POV-Ray

There are a number of problems with the Windows version of POV-Ray under Windows Vista. To resolve these, the setup program needs to be re-written and the location of internal files changed.

The Rect data type needs to be renamed to avoid a clash with a Mac OSX declaration. It was originally called Rectangle, but this clashed with a Windows declaration. Something more POV-specific should be used, e.g. PovRect.

Array.inc and subsurface.pov are in read only mode, they probably should have normal permissions.

Beta 32, compiled from source on Linux/Ubuntu, amd64.

The random “window display lock” is back.
(as the previous “solution” was to get no window display usable, that’s not so bad).

What is it: sometime, when the rendering window is activated, povray just draw the frame
of the window, paint it black, does not display anything else but seems to perform the
rendering in separate threads. Whenever the mouse move over the frame of the window, it
unlock the updating process and big parts of the rendered image pop up.

What it is not fine: if you do not move the mouse over the window, povray will just stall.
This is more a problem for animation rendering, as getting the display might be a wanted
bonus to monitor the rendering images, and you just fall into that lock: your expected
night rendering could very well be suspended on the first frame.
Moreover, the “move the mouse over” works only for local display. In previous beta (not
yet checked with 32), with a remote display, there was no way to unlock povray.

Reported for freebsd 7.2 (current production version, true for previous version, unknown for 8.0 in beta now)

freebsd does not provide CLOCK_PROCESS_CPUTIME_ID
(even if CLOCK... is posix).

As a consequence, compilation of the unix-source is currently not possible for freebsd target.

Might be a simple selection for Change 4356 ?
(assuming a relevant test in ./configure)
(getrusage() seems available on freebsd, but does it provide the pieces of information needed, I do not know that code good enough to assert that)

Scenes starting with the incorrect syntax

version 3.7;

do not raise an error, instead they render a black screen with an empty scene warning.
#version should fail with an error when the # is missing.

The function of the “Debug_File=” .ini option has changed from 3.6 to 3.7.37a.
In 3.6, when rendering multiple frames, a debug file would be created that then appended the debug lines for each frame into the file. It was therefore able to have debug data that identified what parameters were used in which frame in case a frame did not have the desired effect.

In 3.7.37a, the debug file does not perform this function. Instead it creates a new debug file (overwriting the prior) with each new frame. Therefore the debug data is only useful for the final frame (or wherever the render was halted). This is useful for a single frame render or for identifying a fault within a series of frames (because only the last one will remain) but it is not useful for many frames that render successfully.

This problem does not cause any rendering errors or other defects. The debug file specified will only contain the debug data for the last frame rendered.

Per discussion in the forum it was unknown if this was a bug or “feature”. At this time it is causing me a problem so I am submitting the bug. No related bugs were found searching for “output” or “debug” in any status.

Operating System in use is Windows XP. I cannot test 3.7.37a in additional OSes, but it does not seem like it would be OS-specific.

20 library paths is a bit small given the sheer number of include files I’ve collected over the years. An increase in the number, and/or the ability to include wildcards in the search path, would be great.

The documentation assumes that INI files (as well as the command line!) are parsed and processed instantly. This no longer holds true for POV-Ray 3.7, where parsing INI files (and the command line) and processing it are separate operations that occur at different times. As such, one consequence is that INI file options only take effect after reading the whole INI file, and possibly later.

As such, documentation statements such as <http://www.povray.org/documentation/view/3.6.1/222/>
“Note: that these options take effect immediately when specified. Obviously any error or warning messages that might occur before the option is read will not be affected.”

Are no longer correct. It needs to be explained that options only take effect after the INI file has been read. An error in the INi file causes other options _not_ to take effect because reading of the INi file is aborted prematurely.

source/png_pov.cpp included in povray-3.6.1 contains calls to an internal function of libpng (png_write_finish_row) which was removed from the public interface quite a while ago, so linking fails.

Also, in the 1.4 releases of libpng, the info_struct “trans” member was renamed to trans_alpha. This causes a compilation error in the same file.

A suggestion for the solution:
a) remove the png_write_finish_row prototype and function call
b) add something like:
#if PNG_LIBPNG_VER < 10400
#define trans_alpha trans
#endif
and change
cmap[index].Transmit = 255 - r_info_ptr→trans[index];
to
cmap[index].Transmit = 255 - r_info_ptr→trans_alpha[index];
(two occurrences).

