[Bf-docboard] Bf-docboard Digest, Vol 124, Issue 11
Ivan Paulos Tomé
greylica at gmail.com
Mon Jun 22 01:02:57 CEST 2015
A small fix:
*A manifold mesh will always define an even number of non-overlapped surfaces.
2015-06-21 19:50 GMT-03:00, Ivan Paulos Tomé <greylica at gmail.com>:
> OK, agree, so let's reformulate and try to improve the answer.
> (Thank you for the opportunity !)
>
> A manifold mesh is a mesh in which the structure of the connected
> faces in a closed volume will always point the normals (and their
> surfaces) to the outside or to the inside of the mesh without any
> overlaps. If you recalculate those normals, they will always point at
> a predictable direction (To the outside or to the inside of the
> volume). When working with non-closed volumes, a manifold mesh is a
> mesh in which the normals will always define two different and
> non-consecutive surfaces.
>
> A manifold mesh will always define an even number of surfaces.
> -----------------
>
> A non-manifold mesh is a mesh in which the structure of a
> non-overlapped surface (based on it's connected faces) won't determine
> the inside or the outside of a volume based on it's normals, defining
> a single surface for both sides, but ended with flipped normals.
> When working with non-closed volumes, a non-manifold mesh will always
> determine at least one discontinuity at the normal directions, either
> by an inversion of a connected loop, or by an odd number of surfaces.
>
> A non manifold mesh will always define an odd number of surfaces.
>
> 2015-06-21 7:00 GMT-03:00, bf-docboard-request at blender.org
> <bf-docboard-request at blender.org>:
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>> 1. Re: Bf-docboard Digest, Vol 124, Issue 10 (Ivan Paulos Tom?)
>> 2. Re: Bf-docboard Digest, Vol 124, Issue 10 (gandalf3)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Sat, 20 Jun 2015 11:12:32 -0300
>> From: Ivan Paulos Tom? <greylica at gmail.com>
>> Subject: Re: [Bf-docboard] Bf-docboard Digest, Vol 124, Issue 10
>> To: bf-docboard at blender.org
>> Message-ID:
>> <CA+Zt8s5uuhroeDWpc65pzJyeFivq6dL7E8d2jP8G7fQS-8EMUg at mail.gmail.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> Hi friends !
>>
>> The question about double sided and single sided faces, and manifold
>> or non-manifold meshes is related to it's normals.
>>
>> The normal of the face is the face that is shaded.
>>
>> Normals, are generally pointed to a single side of the objects. And
>> normally, because of the shading, normals are pointed (when we have
>> closed meshes) externally to the world.
>>
>> The standard in the majority of the softwares, is to have a single
>> sided face (only one normal per face, which means that the materials
>> assigned will only be detected and rendered at the normal direction),
>> but for compatibility with game engines, we can make Blender have
>> double sided faces too.
>>
>> A manifold mesh is a mesh which faces are completely pointing to the
>> outside or to the inside of the mesh, if you recalculate those
>> normals, they will always point at a single direction (outside or
>> inside).
>>
>> A non-manifold mesh is a mesh in which we can't determine the outside
>> and the inside of the mesh, because the normals will *always" point at
>> diferent directions, and it doesn't matter if we recalculate them
>> using a tool or flip them manually, due to the way that the structure
>> of the mesh is conected.
>>
>> Cheers !
>>
>> 2015-06-20 7:00 GMT-03:00, bf-docboard-request at blender.org
>> <bf-docboard-request at blender.org>:
>>> Send Bf-docboard mailing list submissions to
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>>>
>>>
>>> Today's Topics:
>>>
>>> 1. Some weak points in the documentation. (brasshat at core.com)
>>> 2. Re: Some weak points in the documentation. (gandalf3)
>>> 3. Re: Some weak points in the documentation. (brasshat at core.com)
>>> 4. Re: Some weak points in the documentation. (brasshat at core.com)
>>>
>>>
>>> ----------------------------------------------------------------------
>>>
>>> Message: 1
>>> Date: Sat, 20 Jun 2015 00:21:12 -0400 (EDT)
>>> From: brasshat at core.com
>>> Subject: [Bf-docboard] Some weak points in the documentation.
