POV-Ray : Newsgroups : povray.beta-test : transparent blob bug Server Time
2 Jul 2024 10:57:32 EDT (-0400)
  transparent blob bug (Message 1 to 4 of 4)  
From: David Burnett
Subject: transparent blob bug
Date: 4 Jan 2010 14:03:14
Message: <4b423b72@news.povray.org>
I appear to have hit a transparent blob bug.

I initially though the bug was related to task 53, which it is noted is 
fixed in the latest beta but the scene I trying to render will still not 
render a specific part of the scene given reasonable time, i.e. 18 hours 
just for one specific square (bucket?), when in MacMegaPov 1.2.1 the 
whole scene renders in 8 hours. Using non transparent spheres in the 
blob it renders in seconds in either version.

The scene is rather large, well for me, with over 5000 spheres 
contributing to the blob so I know its not ideal for debugging other 
than the 'start it off in, a debugger and wait a day and see where its 
at and them start debugging' style.

I'm currently rendering it again, in order to locate the spot it stops 
again and seeing if a partial render of that area with allow for a 
quicker run to the point it stops.

The system specs are...
2.0Ghz CoreDuo 2Gb iMac, running OSX 10.6.2

The version of POV-ray I'm running is the Yvo's 3.7.0.beta.35 Universal 
build for Mac OS 10.5 or later.


Persistence of Vision(tm) Ray Tracer Version 3.7.0.beta.35
Compiler: gcc 4.2.1 (Apple Inc. build 5646) (dot 1)
This is an unofficial version compiled by:


The scene can be downloaded from 
http://planetgenesis.sf.net/blob_bug.zip and is 133kb

The ini file saved from the beta is....

Antialias_Depth=3
Antialias=On
Antialias_Threshold=0.3
Bits_Per_Color=8
Bounding=On
Bounding_Threshold=10
Continue_Trace=On
Create_Ini="/Users/vargol/Source/Releases/StructureSynth-v1.0.0/output.ini"
Display=On
End_Column=1000
End_Row=1000
Height=1000
Input_File_Name="/Users/vargol/Source/Releases/StructureSynth-v1.0.0/output.pov"
Jitter_Amount=1
Jitter=On
Library_Path="/Users/vargol/Source/Releases/StructureSynth-v1.0.0/"
Library_Path="/Users/vargol/Apps/POV-Ray 3.6/include/"
Output_Alpha=On
Output_File_Name="/Users/vargol/Source/Releases/StructureSynth-v1.0.0/output.png"
Output_File_Type=n
Output_To_File=On
Quality=9
Remove_Bounds=On
Render_Block_Size=32
Sampling_Method=2
Split_Unions=On
Start_Column=1
Start_Row=1
Version=3.6
Width=1000
Work_Threads=2


Dave


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From: David Burnett
Subject: Re: transparent blob bug
Date: 12 Jan 2010 15:56:01
Message: <4b4ce1e1$1@news.povray.org>
David Burnett wrote:
> I appear to have hit a transparent blob bug.
> 
I've looked into this a little bit more...
I rendered the full scene as a 10 x  10 image and got the following 
statistics. The obvious issue is that in the beta Max Level is 1/5
compared to 5/5 for MMP. Is the bug http://bugs.povray.org/task/53 
really fixed or have I hot a similar bug ?


