Mac FAQ

Frequently Asked Questions about POV-Ray Mac

• Why does POV-Ray crash when opening a file in Mac OS X 10.2?
• Why is rendering on the Mac so slow?
• What is the "memory cache" in POV-Ray Mac 3.1g.r1 PPC?
• Why do I get the error "Could not find file colors.inc"?
• Why doesn't the download of the Appearance Manager work?
• Why doesn't the Appearance Manager I downloaded work with Mac OS 8.0?
• Why is there so much disk activity during rendering?
• StuffIt Expander says the archive is damaged!
• When starting POV-Ray I get the error that some library cannot be found, where can I get that library?
• Why will you drop support for 68K based Macintosh models?
• What's new in POV-Ray 3.1
• What's about POV-Ray and the G4 Velocity Engine (AltiVec)
• Does POV-Ray support multi-processor Macs?
• When will POV-Ray Mac support Mac OS X?

POV-Ray 3.5 for Mac OS Buid 170 and 173 problems with Mac OS X 10.2

Due to changes introduced late in Mac OS X 10.2 opening files via the File:Open menu command and dialog box is not possible. Mac OS X will terminate POV-Ray. As you may know, POV-Ray works flawlessly under Mac OS X 10.1.5 as well as Mac OS 8/9. The behavior in Mac OS X 10.2 appears to be a bug in this particular version of Mac OS X. We have contacted Apple to find out whether there is a workaround we can implement in POV-Ray or whether this requires a bugfix in Mac OS X provided by Apple.

For the time being you can open files via the Finder as usual.

You can also opening files by adding them to the Render Queue and starting the render.

If neither of these options is acceptable, you may also configure Mac OS X to start POV-Ray 3.5 in the classic environment. The Mac OS X help system provides details how to do this via the Get Info dialog.

The only way you cannot open files is via the File:Open menu command or Apple-O key combination (these two are equivalent).

All other functions of POV-Ray 3.5 for Mac OS should work with Mac OS X 10.2 without problems.

We apologize for the inconvenience!

Why is rendering on the Mac so slow?

This is the most frequently asked question. If you compared POV-Ray Mac 3.1 speed to a Windows or Linux version you have likely found the 15% or higher speed of these versions compared to the Mac version.

There are several reasons why this might be the case.

• You had the rendered image preview on. The preview of the Mac version is much slower compared to other platforms because of the high abstraction of Mac programming interface from the hardware. We simply cannot directly draw to the screen which would be much faster but less compatible. Another reason is that the Windows version, for example updates its preview once per line, not once per pixel which gives it an additional speedup.
• You are running lots of background applications or virtual memory. Even in Mac OS 8.5 virtual memory can cause 10% or more slowdown, especially for applications like POV-Ray which require a lot of memory. File sharing contributes to this another 10% or so.
• You did not set the Application Friendliness high enough. You find this setting in the Preferences dialog General pane. Set it up to "Tyrannical" and POV-Ray will run much faster at the cost of other applications running in the background.
• If you are running Linux on your Mac and compared the speed you wil also find some significant speed differences. Most of them are due to the completely different nature of the two operating systems. While Linux uses preemtive multi-tasking, the Mac OS still relies on cooperative multi-tasking which in most cases makes it run slower.
• You read some Mac magazine or internet publication and they claim for example a G3 with 300 MHz would outperform a Pentium II with 300 MHz by the factor of two or even more. Well, in some cases you may get such a difference, but this does not apply to all applications. As a matter of fact (I am sorry, but this is true), the PowerPC G3 is not much faster at all compared to a Pentium II with the same clock frequency. A industry wide accepted and much more objective benchmark is the SPECMark. Another very good resource (with industry wide accepted reputation) for information on processors in general is the Microprocessor Report. You find an interesting article about the PowerPC G4 there, too.

What is the "memory cache" in POV-Ray Mac 3.1g.r1 and 3.1g.r2 PPC?

After analysing the POV-Ray core code (which does the rendering) Eduard found a long time ago that one major reason for the slow PPC version is memory allocation. POV-Ray needs lots of small blocks of memory, but the Mac memory system is not optimised for this. The "memory cache" works around this problem by allocating lots of small blocks at once and then giving them to POV-Ray as it needs them. What exactly is going on inside POV-Ray is hard to explain and even harder to predict. That is why there is no general advise how to set the "memory cache" size. In most scenes the default normal setting will give a significant speedup with reasonable wasting of memory. If you are rendering a complex scene, using media, or radiosity this default setting may still not give optimal results. To help you to optimise the setting for your needs, memory cache statistics will be displayed together with the other render statistics. Usually the cache efficiency will be stable for different image sizes, so you can tune the cache before rendering a scene.

