such as one-piece cranks, freewheels, or quill stems) because it is cheaper to do so. A number of bikes are built in a Retro style, but with modern components.  Dutch bikes, trendy coffee cruisers, and beach cruisers may be modern but appear to be 1950s styling.  These tend to have modern rims and brakes as a giveaway.     Note that bicycles.stackexchange does not do valuations of bicycles. How much your bicycle is worth depends on the location of the buyer and seller, how much the buyer wants the bike, etc. etc. etc. Newman's "Natural proof"(Analytic) of Prime Number Theorem (1980) I am trying to understand this short proof by newmann. I faced some problems while grasping this very proof. Please help me out.  1 . I am not clear, why in step (1)'s proof he says that from unique factorization and the absolute convergence of zeta we have... [here factorization makes sense but where did he use absolute convergence to prove (1).]  2 . Step 2 is clear but where will he use it (may be I will out later as i am still working on next steps.  3 . My major problem is to understand step 3rd's last part that i put it in the red box. please elaborate it. I didn't understand anything in this box.  I am still working on the next steps of the proofs. If i get any problem in them i will ask you.  Thank you so much in advance. This is fairly easy.  If I go to https://webserver.com/someurl?a=b, will the someurl?a=b part be protected, or just the contents of the site? Can I leave South Africa before my 90 days expire, and return after a few days to stay for another 90 days? How many times can an Australian leave and re-enter South Africa (90 days at a time without a visa) in a year, and do they need to be out of the country for a certain period of time before they re-enter?  I want to be in South Africa for as long as I can, however as an Australian without a visa I can only stay for 90 days at a time. What I would like to do is simply leave South Africa and go to another country in Africa for a few days, before returning with a new 90 day allowance.    Is this possible, or must I wait a certain period before re-entering South Africa/is there a limit to the amount of times I can do this in one year? SSMS wont give up file associations