Windows allows you to associate programs with file extensions using the “Open with” file manager right-click menu extension.

I’m running Windows 7 64bit, and installed the 64 bit versions of 3.6.2 and the beta appropriately.

A couple of problems that I haven’t tested very thoroughly:

1. If you have both POV 3.6.2 and the beta installed at the same time, you can no longer using this dialog change the association to the beta once it has been created for 3.6.2. There’s no error or anything; it just opens the file inside 3.6.2 instead. Maybe because both versions appear as “POV-Ray for Windows” to this dialog? Would adding the version number to the name fix things? Anything I can do on my end of things to resolve this?

2. In POV-Ray 3.6.2, I can use this dialog to open *.inc, *.txt and other files in POV-Ray, but only if POV-Ray isn’t already running. If POV-Ray is already running I get an “Only /EDIT and /RENDER may be passed to previous instance” error. Files with the *.pov extension open properly regardless, without any error. I am unable to test this in the beta at the moment due to the first problem unfortunately. Could someone please test this with the beta and confirm whether the behavior also exists?

3. With the POV-Ray 3.7 beta, entering the following command in the command prompt results in the same error:

   "C:\Program Files\POV-Ray for Windows v3.7\bin\pvengine64.exe" "D:\Working\Povray\GearHead\LoadingScreen\btr_maanji.pov"

If I change it to the following it works however:

   "C:\Program Files\POV-Ray for Windows v3.7\bin\pvengine64.exe" /EDIT "D:\Working\Povray\GearHead\LoadingScreen\btr_maanji.pov"

Is this error/behavior really necessary? Would it be OK to instead change the behavior when the /EDIT flag is omitted in the
command-line such that the file is opened in the editor by default, without throwing an error?

While testing if the png support was working, I tried 3.7.0rc3 on NetBSD-5.99.45/amd64, and had the following problems:

1. lseek64 (used in source/base/image/image.cpp) is not portable, and not necessary on NetBSD (off_t there is large-file-safe)
2. unix/Makefile.am doesn’t add -lboost_thread to povray_LDADD, which breaks linking the executable.
3. vfe/unix/platformbase.cpp uses CLOCK_THREAD_CPUTIME_ID, which is not provided on NetBSD (I hacked around it by defining the symbol to “0”, but that’s of course not a correct fix).
4. vfe/unix/platformbase.cpp uses CLOCK_PROCESS_CPUTIME_ID, which is not provided on NetBSD – it’s called CLOCK_REALTIME like on FreeBSD, so we could just add defined(NetBSD) to the FreeBSD case, except for point 3.
5. vfe/unix/vfeplatform.cpp uses WEXITSTATUS. For this, sys/wait.h should be included. The obvious fix is
#ifdef HAVE_SYS_WAIT_H
# include <sys/wait.h>
#endif
but this also needs a check in the configure script.

Fixing all this, I get it to build, but core dump when run against the demo file from http://www.csb.yale.edu/userguides/graphics/povray/demo.pov.html.
Backtrace is
Program terminated with signal 11, Segmentation fault.
#0 0x00000000004ac479 in boost::gregorian::date::date ()
(gdb) bt
#0 0x00000000004ac479 in boost::gregorian::date::date ()
#1 0x00000000004d29f7 in boost::gregorian::date::date ()
#2 0x0000000000479a85 in std::vector<std::string, std::allocator<std::string> >::operator= ()
#3 0×0000000000461570 in std::vector<std::string, std::allocator<std::string> >::operator= ()
#4 0x00000000004656c7 in std::vector<std::string, std::allocator<std::string> >::operator= ()
#5 0x00000000005efc9f in Imf::TypedAttribute<std::string>::typeName ()
#6 0x00000000005fd890 in Imf::TypedAttribute<std::string>::typeName ()
#7 0x00000000005fe5d8 in Imf::TypedAttribute<std::string>::typeName ()
#8 0x000000000045d6dc in std::vector<std::string, std::allocator<std::string> >::operator= ()
#9 0x00007f7ffd80d9cf in thread_proxy ()

from /usr/pkg/lib/libboost_thread.so.1.45.0

#10 0x00007f7ffd00b24e in pthreadcreate_tramp (cookie=<value optimized out>)
at /archive/cvs/src/lib/libpthread/pthread.c:473
#11 0x00007f7ff8871780 in _lwp_park50 () from /usr/lib/libc.so.12

Please advise on how to proceed.

