Re: equirectangular uv

[pedro santos]

Hi Pierre
I didn't make the UV to grid part of it available yet. But the Polygon to
UV was made in response to another topic here in the mailing list.You can
also check it out on rray: "Unit UV"

Cheers

On Tue, May 24, 2016 at 4:02 PM, Pierre Schiller <
activemotionpictu...@gmail.com> wrote:

> @Pedro Santos, is this an in-house solution? looks pretty solid!
> https://gfycat.com/ShabbySeriousDrafthorse
> Or is it available somewhere?
> Thanks! :D
>
> On Tue, May 17, 2016 at 8:51 PM, Matt Lind  wrote:
>
>> I should also add:
>>
>> If you apply a spherical projection onto a cube which has Catmull-Clark
>> subdivision smoothing applied to it to become a sphere, the edge flow of
>> the
>> polygons as seen in the texture editor will almost exactly match the flow
>> as
>> seen in equirectangular projections floating around on the internet when
>> doing a Google search for examples.  That is a marked improvement over
>> applying a spherical projection onto a primitive sphere which shows up as
>> a
>> grid with pinched poles at the top and bottom of the editor.
>>
>> If you place your unfold cut lines along the center of the face(s) of the
>> subdivided cube, the resulting unfold will resemble a Mercator projection,
>> but with skewing as unfold has flaws as detailed in an earlier post.
>>
>> Matt
>>
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>> Softimage Mailing List.
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>> with "unsubscribe" in the subject, and reply to confirm.
>>
>
>
>
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> Cinema & TV production
> Video Reel 
>
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Re: equirectangular uv

[Pierre Schiller]

@Pedro Santos, is this an in-house solution? looks pretty solid!
https://gfycat.com/ShabbySeriousDrafthorse
Or is it available somewhere?
Thanks! :D

On Tue, May 17, 2016 at 8:51 PM, Matt Lind  wrote:

> I should also add:
>
> If you apply a spherical projection onto a cube which has Catmull-Clark
> subdivision smoothing applied to it to become a sphere, the edge flow of
> the
> polygons as seen in the texture editor will almost exactly match the flow
> as
> seen in equirectangular projections floating around on the internet when
> doing a Google search for examples.  That is a marked improvement over
> applying a spherical projection onto a primitive sphere which shows up as a
> grid with pinched poles at the top and bottom of the editor.
>
> If you place your unfold cut lines along the center of the face(s) of the
> subdivided cube, the resulting unfold will resemble a Mercator projection,
> but with skewing as unfold has flaws as detailed in an earlier post.
>
> Matt
>
> --
> Softimage Mailing List.
> To unsubscribe, send a mail to softimage-requ...@listproc.autodesk.com
> with "unsubscribe" in the subject, and reply to confirm.
>



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Re: equirectangular uv

[Matt Lind]

I should also add:

If you apply a spherical projection onto a cube which has Catmull-Clark 
subdivision smoothing applied to it to become a sphere, the edge flow of the 
polygons as seen in the texture editor will almost exactly match the flow as 
seen in equirectangular projections floating around on the internet when 
doing a Google search for examples.  That is a marked improvement over 
applying a spherical projection onto a primitive sphere which shows up as a 
grid with pinched poles at the top and bottom of the editor.

If you place your unfold cut lines along the center of the face(s) of the 
subdivided cube, the resulting unfold will resemble a Mercator projection, 
but with skewing as unfold has flaws as detailed in an earlier post.

Matt

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Re: equirectangular uv

[Matt Lind]

No.  You're mixing two separate thoughts together.

The first few messages which started this thread mentioned a spherical 
projection doesn't work at the poles because of the usual distortion, and 
the sphere was modified.

My comment of the viewport issue was targeting the spherical projection at 
the poles being distorted.  I ran some experiments using spherical 
projection on various meshes and discovered that while the projection looks 
messed up in the viewports, it will render cleanly (without distortion) if 
you capture it using rendermap.  If you export that captured image to Unity, 
there shouldn't be any issue.  Therefore don't worry about spherical mapping 
distortion visible in the viewports because the issue is confined to 
Softimage.

Your plugin is a different issue.  As polygons are added/removed, as shown 
in your video, random parts of the texture space are assigned to the new 
polygons.  You answered the question by stating you're using a random seed, 
and therefore not attempting to put the correct UVs into that new polygon.