>>> To: "Blender Documentation Project" <bf-docboard at blender.org>
>>> Message-ID: <65486.99.58.2.94.1434774072.squirrel at webmail.core.com>
>>> Content-Type: text/plain; charset="iso-8859-1"
>>>
>>>
>>>
>>> Friends,
>>>
>>> While answering a question on Blender Stack Exchange,
>>> I went looking for some things in the manual that I thought should be
>>> there, but were not.
>>>
>>> 1) Any information on what Blender
>>> considers to be an interior face. There was no entry in the glossary,
>>> and
>>> doing a search using the parameter "interior faces" did not
>>> provide any hits. The only explanation I located was in the tool tip,
>>> where a hidden face is defines as a face where all of the edges of the
>>> face have more than 2 face users.
>>>
>>> 2) I could also not find any
>>> information on removing non-manifold bits of a mesh when I attempted to
>>> search on "non manifold".
>>>
>>> Both interior faces
>>> and? non-manifold are items in the select menu of the 3D viewport
>>> header.
>>>
>>> I'd add them myself, but haven't been able to rustle up
>>> enough time to learn to make the edits.
>>>
>>> Noel Stoutenburg
>>> -------------- next part --------------
>>> An HTML attachment was scrubbed...
>>> URL:
>>> http://lists.blender.org/pipermail/bf-docboard/attachments/20150620/74f28fa9/attachment.html
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 2
>>> Date: Fri, 19 Jun 2015 23:44:55 -0700
>>> From: gandalf3 <zzyxpaw at gmail.com>
>>> Subject: Re: [Bf-docboard] Some weak points in the documentation.
>>> To: Blender Documentation Project <bf-docboard at blender.org>
>>> Message-ID: <55850BE7.4040103 at gmail.com>
>>> Content-Type: text/plain; charset="windows-1252"
>>>
>>> On 06/19/15 21:21, brasshat at core.com wrote:
>>>> Friends,
>>>>
>>>> While answering a question on Blender Stack Exchange, I went looking
>>>> for some things in the manual that I thought should be there, but were
>>>> not.
>>>>
>>>> 1) Any information on what Blender considers to be an interior face.
>>>> There was no entry in the glossary, and doing a search using the
>>>> parameter "interior faces" did not provide any hits. The only
>>>> explanation I located was in the tool tip, where a hidden face is
>>>> defines as a face where all of the edges of the face have more than 2
>>>> face users.
>>>>
>>>> 2) I could also not find any information on removing non-manifold bits
>>>> of a mesh when I attempted to search on "non manifold".
>>>>
>>>> Both interior faces and non-manifold are items in the select menu of
>>>> the 3D viewport header.
>>>>
>>>> I'd add them myself, but haven't been able to rustle up enough time to
>>>> learn to make the edits.
>>>>
>>>> Noel Stoutenburg
>>>>
>>>>
>>>> _______________________________________________
>>>> Bf-docboard mailing list
>>>> Bf-docboard at blender.org
>>>> http://lists.blender.org/mailman/listinfo/bf-docboard
>>> They are here:
>>> http://blender.org/manual/modeling/meshes/selecting/advanced.html
>>>
>>> Not sure why 'non manifold' and 'non-manifold' don't turn up any
>>> results, but 'manifold' gives some.
>>>
>>> --
>>> -gandalf3
>>>
>>> -------------- next part --------------
>>> An HTML attachment was scrubbed...
>>> URL:
>>> http://lists.blender.org/pipermail/bf-docboard/attachments/20150619/6c507218/attachment-0001.htm
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 3
>>> Date: Sat, 20 Jun 2015 04:08:51 -0400 (EDT)
>>> From: brasshat at core.com
>>> Subject: Re: [Bf-docboard] Some weak points in the documentation.
>>> To: bf-docboard at blender.org
>>> Message-ID: <51458.99.58.2.94.1434787731.squirrel at webmail.core.com>
>>> Content-Type: text/plain; charset="iso-8859-1"
>>>
>>>
>>>
>>> Gandalf3,
>>>
>>> Regarding your question:
>>>
>>>>? Not
>>> sure why 'non manifold' and 'non-manifold' don't turn up any
>>> results,
>>> but 'manifold' gives some.
>>>
>>> I can't explain "non
>>> manifold", but "non-manifold" does not appear, because in
>>> every instance there is a space between the hyphen and the word
>>> "manifold", , and if the search facilities are case sensitive,
>>> both the initial letters N and M are capitalized, so "Non-
>>> Manifold.