In vfe/unix/unixoptions.cpp, -V is defined as a synonym for -​-version, overriding its general meaning of Verbose=off.

REcently I installed POV-Ray tracing software in my mac OS X version 10.6.8. When I run the software its displaying a fatal error occured and the error number is -43. I’m new to POV-Ray...pls help me guys...

Keyword Completion does not work for several names.
I miss it for animation related names like frame_number or final_frame.

Typing “fram{TAB}” just inserts a TAB character after “fram” instead of completing it to frame_number.

Independently of that bug, typing {TAB} repeatedly does not cycle through possible names:
“fr{TAB}” gives “frequency” and “fresnel” and that’s all.

In version 3.6 it worked well.

My system is Windows 7 64bit and PovRay is 3.7.0.RC3.msvc9.win64

Originally resolved in https://bugs.gentoo.org/show_bug.cgi?id=425450.
Attached is a patch with Gentoo-specific code removed.

There are two parts in this issue:

• The newer boost library requires downstream users to explicitly link to the boost system library (-lboost_system).
• The newer boost library replaced TIME_UTC with TIME_UTC_, because glibc added TIME_UTC.

Beta 32 is failing to render a mesh2 smoothly on 64-bit XP - output shows flat triangles rather than smoothed triangles.
Issue is not present in 32-bit build.

Reported in http://news.povray.org/49e51489%241%40news.povray.org. Demo image rendered using standard chessmesh scene.

Using a facet pattern in a normal map results in a unspecified error in Evaluate_TPat at the render stage.
This probably should be caught at parse time to give a more descriptive error and a line number.

Example:

sphere {
  0, 1
  texture{
    pigment{rgb <1,1,1>}   
    normal {
      facets
      normal_map {
         [0 bumps ]
         [0.5 facets ]
         [1 bumps ]
      }
    } 
  }
}

Files of exactly 4k length can cause a full crash exception when opened.

Overlapping partially transparent objects can result in speckled shadows.
Rays shouldn’t leak through the coincident areas, they should return one
of the two textures. This was correct in 3.6.

#declare testmat = material { texture {
      pigment {color <1,0,0> transmit 0.5}
}};

camera { location  <1.0, 2.0, -4.0>
   direction 1.5*z
   right     x*image_width/image_height
   look_at   <1.0, -0.2,  0.0>
   angle 30 }

light_source {<-10, 10, -5> color rgb <1, 1, 1>}

plane {y,-1 pigment{rgb <1,1,1>}}

union {
   sphere {<0.0,0,0>,0.5 material{testmat}}
   sphere {<0.1,0,0>,0.5 material{testmat}}
   sphere {<0.2,0,0>,0.5 material{testmat}}
   sphere {<0.3,0,0>,0.5 material{testmat}}
   sphere {<0.4,0,0>,0.5 material{testmat}}
   sphere {<0.5,0,0>,0.5 material{testmat}}
}

Using trace or inside with a julia fractal causes a crash.

#declare Test = julia_fractal {
  <-0.083,0.0,-0.83,-0.025>
  quaternion
  cube 
  max_iteration 8
  precision 20
};
#declare Norm = <0,0,0>;
#declare Hit = trace(Test,<0,0,-10>,z,Norm);
#declare Center = inside(Test,<0,0,0>); 

Reflective texture maps can cause a stack overflow crash.

sphere{0,1
  texture{
   bozo
   texture_map{
    [0 pigment{rgb 0}]
    [1 pigment{rgb 0} finish{reflection 1}]
   }
  }
}

In unix distribution these scripts

• allscene.sh
• allanim.sh
• porfolio.sh

have the variable VERSION set to 3.6

3.6x only bug with easy/known fix. Error message: “Identifier expected, incomplete function call or spline call found instead.” caused by token counter variable using the wrong special value. The symptom occurs when using a lot of splines. See this thread for details.

(I am using a self-compiled special build because I use a lot of splines in 3.6 but would rather use an official 3.6)

Linux beta 32, 64bits, compiled from sources.

povray -w800 -h600 +a0.3 +kfi1 +kff78
-L/usr/local/share/povray-3.7/scenes/incdemo
-Ii_internal.pov +WT5 +R4 +AM1 +MB1

Important issue: +WT5 +MB1

Seems Fine for +WT1 +MB1
Also fine for +WT5 +MB9

The intersection with the containing box displays some two-shades of grey
random checkered patterns.
Size of square looks like size of renderering thread. Position too.

