Difference between revisions of "HowTo:Fix artifacts"

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m (HowTo:Fix Artifacts moved to HowTo:Fix artifacts: Capitalisation standard: Initial capital and proper nouns.)
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Wierd speckles on a surface may be caused by:
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On occasion, some objects in your scene may have speckles or what looks like random noise on the surface.  Below are a few possible causes:
  
*Two or more surfaces occupy the same plane. The choice of which surface gets rendered varies from pixel to pixel according to the whim of POV-Ray. Shifting one surface by 0.0001 or some such miniscule but significant amount will usually fix this.
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==Coincident Surfaces==
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*Two or more surfaces occupy the same plane. The choice of which surface gets rendered varies from pixel to pixel according to the whim of POV-Ray. Translating one surface by 0.0001 out of the plane will usually fix this.  This is probably the most common cause of 1px speckles on specific objects in a scene.
  
*You've rendered the scene with certain textures and at low quality and with no anti-aliasing.
 
  
*You've rendered a texture which is supposed to have wierd speckles! ;-)
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==Radiosity==
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*In scenes using radiosity, if the artifacts show up only when radiosity is turned on, then they are caused by radiosity sampling errors.  If you haven't already done so, check the [[Documentation:Tutorial_Section_3.7#Radiosity|Official Documentation on Radiosity]] or the [[HowTo:Use_radiosity|HowTo: tutorial on radiosity]].
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==Transparent and Reflective Surfaces==
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*Scenes that many reflective/transparent surfaces may run afoul of the default [[Documentation:Reference_Section_3.1#Max_Trace_Level|max_trace_level]] setting.  Check the messages from the render, as POV-ray will tell you if the max_trace_level was reached during a render.  If it was reached, raise the max_trace_level to a higher value.
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==Other Causes==
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*You've rendered a scene using certain textures with [[Documentation:Reference_Section_1.3#Anti-Aliasing_Options|anti-aliasing]] turned off.  The difference caused by the use of anti-aliasing can be startling, especially with a texture which is supposed to have weird speckles! ;-) Note that the appearance of speckles on a surface is not only controlled by the pigment statement, but can be the result of a small, bumpy normal, or the use of [[Documentation:Reference_Section_5.1#Crand_Graininess|crand]] in the finish statement.

Revision as of 06:02, 16 August 2009

On occasion, some objects in your scene may have speckles or what looks like random noise on the surface. Below are a few possible causes:

Coincident Surfaces

  • Two or more surfaces occupy the same plane. The choice of which surface gets rendered varies from pixel to pixel according to the whim of POV-Ray. Translating one surface by 0.0001 out of the plane will usually fix this. This is probably the most common cause of 1px speckles on specific objects in a scene.


Radiosity


Transparent and Reflective Surfaces

  • Scenes that many reflective/transparent surfaces may run afoul of the default max_trace_level setting. Check the messages from the render, as POV-ray will tell you if the max_trace_level was reached during a render. If it was reached, raise the max_trace_level to a higher value.


Other Causes

  • You've rendered a scene using certain textures with anti-aliasing turned off. The difference caused by the use of anti-aliasing can be startling, especially with a texture which is supposed to have weird speckles! ;-) Note that the appearance of speckles on a surface is not only controlled by the pigment statement, but can be the result of a small, bumpy normal, or the use of crand in the finish statement.