MacMegaPov

Scene Statistics
   Finite objects:            1
   Infinite objects:          1
   Light sources:             3
   Total:                     5
Render Statistics
Image Resolution 10 x 10
----------------------------------------------------------------------------
Pixels:              100   Samples:            1898   Smpls/Pxl: 18.98
Rays:            1665597   Saved:                 0   Max Level: 5/5
----------------------------------------------------------------------------
Ray->Shape Intersection          Tests       Succeeded  Percentage
----------------------------------------------------------------------------
Blob                           2661332         1610028     60.50
Blob Component               106136840        39954543     37.64
Blob Bound                   790006766       254708868     32.24
Plane                          2661332          580312     21.81
----------------------------------------------------------------------------
Roots tested:               2644412   eliminated:               964181
Calls to Noise:             1868607   Calls to DNoise:         1868617
----------------------------------------------------------------------------
Shadow Ray Tests:           4343884   Succeeded:               1358385
Transmitted Rays:           1663699
----------------------------------------------------------------------------
Smallest Alloc:                  20 bytes
Largest  Alloc:              600496 bytes
Peak memory used:           7904254 bytes
Total Scene Processing Times
   Parse Time:    0 hours  0 minutes  0 seconds (0 seconds)
   Photon Time:   0 hours  0 minutes  0 seconds (0 seconds)
   Cloth Time:    0 hours  0 minutes  0 seconds (0 seconds)
   Mechsim Time:  0 hours  0 minutes  0 seconds (0 seconds)
   Render Time:   0 hours  1 minutes 15 seconds (75 seconds)
   Postpr. Time:  0 hours  0 minutes  0 seconds (0 seconds)
   Total Time:    0 hours  1 minutes 15 seconds (75 seconds)

3.7.0.beta.35

----------------------------------------------------------------------------
Parser Statistics
----------------------------------------------------------------------------
Finite Objects:            1
Infinite Objects:          1
Light Sources:             3
Total:                     5
-----------------------------------------------------------------------------------------------------------------------------
Render Options
   Quality:  9
   Bounding boxes.......On   Bounding threshold: 10
   Antialiasing.........On  (Method 2, Threshold 0.300, Depth 3, Jitter 
1.00)
----------
Render Statistics
Image Resolution 10 x 10
----------------------------------------------------------------------------
Pixels:              121   Samples:             757   Smpls/Pxl: 6.26
Rays:           51319216   Saved:           3833664   Max Level: 1/5
----------------------------------------------------------------------------
Ray->Shape Intersection          Tests       Succeeded  Percentage
----------------------------------------------------------------------------
Blob                         116511167        61770583     53.02
Blob Component              5529425260      1394028228     25.21
Blob Bound                 41648703980     13122426436     31.51
Plane                        190663483        48890011     25.64
----------------------------------------------------------------------------
Roots tested:             124197493   eliminated:             53757710
Shadow Ray Tests:         143177931   Succeeded:              52063455
Shadow Cache Hits:          1403792
Transmitted Rays:          51318338
----------------------------------------------------------------------------
----------------------------------------------------------------------------
Render Time:
   Photon Time:      No photons
   Radiosity Time:   No radiosity
   Trace Time:       0 hours 54 minutes 40 seconds (3280.049 seconds)
               using 2 thread(s) with 0.-02 CPU-seconds total


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From: Tim Attwood
Subject: Re: transparent blob bug
Date: 16 Jan 2010 22:31:51
Message: <4b5284a7$1@news.povray.org>
> David Burnett wrote:
>> I appear to have hit a transparent blob bug.

This is more of a performance issue...
it's unrelated to ticket #53.

It renders in a reasonable time with 3.6,
so there definitely is something else wrong somewhere
in the 3.7 blob code.


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From: Le Forgeron
Subject: Re: transparent blob bug
Date: 18 Jan 2010 03:10:11
Message: <4b541763@news.povray.org>
Tim Attwood a écrit :
>> David Burnett wrote:
>>> I appear to have hit a transparent blob bug.
> 
> This is more of a performance issue...
> it's unrelated to ticket #53.
> 
> It renders in a reasonable time with 3.6,
> so there definitely is something else wrong somewhere
> in the 3.7 blob code.

Having looked deeply at the 3.7 blob code, during #53, and compared it
to 3.6... the code are nearly identical, IIRC.

But it might be related to the calling code, which was/still doing a
fancy (IMHO) tweaking when counting the depth of a ray.
(see trace.cpp, circa line 192)


-- 
Real software engineers work from 9 to 5, because that is<br/>
the way the job is described in the formal spec.  Working<br/>
late would feel like using an undocumented external procedure.


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