Impacted frames (of 78):
01, 02, 03, 30, 48, 74, 76.

Function use in image maps is broken.

The following should result in a white and green checkered unit square, but is transparent.

camera {
   location  <0.0, 0.5, -4.0>
   direction 1.5*z
   right     x*image_width/image_height
   look_at   <0.0, 0.0,  0.0>
}

background {rgb <1,1,1>}

light_source {
  <-30, 10, -30>           
  color rgb <1, 1, 1> 
}

plane {y,-1 pigment{checker rgb <1,0,0> rgb <1,0.5,0.5> }}

plane {y,-0.99 
 pigment {
  image_map { 
   function 10,10 { 
    pigment {checker rgb <0,1,0>, rgb <1,1,1> scale 0.1}
   }
   once 
  }
  rotate <90,0,0>
 }
}

The parser is failing to read the .tiff file extension from the input string...

bump_map { tiff "earth03_hf2.tiff" }

Results in file not found, but

bump_map { tiff "earth03_hf2" }

will find the file. It might be that it’s not a three character extension?

The parser is missing extra period characters when it parses a float as a vector component.

#local sample = <0.0.0.1,0,0>;

Doesn’t generate an error, but should.

After a recent update on the POV-Wiki the GuMax skin doesn’t recognize MediaWiki:Common.css entries.

The following files were garbled in changelist #4648 by stripping all line terminators, making the files unusable:

• .../scenes/advanced/cats/cattext.inc
• .../scenes/animations/life/blink4.inc
• .../scenes/animations/life/walker.inc

Line terminators of these files were already problematic in previous versions of the file, having been CR-only.

The following files changed with #4648 should be reviewed closely as well, as they were previously CR-only, too, and at least some of them exhibit some peculiarities regarding line and/or file terminators:

• .../scenes/animations/pentmap/pentmap.ini
• .../scenes/animations/pentmap/pentmap.pov
• .../scenes/animations/slinky/slnk.ini
• .../scenes/incdemo/metals/metals.doc
• .../scenes/incdemo/stones/stones.doc
• .../scenes/incdemo/woods/morewood.doc
• .../scenes/incdemo/woods/woods.doc
• .../scenes/textures/pigments/skies/skies.doc

In POV-ray 3.7 beta 33 under Windows XP, the editor’s MRU list incorrectly handles files that have a comma in the pathname. Only the part of the name before the comma appears on the MRU list, but the rest of the name is left off.
Consequently, the file cannot be reopened via the MRU list. The file is also not reopened on launch if pov was closed with the file open. This also occurs in 3.6.1, I haven’t tried it under 3.6.2 yet.

Interestingly enough, a quick peek in the registry shows that both 3.6 and 3.7
are saving the entire path name correctly under HKEY_CURRENT_USER\Software\POV-Ray\v3.6\POV-Edit\Recent (or \v3.7\POV-Edit\Recent).

This seems to be limited strictly to the editor’s MRU list. The file can still be opened normally using the open dialog box. Calling POV-ray from the command line and using a file or path name with commas in it works correctly. Included files with commas in the path work correctly, and the Tools→Edit last rendered file/View last rendered file work correctly also.

To duplicate, save a file with a comma in the pathname (either in the directory
name or the filename itself). Close the file, then attempt to reopen it using the MRU list in the file menu.

Bounding box computation for CSG intersection appears to be broken when one member is an arbitrarily transformed plane.

POV-Ray 3.6.2 has the same problem (can’t test for 3.6.1).

// +W640 +H480 +MB1

#include "transforms.inc"

camera {
  location  <-0.2, 0.5, -4.0>
  direction 1.5*z
  right     x*image_width/image_height
  look_at   <0.0, 0.0,  0.0>
}

sky_sphere {
  pigment {
    gradient y
    color_map {
      [0.0 rgb <0.6,0.7,1.0>]
      [0.7 rgb <0.0,0.1,0.8>]
    }
  }
}

light_source {
  <0, 0, 0>            // light's position (translated below)
  color rgb <1, 1, 1>  // light's color
  translate <-30, 30, -30>
}

plane {
  y, -1
  pigment { color rgb <0.7,0.5,0.3> }
}

intersection {
  sphere {
    0.0, 1 }
  plane { -x, 0 transform { Shear_Trans(x,y+x*0.3,z) } }
  texture {
    pigment {
      radial
      frequency 8
      color_map {
        [0.00 color rgb <1.0,0.4,0.2> ]
        [0.33 color rgb <0.2,0.4,1.0> ]
        [0.66 color rgb <0.4,1.0,0.2> ]
        [1.00 color rgb <1.0,0.4,0.2> ]
      }
    }
    finish{
      specular 0.6
    }
  }
  rotate -y*5
}

