Hi, I'm new to POV-Ray, and I'm having trouble with rendering. I'm working on a
project to form cross-sections of an object (it's not quite done yet), and I'm
experiencing odd rendering artifacts coming from my bounding box. I'm rendering
the intersection between the box and the object. Making the box invisible
prevents the artifacts but it produces other undesirable effects. I've tried
making all the lights shadowless, but nothing changed.

Does anyone know why these artifacts are caused, and what I can do to get rid of
them?

My files, including a script to render the code, and a set of pre-rendered
images, are located here:

http://www.mediafire.com/file/3jm3i8j2iepepac/sphere-slice-artifact.zip

Thanks for any help.

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Am 15.06.2011 18:35, schrieb Hendricks266:
> Hi, I'm new to POV-Ray, and I'm having trouble with rendering. I'm working on a
> project to form cross-sections of an object (it's not quite done yet), and I'm
> experiencing odd rendering artifacts coming from my bounding box. I'm rendering
> the intersection between the box and the object. Making the box invisible
> prevents the artifacts but it produces other undesirable effects. I've tried
> making all the lights shadowless, but nothing changed.
>
> Does anyone know why these artifacts are caused, and what I can do to get rid of
> them?

Your m_Sphere mesh is not properly closed; while POV-Ray will still 
/try/ to treat such meshes as solids if you use the "inside_vector" 
keyword, this actually only works in very few cases, and you will 
usually get artifacts when using such a mesh in CSG.

In an intersection with a single other object, for instance, the effect 
is that any gaps in the mesh will be projected along the inside_vector, 
causing the surface of the other intersected object to be visible within 
the region of this projection.

The only reliable way to avoid such artifacts is to properly close all 
meshes you use in CSG.

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clipka <ano### [at] anonymousorg> wrote:
>
> Your m_Sphere mesh is not properly closed; while POV-Ray will still
> /try/ to treat such meshes as solids if you use the "inside_vector"
> keyword, this actually only works in very few cases, and you will
> usually get artifacts when using such a mesh in CSG.
>
> In an intersection with a single other object, for instance, the effect
> is that any gaps in the mesh will be projected along the inside_vector,
> causing the surface of the other intersected object to be visible within
> the region of this projection.
>
> The only reliable way to avoid such artifacts is to properly close all
> meshes you use in CSG.

Thanks for the explanation. Is there any simple or automated way to fix the
mesh, or to make sure that it is correct at the beginning of the process? The
POV-Ray files in my pipeline are converted from another format (with a program
of which I can edit its source), so any manual editing methods in the middle
will make the process almost useless.

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Am 16.06.2011 18:01, schrieb Hendricks266:
> clipka<ano### [at] anonymousorg>  wrote:

>> The only reliable way to avoid such artifacts is to properly close all
>> meshes you use in CSG.
>
> Thanks for the explanation. Is there any simple or automated way to fix the
> mesh, or to make sure that it is correct at the beginning of the process? The
> POV-Ray files in my pipeline are converted from another format (with a program
> of which I can edit its source), so any manual editing methods in the middle
> will make the process almost useless.

Unfortunately POV-Ray doesn't provide any way to automatically close 
meshes. (After all, how exactly should POV-Ray know where the missing 
surfaces should be - unless the hole's vertices all happen to lie in a 
single plane.)

Maybe it will actually be easiest to solve this problem at its root, 
i.e. make sure that whatever source data you use doesn't have holes in 
the first place. (Depends of course where you get the data from.)

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