Matt





Date: Tue, 17 May 2016 15:36:21 +0100
From: pedro santos 
Subject: Re: equirectangular uv
To: Softimage Mailing List 

Matt at that particular point I'm using "Random Seed" input to randomize
the UV location, hence that happening. So what you're saying it's not
something that is wrongly set and what I show in there wouldn't help, since
it's a viewport problem?

Cheers

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Re: equirectangular uv

[Francisco Criado]

Pedro,
Any chance to trying this? Already have my sphere with correct uvs but
yours looks nicer ;)

F.


2016-05-17 11:36 GMT-03:00 pedro santos :

> Matt at that particular point I'm using "Random Seed" input to randomize
> the UV location, hence that happening. So what you're saying it's not
> something that is wrongly set and what I show in there wouldn't help, since
> it's a viewport problem?
>
> Cheers
>
> On Tue, May 17, 2016 at 2:38 AM, Matt Lind  wrote:
>
>> Implicit simply means the texture is projected without explicitly defined
>> UV
>> coordinates per polygon.  Like using a slide projector to project the
>> image
>> onto a surface.  That's why it's confined to the basic texture projection
>> types as the method to project the image onto the surface needs to be
>> defined as an algorithm.  The advantage is polygon surfaces can get more
>> granular/precise placement of texels because normally they rely on normals
>> and UVs defined at the vertices and interpolated across the polygon for
>> placement which gets less accurate the larger the polygon is relative to
>> the
>> texture space coverage.  That is independent of an equirectangular
>> projection mapping method which Softimage does not have by default (other
>> than spherical mapping).
>>
>> I don't think it's strictly a mental ray feature, but even if it were, any
>> surface attribute produced by mental ray can be captured using
>> rendermap/ultimapper/lightmapper and exported where needed.  You may be
>> able
>> to build your own projection using ICE, but a mental ray shader would
>> produce better results as it has the advantage of the subsampling and
>> interpolation methods available in the renderer which are significantly
>> higher quality and more granular than anything ICE has access to.
>> Developing a shader would also be easier.
>>
>> I conducted an experiment by applying Catmull-Clark subdivision smoothing
>> to
>> a cube, applying a spherical texture projection, then rendermapping the
>> result.  After that, I created my own spherical mapping shader in the
>> rendertree using the available nodes, applied it to the cube, then
>> rendermapped that too.  Comparing the results side by side revealed some
>> broken internals of Softimage.
>>
>> As it turns out, the default spherical mapping as seen in the viewports is
>> all Fd up, but if you rendermap that projection, the resulting image
>> will be perfectly clean without distortion at the poles.  Conversely, my
>> self-devised spherical shader built in the rendertree looked perfect in
>> the
>> viewports/render region, but rendermap captured distortion at the poles
>> equivalent to what you see in the viewports with the default spherical
>> projection.  Apparently the viewports and rendermap use different
>> algorithms
>> for the same work.
>>
>> Getting back to the original question - the fact you see garbage at the
>> poles of the sphere in the Softimage viewports should be of no concern
>> because it's isolated to the viewports and should not transfer to Unity or
>> whatever engine you're exporting your stuff.  Equirectangular projections
>> created with Rendermap will come out clean.
>>
>> Matt
>>
>>
>>
>> Date: Sat, 14 May 2016 17:33:32 +0200
>> From: "Sven Constable" 
>> Subject: RE: equirectangular uv
>> To: 
>>
>> To fix distortion on the poles, XSI has a special mapping feature called
>> 'implicit' (Clusters/?Texture Projection Def), but this is actually a
>> mental
>> ray feature and doesn't deal with UVs at all. So when exporting meshes you
>> cannot use it, I think. I'm not familiar with Unity unfortunatly, maybe
>> there is a similar feature for spherical projections not using UVs but
>> instead a special projection method (perfect spherical) ?
>>
>> Otherwise, since a sphere always has poles/singularities you will get
>> distortions on them. Workaround could get rid of the poles by deleting the
>> inmost polygons on each pole, duplicating the resulting (open) edge loop,
>> and scale it to zero. Resulting in many point on the same spot. Then
>> relaxing them in the texture editor. Results could be ok, not sure. Maybe
>> I'm  overcomplicating it.  Matt Lind needs to chime in :)
>>
>> Can't you use cubic mapping? That should avoid the problem in the first
>> place.
>>
>> sven
>>
>> --
>> Softimage Mailing List.
>> To unsubscribe, send a ma

Re: equirectangular uv

[pedro santos]

Matt at that particular point I'm using "Random Seed" input to randomize
the UV location, hence that happening. So what you're saying it's not
something that is wrongly set and what I show in there wouldn't help, since
it's a viewport problem?