The following (bogus) SDL code causes POV-Ray 3.7 beta to crash hard with an access violation:

#include "fubar.inc"
Bar(42)
#macro FooBar() #end

//fubar.inc
#macro Foo(Fnord) #end
#macro Bar(Ignord) Foo(23 #end

It appears that reflective bounces from blobs are
not incrementing the trace level, causing self-
reflecting hall of mirror portions to stall renders.

I have installed POV-Ray 3.7 beta 34 on Windows 7
The setting ‘Output_Alpha=on’ doesn’t work as documented. With this setting the Background appear black and the scene is transparent.

Check with this Code:

camera {
   location  <3, 3, -3>
   direction <0, 0, 2.9>
   look_at   <0, 0, 0>
   right 1.0*x
}
light_source { < 3, 3, -3> color red 1 green 1 blue 1 }
sphere 
{
   <0,0,0> 0.8
   pigment {color rgb<1,1,0>}
   finish
   {
      ambient 0.2
      diffuse 0.8
   }
}

and with this ini file:

Input_File_Name=C:\Users\dfv_rei1\AppData\Local\Temp\Cuadrigula\PreviewObject.pov
Output_File_Name=C:\Users\dfv_rei1\AppData\Local\Temp\Cuadrigula\PreviewObject.tga
Output_File_Type=t
Output_Alpha=on
Bits_Per_Color=24
+W121 +H121
+a0.3
+q11
+a

The attached TIFF file was created with IC using compression. When used in an image_map, POV-Ray 3.7.0.beta.34 on Windows XP x64 renders the image all transparent, while POV-Ray 3.6.2 renders the file fine. The same effect can be seen with LZW-compressed TIFF files created with Adobe Photoshop 6.0.

Uncompressed TIFF files created with either IC or Photoshop render fine in both versions of POV-Ray.

Stepping through the code of POV-Ray 3.7.0 shows that the same code path is taken regardless of compression, but the libtiff library returns different alpha channel values, indicating a problem in that library. POV-Ray 3.7 still uses libtiff 3.6.1, whereas the POV-Ray 3.6 branch has been updated to libtiff 3.8.2, which according to the change history includes a few alpha-related changes.

The following scene, showing an almost cylindrical cone floating above a plane, renders fine in POV 3.6.2, but is obviously broken in 3.7.0.beta.34:

camera {
  right     x
  up        y*image_height/image_width
  location  <80,50,40>
  look_at   <0,0,0>
}

light_source { <500,500,500> color rgb 1 }

cone {
  <0,0,30>, 11.303000, <0,0,-30>, 11.302999
  texture { pigment { color rgb 1 } }
}

plane { y, -20 texture { pigment { color rgb 0.3 } } }

The error occurs even with the -MB option, indicating that the problem has nothing to do with bounding, but is in the cone intersection testing code.

Source code inspection during examination of issues with the scene published at http://povray.sitewww.ch/?p=177 show the following issues with current (beta.34) implementation of dispersion in POV-Ray 3.7:

• The same adjustment to the IOR that is applied at the very first dispersion interface is erroneously applied to all subsequent interfaces.

• As an exception, dispersion adjustment is erroneously not applied to any interface defined by the surface of a non-dispersing object embedded into a dispersing object.

While this still allows to use dispersion for artistic effect, it is neither physically realistic, nor does it match 3.6 behavior.

In the following scene, the mesh object will always cast a fully-opaque shadow, even if the image has an alpha channel:

camera {
  location  <0.5, 1.0, -1.0>
  look_at   <0.5, 0.0,  0.5>
}

light_source { <0, 30, 0> color rgb 1 }

mesh {
    triangle { <0,0,0>, <1,0,0>, <1,0,1> uv_vectors <0,0>, <1,0>, <1,1> }
    triangle { <0,0,0>, <1,0,1>, <0,0,1> uv_vectors <0,0>, <1,1>, <0,1> }
    texture { pigment { uv_mapping image_map {png "FOOBAR.png"} } }
}

plane { y, -0.1 pigment { color rgb 1 } }

The following modification to the texture will give the expected results:

    texture { uv_mapping pigment { image_map {png "FOOBAR.png"} } }

The problem can be observed with both POV-Ray 3.7 (tested with beta.34), as well as 3.6 (tested with 3.6.2).