>>>
>>> Noel Stoutenburg
>>> -------------- next part --------------
>>> An HTML attachment was scrubbed...
>>> URL:
>>> http://lists.blender.org/pipermail/bf-docboard/attachments/20150620/80918aff/attachment-0001.htm
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 4
>>> Date: Sat, 20 Jun 2015 04:27:38 -0400 (EDT)
>>> From: brasshat at core.com
>>> Subject: Re: [Bf-docboard] Some weak points in the documentation.
>>> To: "Blender Documentation Project" <bf-docboard at blender.org>
>>> Message-ID: <51715.99.58.2.94.1434788858.squirrel at webmail.core.com>
>>> Content-Type: text/plain; charset="iso-8859-1"
>>>
>>>
>>>
>>> Ooops.?
>>>
>>> I didn't look closely enough. and found after
>>> hitting the "send" button that this statement,
>>>
>>>>
>>> both the initial letters N and M are capitalized, so "Non-
>>>>
>>> Manifold.
>>>
>>> is not accurate.
>>>
>>> Noel Stoutenburg
>>> -------------- next part --------------
>>> An HTML attachment was scrubbed...
>>> URL:
>>> http://lists.blender.org/pipermail/bf-docboard/attachments/20150620/19b23ce3/attachment-0001.htm
>>>
>>>
>>> ------------------------------
>>>
>>> _______________________________________________
>>> Bf-docboard mailing list
>>> Bf-docboard at blender.org
>>> http://lists.blender.org/mailman/listinfo/bf-docboard
>>>
>>>
>>> End of Bf-docboard Digest, Vol 124, Issue 10
>>> ********************************************
>>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Sat, 20 Jun 2015 11:33:29 -0700
>> From: gandalf3 <zzyxpaw at gmail.com>
>> Subject: Re: [Bf-docboard] Bf-docboard Digest, Vol 124, Issue 10
>> To: Blender Documentation Project <bf-docboard at blender.org>
>> Message-ID: <5585B1F9.9070102 at gmail.com>
>> Content-Type: text/plain; charset="windows-1252"
>>
>> On 06/20/15 07:12, Ivan Paulos Tom? wrote:
>>> Hi friends !
>>>
>>> The question about double sided and single sided faces, and manifold
>>> or non-manifold meshes is related to it's normals.
>>>
>>> The normal of the face is the face that is shaded.
>>>
>>> Normals, are generally pointed to a single side of the objects. And
>>> normally, because of the shading, normals are pointed (when we have
>>> closed meshes) externally to the world.
>>>
>>> The standard in the majority of the softwares, is to have a single
>>> sided face (only one normal per face, which means that the materials
>>> assigned will only be detected and rendered at the normal direction),
>>> but for compatibility with game engines, we can make Blender have
>>> double sided faces too.
>>>
>>> A manifold mesh is a mesh which faces are completely pointing to the
>>> outside or to the inside of the mesh, if you recalculate those
>>> normals, they will always point at a single direction (outside or
>>> inside).
>>>
>>> A non-manifold mesh is a mesh in which we can't determine the outside
>>> and the inside of the mesh, because the normals will *always" point at
>>> diferent directions, and it doesn't matter if we recalculate them
>>> using a tool or flip them manually, due to the way that the structure
>>> of the mesh is conected.
>> Well, it is possible to have non-manifold meshes with consistent normals
>> (e.g. a 2D plane)
>> And it's possible to have manifold geometry which cannot have consistent
>> normals (e.g. a klien bottle
>> <https://en.wikipedia.org/wiki/Klein_bottle>)
>>
>> So this definition doesn't hold up under all circumstances.
>>
>> The manual doesn't really attempt to define it beyond saying
>> "non-manifold geometry cannot exist in the real world", but this too is
>> slightly misleading (klien bottles are manifold, but they cannot exist
>> in the real world because they intersect themselves).
>> Perhaps it would be nice to write up a detailed explanation of all this
>> on the manual somewhere (like this
>> <http://blender.stackexchange.com/q/7910/599>, but better).
>>
>>>
>>> Cheers !