Cheers

On Tue, May 17, 2016 at 2:38 AM, Matt Lind  wrote:

> Implicit simply means the texture is projected without explicitly defined
> UV
> coordinates per polygon.  Like using a slide projector to project the image
> onto a surface.  That's why it's confined to the basic texture projection
> types as the method to project the image onto the surface needs to be
> defined as an algorithm.  The advantage is polygon surfaces can get more
> granular/precise placement of texels because normally they rely on normals
> and UVs defined at the vertices and interpolated across the polygon for
> placement which gets less accurate the larger the polygon is relative to
> the
> texture space coverage.  That is independent of an equirectangular
> projection mapping method which Softimage does not have by default (other
> than spherical mapping).
>
> I don't think it's strictly a mental ray feature, but even if it were, any
> surface attribute produced by mental ray can be captured using
> rendermap/ultimapper/lightmapper and exported where needed.  You may be
> able
> to build your own projection using ICE, but a mental ray shader would
> produce better results as it has the advantage of the subsampling and
> interpolation methods available in the renderer which are significantly
> higher quality and more granular than anything ICE has access to.
> Developing a shader would also be easier.
>
> I conducted an experiment by applying Catmull-Clark subdivision smoothing
> to
> a cube, applying a spherical texture projection, then rendermapping the
> result.  After that, I created my own spherical mapping shader in the
> rendertree using the available nodes, applied it to the cube, then
> rendermapped that too.  Comparing the results side by side revealed some
> broken internals of Softimage.
>
> As it turns out, the default spherical mapping as seen in the viewports is
> all Fd up, but if you rendermap that projection, the resulting image
> will be perfectly clean without distortion at the poles.  Conversely, my
> self-devised spherical shader built in the rendertree looked perfect in the
> viewports/render region, but rendermap captured distortion at the poles
> equivalent to what you see in the viewports with the default spherical
> projection.  Apparently the viewports and rendermap use different
> algorithms
> for the same work.
>
> Getting back to the original question - the fact you see garbage at the
> poles of the sphere in the Softimage viewports should be of no concern
> because it's isolated to the viewports and should not transfer to Unity or
> whatever engine you're exporting your stuff.  Equirectangular projections
> created with Rendermap will come out clean.
>
> Matt
>
>
>
> Date: Sat, 14 May 2016 17:33:32 +0200
> From: "Sven Constable" 
> Subject: RE: equirectangular uv
> To: 
>
> To fix distortion on the poles, XSI has a special mapping feature called
> 'implicit' (Clusters/?Texture Projection Def), but this is actually a
> mental
> ray feature and doesn't deal with UVs at all. So when exporting meshes you
> cannot use it, I think. I'm not familiar with Unity unfortunatly, maybe
> there is a similar feature for spherical projections not using UVs but
> instead a special projection method (perfect spherical) ?
>
> Otherwise, since a sphere always has poles/singularities you will get
> distortions on them. Workaround could get rid of the poles by deleting the
> inmost polygons on each pole, duplicating the resulting (open) edge loop,
> and scale it to zero. Resulting in many point on the same spot. Then
> relaxing them in the texture editor. Results could be ok, not sure. Maybe
> I'm  overcomplicating it.  Matt Lind needs to chime in :)
>
> Can't you use cubic mapping? That should avoid the problem in the first
> place.
>
> sven
>
> --
> Softimage Mailing List.
> To unsubscribe, send a mail to softimage-requ...@listproc.autodesk.com
> with "unsubscribe" in the subject, and reply to confirm.
>



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RE: equirectangular uv

[Matt Lind]

Implicit simply means the texture is projected without explicitly defined UV
coordinates per polygon.  Like using a slide projector to project the image
onto a surface.  That's why it's confined to the basic texture projection
types as the method to project the image onto the surface needs to be
defined as an algorithm.  The advantage is polygon surfaces can get more
granular/precise placement of texels because normally they rely on normals
and UVs defined at the vertices and interpolated across the polygon for
placement which gets less accurate the larger the polygon is relative to the
texture space coverage.  That is independent of an equirectangular
projection mapping method which Softimage does not have by default (other
than spherical mapping).