Reported by cshake + pov @ gmail . com in p.beta-test, 14th december 2009

I wrote a simple script to convert fractint color maps to povray color_maps so I could use ApoMap to make nice fractal colors for pov, but I ran into
“Parse Error: Blend_Map too long.” The map has entries from 0/255 up to 255/255 (inclusive). I looked up the documentation which says that color_maps can have from 2 to 256 entries, and this is exactly 256 entries.
I’m posting this in beta-test because I assume that the documentation is correct for v3.6, and that a previous version can handle 256 entries.

Cone is not on good place when first base point is lower then end cap point.
Example:

cone { <0, 0, 0>, 2, <0, 1, 0>, 1 } - good
cone { <0, 0, 0>, 1, <0, 1, 0>, 2 } - bad

This is on 3.7 beta 35 version.

File output code for virtually all file formats performs gamma correction on unclipped color values, which leads to issues when color values happen to be negative for some reason and gamma does not happen to be an integer value such as 1.0 or 2.0. As a consequence, subsequent steps (clipping and converting to integer) apparently produce compiler-dependent results. Compiled with Microsift or Intel compilers, POV-Ray seems to write zero brightness in such cases, while compiled with g++ 4.4 (and possibly other compilers) it seems to write full brightness instead.

(See thread news://news.povray.org:119/4ba819f6@news.povray.org for examples.)

The proper solution should be to apply gamma correction after clipping.

When choosing PPM output with a bit depth other than 8 bits per color channel (e.g. +FP16), POV-Ray messes up the colors (see thread news://news.povray.org:119/4babb48f$1@news.povray.org)

The following code is erroneously accepted by POV-Ray (tested with 3.7.0.beta.36):

pigment{
  slope { x }
  checker
}

The result is a checker pattern.

Apparently there is an EXIT statement missing in the slope-pattern parsing code in parstxtr.cpp.

This item may need to be merged with item FS#81. This is another sphere sweep bug, though they are of different spline types.

The code is

#include "colors.inc"

camera {
  location  <0, 0.0, -4.0>
  direction 1.5*z
  right     x*image_width/image_height
  look_at   <0.0, 0.0,  0.0>
}

light_source {
  <0, 0, 0>            // light's position (translated below)
  color rgb <1, 1, 1>  // light's color
  translate <-30, 30, -30>
}


#declare i_start = 0;
#declare i_stop = 3;
#declare i_step = 0.05;
#declare i_inc = i_start;
sphere_sweep {
  linear_spline                 // linear curve

  (i_stop - i_start)/i_step + 1,    // number of specified sphere positions
#while(i_inc<=i_stop)
  
  #declare y_coor = 0.23*sin(7.1*i_inc);
  <i_inc, y_coor, 0>, 0.05
        #declare i_inc = i_inc + i_step;
 
        
#end

pigment{color Orange}

}

The following scene shows how photons are “boosted” by pass_through objects; removing one of the boxes will reduce the effect; the effect can be seen with 3.6 as well as current betas:

global_settings {
  max_trace_level 10 // makes a difference!
  photons { spacing 0.02 }
}

camera {
  right x*image_width/image_height
  location  <0,2.6,-10>
  look_at   <0,0.75,0>
}

light_source {
  <500,500,150>
  color rgb 1.3
  photons {
    refraction on
    reflection on
  }
}

sky_sphere {
  pigment {
    gradient y
    color_map {
      [0.0 rgb <0.6,0.7,1.0>]
      [0.7 rgb <0.0,0.1,0.8>]
    }
  }
}

plane {
  y, 0
  texture { pigment { color rgb <1.0, 0.8, 0.6> } }
}

#declare M_Glass=
material {
  texture {
    pigment {rgbt 1}
    finish {
      ambient 0.0
      diffuse 0.05
      specular 0.6
      roughness 0.005
      reflection { 0.1, 1.0 fresnel on }
      conserve_energy
    }
  }
  interior {
    ior 1.5
    fade_power 1001
    fade_distance 0.9
    fade_color <0.5,0.8,0.6>
  }
}