Here is a short overview of the general results (individual results may vary significantly!!!):

Note: Due to memory "wasted" by the cache during rendering (it will available after rendering, of course), you may need to increase the application memory size a bit to render scenes that already used most of the available application memory in previous revisions of POV-Ray Mac 3.1.

Note: Due to a misunderstanding, from August 2nd 1999 to August 16th 1999 slightly different POV-Ray Mac 3.1g.r1 for PPC archives (both, full version and update) were available on mac.povray.org, ftp,povray.org and www.povray.org. You can find out if you have the correct archive by going to the Preferences dialog General pane. Next to the "Appliaction Friendliness" setting you should find the "Memory Cache" setting (the 68K archives don't have this feature!). If it isn't there, you have the wrong version. You should get the PPC update archive in the download area, it now contains the correct PPC version again. The version up from August 2nd to August 16th is significantly slower than this correct version!

Why do I get the error "Could not find file colors.inc"?

There are two possible reasons for this presuming that the file and the folder "Include" really exist. Both are little limitations resulting of the cross-platform nature of POV-Ray. We will do your best to eliminate them completely in one of the future versions.

• You have not set the include file search path in the preferences. You can check this in the preferences dialog Rendering tab. One of the two include file folders should list a path ending with ":POV-Ray 3:Include:". You can set the folder by clicking on the Set button next to it. For more details please read the Mac specific documentation in the documentation folder.
• The name of the volumewhere the include folder is located starts with a space or other non-ASCII character. Simply remove all leading spaces from the volume name or move POV-Ray to another volume without leading spaces. Then make sure to set include file folder to the new location.

Why doesn't the download of the Appearance Manager work?

The Appearance Manger is an Apple product. Unfortunately Apple requires a license fee to distribute it - and to pay a license fee to distribute it with a free product is not feasable. Therefore the link to the Appearance manager is a Apple site where you can download the US version of the Apparance Manager for free. The Apple servers run under a very high load and Apple makes sure items on the servers are not damaged. If the download stops or you get a corrupted file, try again at least once. If it happens again, contact the Apple webmasters, not us. They can surely help you.

Why doesn't the Appearance Manager I downloaded work with Mac OS 8.0?

Unfortunately Apple only provides the US version of the Appearance Manager for download. If you are running a Mac OS 8.0 version that is not localised to English or US English the System will load the localised Appearance Manager version on startup, not the (newer) US version of it. In this case there is one simple workaround: The update to Mac OS 8.1 is free. You order it for (the equivalent of) a few US dollars from your local Apple subsidary or download from the web. To get the update from the web go to the page of your local Apple subsidary. If you don't know your local Apple website, go to the Apple US website and search for your country.

If you don't want or cannot update to Mac OS 8.1, please contact us at mac-team@povray.org and we will see if we can work around this problem for you.

Why is there so much disk activity during rendering?

There are two possible reasons. The obvious one is that you have virtual memory enabled and because ray-tracing can consume a lot of memory the System runs out of physical memory and starts swapping memory to the harddisk.

The other possible reason is that you have the preview enabled. The preview creates an image buffer on the disk. You can set the image buffer size in memory by adjusting the slider "Image buffer cache rows" in the Preview tab of the Render Settings dialog. Note that this may increase the memory demands of POV-Ray rapidly depending on the preview image size. Also note that this will not eliminate the disk activity completely because the whole image buffer is still on disk, but also completely cahed in memory. We are aware of the fact that this is not the fastest solution and will improve it in a future version of POV-Ray.

StuffIt Expander says the archive is damaged!

POV-Ray 3.1g is compressed using StuffIt 5.0. You need at least StuffIt Expander 5.0 to unpack these archives. We strongly recomment using StuffIt Expander 5.1 (which works much better with non-US Mac OS versions).

When starting POV-Ray I get the error that some library cannot be found, where can I get that library?

The only library POV-Ray needs and that may not be in your System is AppearanceLib. Please read the manual if you get this message, it explains in detail where to get the Appearance Manager and this library.

If you get any the message that any other library, i.e. something like "athLib" is missing, you have either a corrupted download or a corrupted System. Try downloading POV-Ray again, if this does not work, try running Disk First Aid (included with Mac OS) to identify and repair any problems on your System volume. If this does not help, you may want to try to reinstall your System.

The POV-Ray Mac archives are known to be ok!

Why will you drop support for 68K based Macintosh models?

We are sorry that we can no longer support 68K Macs, but in order to test the software, we need a 68K Mac to debug and test on, and nobody on the Mac POV-Ray team has one. Of course, this latest version of POV-Ray (3.1g) should work OK for you forever. You do not need to upgrade the software.