I don't think it's strictly a mental ray feature, but even if it were, any
surface attribute produced by mental ray can be captured using
rendermap/ultimapper/lightmapper and exported where needed.  You may be able
to build your own projection using ICE, but a mental ray shader would
produce better results as it has the advantage of the subsampling and
interpolation methods available in the renderer which are significantly
higher quality and more granular than anything ICE has access to.
Developing a shader would also be easier.

I conducted an experiment by applying Catmull-Clark subdivision smoothing to
a cube, applying a spherical texture projection, then rendermapping the
result.  After that, I created my own spherical mapping shader in the
rendertree using the available nodes, applied it to the cube, then
rendermapped that too.  Comparing the results side by side revealed some
broken internals of Softimage.

As it turns out, the default spherical mapping as seen in the viewports is
all Fd up, but if you rendermap that projection, the resulting image
will be perfectly clean without distortion at the poles.  Conversely, my
self-devised spherical shader built in the rendertree looked perfect in the
viewports/render region, but rendermap captured distortion at the poles
equivalent to what you see in the viewports with the default spherical
projection.  Apparently the viewports and rendermap use different algorithms
for the same work.

Getting back to the original question - the fact you see garbage at the 
poles of the sphere in the Softimage viewports should be of no concern 
because it's isolated to the viewports and should not transfer to Unity or 
whatever engine you're exporting your stuff.  Equirectangular projections 
created with Rendermap will come out clean.

Matt



Date: Sat, 14 May 2016 17:33:32 +0200
From: "Sven Constable" 
Subject: RE: equirectangular uv
To: 

To fix distortion on the poles, XSI has a special mapping feature called
'implicit' (Clusters/?Texture Projection Def), but this is actually a mental
ray feature and doesn't deal with UVs at all. So when exporting meshes you
cannot use it, I think. I'm not familiar with Unity unfortunatly, maybe
there is a similar feature for spherical projections not using UVs but
instead a special projection method (perfect spherical) ?

Otherwise, since a sphere always has poles/singularities you will get
distortions on them. Workaround could get rid of the poles by deleting the
inmost polygons on each pole, duplicating the resulting (open) edge loop,
and scale it to zero. Resulting in many point on the same spot. Then
relaxing them in the texture editor. Results could be ok, not sure. Maybe
I'm  overcomplicating it.  Matt Lind needs to chime in :)

Can't you use cubic mapping? That should avoid the problem in the first
place.

sven 

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Re: equirectangular uv

[Matt Lind]

Why does adding/removing a polygon cause the sphere to pick up a texture 
from the wrong part of the projection?

The last few seconds of the video shows a polygon being inserted in the 
front, but is mapped with a "&" symbol which is located at the opposite end 
of the UV texture space from those mapped to the adjacent polygons.

Matt



Date: Mon, 16 May 2016 18:57:43 +0100
From: pedro santos 
Subject: Re: equirectangular uv
To: Softimage Mailing List 

Does this help?
https://gfycat.com/ShabbySeriousDrafthorse

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Re: equirectangular uv

[Francisco Criado]

Nice!
is it available?
F.


2016-05-16 14:57 GMT-03:00 pedro santos :