sphere {
  <1.1,1,-1.3>, 1
  material { M_Glass }
  photons {
    target 1.0
    refraction on
    reflection on
  }
}

cylinder {
  <-1.2,0.01,0.8>, <-1.2,2.5,0.8>, 1
  material { M_Glass }
  photons {  // photon block for an object
    target 1.0
    refraction on
    reflection on
  }
}

box {
  <2.4,0,-2.3>, <2.6,4,-0.3>
  material { M_Glass }
  photons { pass_through }
}

box {
  <2.9,0,-2.3>, <3.1,4,-0.3>
  material { M_Glass }
  photons { pass_through }
}

I’ve tried to model this setup:
http://kschwebke.webng.com/povray/ior-interfaces/drawing.png with the following SDL:
http://kschwebke.webng.com/povray/ior-interfaces/rs2.pov.txt

A small overlap between the two transparent solids is needed, because a gap
would lead to total reflection. The camera in the test scene looks in the
direction of the ray in the setup drawing. The setup is surrounded with angular
markers, so one can easily read the final resulting looking angle.

POV-Ray 3.6.1 renders the expected result (~53° in the center of the screen):
http://kschwebke.webng.com/povray/ior-interfaces/rs2-35.jpeg

POV-Ray 3.7.0b35a (compiled Unix source) renders a different
(and in my opinion wrong) angle (~67°), however – for the very same scene file:
http://kschwebke.webng.com/povray/ior-interfaces/rs2-37b35a.jpeg

I’ve started a discussion about this issue in povray.beta-test: http://news.povray.org/povray.beta-test/thread/%3Cweb.4bba4677730ab9f3e8c084b40%40news.povray.org%3E/

All linked documents are also attached.

The code to attenuate transmitted photons according to surface texture was apparently duplicated during refactoring of the source code for version 3.7. Behavior has changed from 3.6 to 3.7 (beta.36) accordingly, as can be demonstrated with the following scene:

global_settings {
  assumed_gamma 1.0
  max_trace_level 10
  photons { spacing 0.02 }
}

camera {
  right x*image_width/image_height
  location  <0,2.6,-10>
  look_at   <0,0.75,0>
}

light_source {
  <500,300,150>
  color rgb 1.3
  photons {
    refraction on
    reflection on
  }
}

sky_sphere {
  pigment {
    gradient y
    color_map {
      [0.0 rgb <0.6,0.7,1.0>]
      [0.7 rgb <0.0,0.1,0.8>]
    }
  }
}

plane {
  y, 0
  texture { pigment { color rgb <1.0, 0.8, 0.6> } }
}

#declare M_Glass=
material {
  texture {
    pigment {rgbt 1}
    finish {
      ambient 0.0
      diffuse 0.05
      specular 0.6
      roughness 0.005
      reflection { 0.1, 1.0 fresnel on }
      conserve_energy
    }
  }
  interior {
    ior 1.5
    fade_power 1001
    fade_distance 0.9
    fade_color <0.5,0.8,0.6>
  }
}

#declare M_PseudoGlass2=
material {
  texture {
    pigment {rgbf <0.8,0.2,0.2,0.8>}
    finish {
      ambient 0.0
      diffuse 0.05
      specular 0.6
      roughness 0.005
      reflection { 0.1, 1.0 fresnel on }
      conserve_energy
    }
  }
  interior {
    ior 1.0
  }
}

sphere {
  <1.1,1,-1.3>, 1
  material { M_Glass }
  photons {
    target 1.0
    refraction on
    reflection on
  }
}

box {
  <2.4,0,-2.3>, <2.6,4,0.3>
  material { M_PseudoGlass2 }
  photons { target 1.0 refraction on reflection on }
}

When using cutaway_textures the differenced part traces black. Simple scene file attached.

The #switch directive isn’t parsing correctly. In the following construct NO warning or error is generated:

#switch (RF)

case (0)
	rotate z*355
#break
case (144)
	rotate z*7.5
#break
case (216)
	rotate z*5
#break

#end

RF is a variable passed to the macro in which this construct resides. The first ‘case’ action IS executed, but none of the others are on successive calls to the macro. If I properly add ‘#’ to the second case the 1st and 2nd condition are executed but not the last. If ‘#’ is REMOVED from any of the break directives an error is generated and parsing halts.