>>>
>>> 2015-06-20 7:00 GMT-03:00, bf-docboard-request at blender.org
>>> <bf-docboard-request at blender.org>:
>>>> Send Bf-docboard mailing list submissions to
>>>> bf-docboard at blender.org
>>>>
>>>> To subscribe or unsubscribe via the World Wide Web, visit
>>>> http://lists.blender.org/mailman/listinfo/bf-docboard
>>>> or, via email, send a message with subject or body 'help' to
>>>> bf-docboard-request at blender.org
>>>>
>>>> You can reach the person managing the list at
>>>> bf-docboard-owner at blender.org
>>>>
>>>> When replying, please edit your Subject line so it is more specific
>>>> than "Re: Contents of Bf-docboard digest..."
>>>>
>>>>
>>>> Today's Topics:
>>>>
>>>> 1. Some weak points in the documentation. (brasshat at core.com)
>>>> 2. Re: Some weak points in the documentation. (gandalf3)
>>>> 3. Re: Some weak points in the documentation. (brasshat at core.com)
>>>> 4. Re: Some weak points in the documentation. (brasshat at core.com)
>>>>
>>>>
>>>> ----------------------------------------------------------------------
>>>>
>>>> Message: 1
>>>> Date: Sat, 20 Jun 2015 00:21:12 -0400 (EDT)
>>>> From: brasshat at core.com
>>>> Subject: [Bf-docboard] Some weak points in the documentation.
>>>> To: "Blender Documentation Project" <bf-docboard at blender.org>
>>>> Message-ID: <65486.99.58.2.94.1434774072.squirrel at webmail.core.com>
>>>> Content-Type: text/plain; charset="iso-8859-1"
>>>>
>>>>
>>>>
>>>> Friends,
>>>>
>>>> While answering a question on Blender Stack Exchange,
>>>> I went looking for some things in the manual that I thought should be
>>>> there, but were not.
>>>>
>>>> 1) Any information on what Blender
>>>> considers to be an interior face. There was no entry in the glossary,
>>>> and
>>>> doing a search using the parameter "interior faces" did not
>>>> provide any hits. The only explanation I located was in the tool tip,
>>>> where a hidden face is defines as a face where all of the edges of the
>>>> face have more than 2 face users.
>>>>
>>>> 2) I could also not find any
>>>> information on removing non-manifold bits of a mesh when I attempted to
>>>> search on "non manifold".
>>>>
>>>> Both interior faces
>>>> and? non-manifold are items in the select menu of the 3D viewport
>>>> header.
>>>>
>>>> I'd add them myself, but haven't been able to rustle up
>>>> enough time to learn to make the edits.
>>>>
>>>> Noel Stoutenburg
>>>> -------------- next part --------------
>>>> An HTML attachment was scrubbed...
>>>> URL:
>>>> http://lists.blender.org/pipermail/bf-docboard/attachments/20150620/74f28fa9/attachment.html
>>>>
>>>>
>>>> ------------------------------
>>>>
>>>> Message: 2
>>>> Date: Fri, 19 Jun 2015 23:44:55 -0700
>>>> From: gandalf3 <zzyxpaw at gmail.com>
>>>> Subject: Re: [Bf-docboard] Some weak points in the documentation.
>>>> To: Blender Documentation Project <bf-docboard at blender.org>
>>>> Message-ID: <55850BE7.4040103 at gmail.com>
>>>> Content-Type: text/plain; charset="windows-1252"
>>>>
>>>> On 06/19/15 21:21, brasshat at core.com wrote:
>>>>> Friends,
>>>>>
>>>>> While answering a question on Blender Stack Exchange, I went looking
>>>>> for some things in the manual that I thought should be there, but were
>>>>> not.
>>>>>
>>>>> 1) Any information on what Blender considers to be an interior face.
>>>>> There was no entry in the glossary, and doing a search using the
>>>>> parameter "interior faces" did not provide any hits. The only
>>>>> explanation I located was in the tool tip, where a hidden face is
>>>>> defines as a face where all of the edges of the face have more than 2
>>>>> face users.
>>>>>
>>>>> 2) I could also not find any information on removing non-manifold bits
>>>>> of a mesh when I attempted to search on "non manifold".
>>>>>
>>>>> Both interior faces and non-manifold are items in the select menu of
>>>>> the 3D viewport header.