> Does this help?
> https://gfycat.com/ShabbySeriousDrafthorse
>
> On Sun, May 15, 2016 at 7:02 AM, Matt Lind  wrote:
>
>> I would need to see the problem to give a good answer as I'm not sure what
>> I'm envisioning in my head matches what is being described.
>>
>> Knowing how the sphere is modified is important.  Unfold tries to evenly
>> distribute the texture space of the texture to match the topology while
>> minimizing stretch/compression.   If the poles have elongated triangles,
>> then that will obviously play into the distribution of the unfolded
>> texture
>> (in theory it shouldn't, but in practice it does).  One way to mitigate
>> that
>> issue is to add vertices and perpendicular edges at regular intervals
>> along
>> the elongated edges to closely match the spacing of other edges around the
>> rest of the mesh, but that will have limited influence on the result and
>> is
>> more of a brute force technique.
>>
>> Unfold is also a flawed tool as even simple cases come out distorted.  for
>> example, get a primitive sphere and imagine it's the Earth.  Place a
>> vertical UV seam down one side at the international date line, then two
>> more
>> seams at the arctic/antarctic circles.  Deselect the vertical edges
>> connecting the circles to the poles.  Now unfold the mesh.  Notice the
>> sphere is splayed in butterfly fashion, but one half is larger than the
>> other and slightly off kilter in alignment with the texture editor.  The
>> circle at one pole is often (but not always) larger than the other circle
>> too.  These are the kinds of issues you'll battle, but on more complex
>> cases
>> they'll be too complex to solve without resorting to cleanup via
>> pushing/pulling points to correct the flawed parts of the unfold.
>>
>> However, let's put all that aside and look at the goal from the beginning
>> and not the current situation which has a roadblock.
>>
>> An equirectangular projection comes in a few flavors, but most are similar
>> to a cubic projection.  The main difference is in how the top and bottom
>> sides are projected.  Simple analysis of the problem would suggest one
>> could
>> take a cube and use Catmull-Clark subdivision smoothing to round it into a
>> sphere.  That would accomplish nicer edge placement which closely match
>> the
>> meridians of the projection to handle (or fabricate) the texture space.  A
>> single vertical seam from pole to pole (despite no physical poles) could
>> be
>> used to unfold and splay the sphere to accept/define the projection, but
>> subtle details may need to be tweaked for a perfect match.
>>
>> Alternately, use rendermap applied to a sphere to capture the external
>> world.  The rendermap generated image should mimic an equirectangular
>> projection. You may have to open the poles like the Earth without the
>> arctic/antarctic circles, for example, to adjust the field of view for the
>> rendermap process.  Invert the sphere's normals so rendermap points
>> outwards
>> into the world instead of inwards towards the sphere's surfaceand of
>> course, exclude self or make the material 100% transparent so it doesn't
>> block the rendermap camera from seeing the world.  Since rendermap travels
>> texel-to-texel along the geometry, a high resolution image and smooth
>> surface are really important.  I'd encourage you to use a NURBS sphere
>> with
>> view dependent smoothing for best results.  you set those in the sphere's
>> geometry approximations PPG.  Try setting length/distance/angle values to
>> less than 2 degrees and 0.5 units, activate view dependent subdivision
>> smoothing, and make sure the min/max subdivision limits are increased
>> beyond
>> the default 1,3 (well, just the max.  shouldn't have to go beyond 6).  If
>> you get sawtoothing at the poles or faceting artifacts in the resulting
>> texture, then it means your smoothing parameters are not set correctly.
>> The
>> reason for using NURBS over polygons is the better interpolation of the
>> shading normal between texels.  Rendermap is highly dependent on the
>> shading
>> normal orientation to determine what it's camera points at.  When
>> pointing a
>> camera into the outside world, even very tiny deviations in normal
>> orientation can produce big errors in the result.  NURBS are infinitely
>> smooth whereas polygons are only as smooth as they are subdivided - and
>> even

Re: equirectangular uv

[pedro santos]

Does this help?
https://gfycat.com/ShabbySeriousDrafthorse

On Sun, May 15, 2016 at 7:02 AM, Matt Lind  wrote:

> I would need to see the problem to give a good answer as I'm not sure what
> I'm envisioning in my head matches what is being described.
>
> Knowing how the sphere is modified is important.  Unfold tries to evenly
> distribute the texture space of the texture to match the topology while
> minimizing stretch/compression.   If the poles have elongated triangles,
> then that will obviously play into the distribution of the unfolded texture
> (in theory it shouldn't, but in practice it does).  One way to mitigate
> that
> issue is to add vertices and perpendicular edges at regular intervals along
> the elongated edges to closely match the spacing of other edges around the
> rest of the mesh, but that will have limited influence on the result and is
> more of a brute force technique.
>
> Unfold is also a flawed tool as even simple cases come out distorted.  for
> example, get a primitive sphere and imagine it's the Earth.  Place a
> vertical UV seam down one side at the international date line, then two
> more
> seams at the arctic/antarctic circles.  Deselect the vertical edges
> connecting the circles to the poles.  Now unfold the mesh.  Notice the
> sphere is splayed in butterfly fashion, but one half is larger than the
> other and slightly off kilter in alignment with the texture editor.  The
> circle at one pole is often (but not always) larger than the other circle
> too.  These are the kinds of issues you'll battle, but on more complex
> cases
> they'll be too complex to solve without resorting to cleanup via
> pushing/pulling points to correct the flawed parts of the unfold.
>
> However, let's put all that aside and look at the goal from the beginning
> and not the current situation which has a roadblock.
>
> An equirectangular projection comes in a few flavors, but most are similar
> to a cubic projection.  The main difference is in how the top and bottom
> sides are projected.  Simple analysis of the problem would suggest one
> could
> take a cube and use Catmull-Clark subdivision smoothing to round it into a
> sphere.  That would accomplish nicer edge placement which closely match the
> meridians of the projection to handle (or fabricate) the texture space.  A
> single vertical seam from pole to pole (despite no physical poles) could be
> used to unfold and splay the sphere to accept/define the projection, but
> subtle details may need to be tweaked for a perfect match.
>
> Alternately, use rendermap applied to a sphere to capture the external
> world.  The rendermap generated image should mimic an equirectangular
> projection. You may have to open the poles like the Earth without the
> arctic/antarctic circles, for example, to adjust the field of view for the
> rendermap process.  Invert the sphere's normals so rendermap points
> outwards
> into the world instead of inwards towards the sphere's surfaceand of
> course, exclude self or make the material 100% transparent so it doesn't
> block the rendermap camera from seeing the world.  Since rendermap travels
> texel-to-texel along the geometry, a high resolution image and smooth
> surface are really important.  I'd encourage you to use a NURBS sphere with
> view dependent smoothing for best results.  you set those in the sphere's
> geometry approximations PPG.  Try setting length/distance/angle values to
> less than 2 degrees and 0.5 units, activate view dependent subdivision
> smoothing, and make sure the min/max subdivision limits are increased
> beyond
> the default 1,3 (well, just the max.  shouldn't have to go beyond 6).  If
> you get sawtoothing at the poles or faceting artifacts in the resulting
> texture, then it means your smoothing parameters are not set correctly.
> The
> reason for using NURBS over polygons is the better interpolation of the
> shading normal between texels.  Rendermap is highly dependent on the
> shading
> normal orientation to determine what it's camera points at.  When pointing
> a
> camera into the outside world, even very tiny deviations in normal
> orientation can produce big errors in the result.  NURBS are infinitely
> smooth whereas polygons are only as smooth as they are subdivided - and
> even
> then approximations at best.
>
> Matt
>
>
>
>
> Date: Sat, 14 May 2016 17:33:32 +0200
> From: "Sven Constable" 
> Subject: RE: equirectangular uv
> To: 
>
> To fix distortion on the poles, XSI has a special mapping feature called
> 'implicit' (Clusters/?Texture Projection Def), but this is actually a
> mental
> ray feature and doesn't deal with UVs at al

RE: equirectangular uv

[Matt Lind]

I would need to see the problem to give a good answer as I'm not sure what 
I'm envisioning in my head matches what is being described.

Knowing how the sphere is modified is important.  Unfold tries to evenly 
distribute the texture space of the texture to match the topology while 
minimizing stretch/compression.   If the poles have elongated triangles, 
then that will obviously play into the distribution of the unfolded texture 
(in theory it shouldn't, but in practice it does).  One way to mitigate that 
issue is to add vertices and perpendicular edges at regular intervals along 
the elongated edges to closely match the spacing of other edges around the 
rest of the mesh, but that will have limited influence on the result and is 
more of a brute force technique.

Unfold is also a flawed tool as even simple cases come out distorted.  for 
example, get a primitive sphere and imagine it's the Earth.  Place a 
vertical UV seam down one side at the international date line, then two more 
seams at the arctic/antarctic circles.  Deselect the vertical edges 
connecting the circles to the poles.  Now unfold the mesh.  Notice the 
sphere is splayed in butterfly fashion, but one half is larger than the 
other and slightly off kilter in alignment with the texture editor.  The 
circle at one pole is often (but not always) larger than the other circle 
too.  These are the kinds of issues you'll battle, but on more complex cases 
they'll be too complex to solve without resorting to cleanup via 
pushing/pulling points to correct the flawed parts of the unfold.