Hopefully you can understand that we cannot support the 68K Macs any more. Eduard tried to keep 68k support as long as possible. This is work we do in our spare time, for free, and we can only do so much. The 68K version has now become a lower priority. Other things are much more important now. If we do not spend time working on the new Macs and new OS support, there will be thousands of people mad at us. On the other hand, 68K Macs have been out of production for over five years and the download statistics and the questionnaire results indicate a very low percentage of 68K Mac users left.

What's new in POV-Ray 3.1

Here is a list of the the main new features in the POV-Ray Mac 3.1:

• Tons of language enhancements, arrays, macros, local variables, media overhaul, file I/O, #undef, etc.
• Direct import of PICT files for image maps ('sys' image type.) With QuickTime 3, it also directly imports many other image files (Photoshop, IFF, PNG, TIFF, SGI, etc.!)
• Better animation support, now adheres to any .INI file settings for animation.
• Syntax coloring in editor (keywords & comments can be different colors.)
• Editor is drag-n-drop aware, better tab support, auto-indenting, less bugs (uses WASTE engine), handles huge text files.
• Scrollbars added to the Preview Window.
• Selection marquee in Preview Window for selective rendering.
• Alpha-channel transparency directly shown in Preview Window.
• Mac OS 8 Appearance-savvy windows and dialogs, Navigation Services too (preparing for MacOSX.)
• Direct QuickTime movie output.
• Beautifully illustrated POV.DOC self-reading reference/tutorial document.
• Questionaire application to help us gather your feedback, please send us your wishes!
• About the POV-Ray Mac OS Team

What's about POV-Ray and the G4 Velocity Engine (AltiVec)

A lot of users have seen the G4 (PPC 7400) demo by Steve Jobs. He showed how fast PhotoShop with special plug-ins for AltiVec can be. He also implied that G4 are much faster than PCs doing 3D graphics and a G4 would bring supercomputer power to you.

Well, as you may have noticed, Apple is much better in marketing their products than two years ago. If you look carefully, you will find that AltiVec is a great technology, but in most applications it will do little, if anything. FrameMaker or XPress for example won't see this speed gain, they don't deal with large graphics nor are they 3D games or a signal processing application.

Now, POV-Ray is a 3D application, but wait, there is another significant limitation! AltiVec uses single-precision floating-point numbers (there is no double-precision supported in the AltiVec architecture). By far the most floating-point code in POV-Ray uses (and needs) double-precision floating-point numbers. AltiVec (instructions) simply cannot be used to speed up those. So to make it short: AltiVec is good for a lot of things, but not high quality ray tracing.

However, there are other improvements in the G4s that will likely give you a speedup: First of all, double-precision floating-point multiplication is 25% faster now (this does not equal 25% higher render speed!). Other improvements like the higher memory bandwidth and cache management enhancements will also be beneficial. Together this will surely lead to a noticeable performance increase, especially for long renders (we will surely know details soon). It is just evolution, but nothing revolutionary to get extremely excited about.

You find much more objective and correct information at Motorola's PowerPC 7400 web page. The analysis above is based on the information provided by Motorola on their web page. There is a link to the Technical Summary of the PPC 7400 on that page. The summary also discusses the differences and improvements between the PPC 750 (G3) and PPC 7400 (G4) in great detail!

Anyway, of course we will explore ways to speed up POV-Ray on the G4! First we need to get our hands on a G4, and at least I (Thorsten) don't expect that to be the case until sometime next year :-)

Does POV-Ray support multi-processor Macs?

No, POV-Ray will not benefit from multiple processors.

It is also unlikely that POV-Ray will support multiple processors before POV-Ray version 4.0. Right now complex issues related to the multi-platform nature and age of the source code of POV-Ray make it impossible.

The only possible feature we may be able implement in one of the next releases of POV-Ray is the ability to do the rendering on one processor and allow the editor (and other applications) to run on the other processor.

When will POV-Ray Mac support Mac OS X?

The current version of POV-Ray, which is 3.1g will not support Mac OS X. You can of course run it using the Classic environment.

POV-Ray 3.5 will support Mac OS X and run as a Carbon application.

There will be two versions of POV-Ray 3.5 Mac, one for Carbon and one for Mac OS 8.1 and later. We will not support System 7.x configurations.

Further, a word to all those developers who now think about making the current POV-Ray Mac 3.1 source code carbon compatible: Do not waste your time! POV-Ray 3.5 will be a complete rewrite and support all the features we have been missing, like multiple open scene text editor windows and much more. You can read about it in the POV-Team Status Report.