>>>>>
>>>>> I'd add them myself, but haven't been able to rustle up enough time to
>>>>> learn to make the edits.
>>>>>
>>>>> Noel Stoutenburg
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Bf-docboard mailing list
>>>>> Bf-docboard at blender.org
>>>>> http://lists.blender.org/mailman/listinfo/bf-docboard
>>>> They are here:
>>>> http://blender.org/manual/modeling/meshes/selecting/advanced.html
>>>>
>>>> Not sure why 'non manifold' and 'non-manifold' don't turn up any
>>>> results, but 'manifold' gives some.
>>>>
>>>> --
>>>> -gandalf3
>>>>
>>>> -------------- next part --------------
>>>> An HTML attachment was scrubbed...
>>>> URL:
>>>> http://lists.blender.org/pipermail/bf-docboard/attachments/20150619/6c507218/attachment-0001.htm
>>>>
>>>>
>>>> ------------------------------
>>>>
>>>> Message: 3
>>>> Date: Sat, 20 Jun 2015 04:08:51 -0400 (EDT)
>>>> From: brasshat at core.com
>>>> Subject: Re: [Bf-docboard] Some weak points in the documentation.
>>>> To: bf-docboard at blender.org
>>>> Message-ID: <51458.99.58.2.94.1434787731.squirrel at webmail.core.com>
>>>> Content-Type: text/plain; charset="iso-8859-1"
>>>>
>>>>
>>>>
>>>> Gandalf3,
>>>>
>>>> Regarding your question:
>>>>
>>>>> ? Not
>>>> sure why 'non manifold' and 'non-manifold' don't turn up any
>>>> results,
>>>> but 'manifold' gives some.
>>>>
>>>> I can't explain "non
>>>> manifold", but "non-manifold" does not appear, because in
>>>> every instance there is a space between the hyphen and the word
>>>> "manifold", , and if the search facilities are case sensitive,
>>>> both the initial letters N and M are capitalized, so "Non-
>>>> Manifold.
>>>>
>>>> Noel Stoutenburg
>>>> -------------- next part --------------
>>>> An HTML attachment was scrubbed...
>>>> URL:
>>>> http://lists.blender.org/pipermail/bf-docboard/attachments/20150620/80918aff/attachment-0001.htm
>>>>
>>>>
>>>> ------------------------------
>>>>
>>>> Message: 4
>>>> Date: Sat, 20 Jun 2015 04:27:38 -0400 (EDT)
>>>> From: brasshat at core.com
>>>> Subject: Re: [Bf-docboard] Some weak points in the documentation.
>>>> To: "Blender Documentation Project" <bf-docboard at blender.org>
>>>> Message-ID: <51715.99.58.2.94.1434788858.squirrel at webmail.core.com>
>>>> Content-Type: text/plain; charset="iso-8859-1"
>>>>
>>>>
>>>>
>>>> Ooops.?
>>>>
>>>> I didn't look closely enough. and found after
>>>> hitting the "send" button that this statement,
>>>>
>>>> both the initial letters N and M are capitalized, so "Non-
>>>> Manifold.
>>>>
>>>> is not accurate.
>>>>
>>>> Noel Stoutenburg
>>>> -------------- next part --------------
>>>> An HTML attachment was scrubbed...
>>>> URL:
>>>> http://lists.blender.org/pipermail/bf-docboard/attachments/20150620/19b23ce3/attachment-0001.htm
>>>>
>>>>
>>>> ------------------------------
>>>>
>>>> _______________________________________________
>>>> Bf-docboard mailing list
>>>> Bf-docboard at blender.org
>>>> http://lists.blender.org/mailman/listinfo/bf-docboard
>>>>
>>>>
>>>> End of Bf-docboard Digest, Vol 124, Issue 10
>>>> ********************************************
>>>>
>>> _______________________________________________
>>> Bf-docboard mailing list
>>> Bf-docboard at blender.org
>>> http://lists.blender.org/mailman/listinfo/bf-docboard
>>
>>
>> --
>> -gandalf3
>>
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>> ------------------------------
>>
>> _______________________________________________
>> Bf-docboard mailing list
>> Bf-docboard at blender.org
>> http://lists.blender.org/mailman/listinfo/bf-docboard
>>
>>
>> End of Bf-docboard Digest, Vol 124, Issue 11
>> ********************************************
>>
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