However, let's put all that aside and look at the goal from the beginning 
and not the current situation which has a roadblock.

An equirectangular projection comes in a few flavors, but most are similar 
to a cubic projection.  The main difference is in how the top and bottom 
sides are projected.  Simple analysis of the problem would suggest one could 
take a cube and use Catmull-Clark subdivision smoothing to round it into a 
sphere.  That would accomplish nicer edge placement which closely match the 
meridians of the projection to handle (or fabricate) the texture space.  A 
single vertical seam from pole to pole (despite no physical poles) could be 
used to unfold and splay the sphere to accept/define the projection, but 
subtle details may need to be tweaked for a perfect match.

Alternately, use rendermap applied to a sphere to capture the external 
world.  The rendermap generated image should mimic an equirectangular 
projection. You may have to open the poles like the Earth without the 
arctic/antarctic circles, for example, to adjust the field of view for the 
rendermap process.  Invert the sphere's normals so rendermap points outwards 
into the world instead of inwards towards the sphere's surfaceand of 
course, exclude self or make the material 100% transparent so it doesn't 
block the rendermap camera from seeing the world.  Since rendermap travels 
texel-to-texel along the geometry, a high resolution image and smooth 
surface are really important.  I'd encourage you to use a NURBS sphere with 
view dependent smoothing for best results.  you set those in the sphere's 
geometry approximations PPG.  Try setting length/distance/angle values to 
less than 2 degrees and 0.5 units, activate view dependent subdivision 
smoothing, and make sure the min/max subdivision limits are increased beyond 
the default 1,3 (well, just the max.  shouldn't have to go beyond 6).  If 
you get sawtoothing at the poles or faceting artifacts in the resulting 
texture, then it means your smoothing parameters are not set correctly.  The 
reason for using NURBS over polygons is the better interpolation of the 
shading normal between texels.  Rendermap is highly dependent on the shading 
normal orientation to determine what it's camera points at.  When pointing a 
camera into the outside world, even very tiny deviations in normal 
orientation can produce big errors in the result.  NURBS are infinitely 
smooth whereas polygons are only as smooth as they are subdivided - and even 
then approximations at best.

Matt




Date: Sat, 14 May 2016 17:33:32 +0200
From: "Sven Constable" 
Subject: RE: equirectangular uv
To: 

To fix distortion on the poles, XSI has a special mapping feature called 
'implicit' (Clusters/?Texture Projection Def), but this is actually a mental 
ray feature and doesn't deal with UVs at all. So when exporting meshes you 
cannot use it, I think. I'm not familiar with Unity unfortunatly, maybe 
there is a similar feature for spherical projections not using UVs but 
instead a special projection method (perfect spherical) ?

Otherwise, since a sphere always has poles/singularities you will get 
distortions on them. Workaround could get rid of the poles by deleting the 
inmost polygons on each pole, duplicating the resulting (open) edge loop, 
and scale it t

Re: equirectangular uv

[Francisco Criado]

Sven!

Sorry for the late reply, already did the same jejej, just was looking
(innecesary) a more detailed way for unwraping the sphere...i think its
beacuse of having half of my brain on the unity scripting editor :S
Cheers,

Francisco.

2016-05-14 12:54 GMT-03:00 Sven Constable :

> Just did a test:
>
>
>
> Apply a spherical projection. Delete the inmost polygons on the pole,
> duplicate the resulting edge loop, scale it to zero. Move it up in the TE.
> :)
>
>
>
>
>
>
>
> *From:* softimage-boun...@listproc.autodesk.com [mailto:
> softimage-boun...@listproc.autodesk.com] *On Behalf Of *Sven Constable
> *Sent:* Saturday, May 14, 2016 5:34 PM
> *To:* softimage@listproc.autodesk.com
> *Subject:* RE: equirectangular uv
>
>
>
> To fix distortion on the poles, XSI has a special mapping feature called
> 'implicit' (Clusters/…Texture Projection Def), but this is actually a
> mental ray feature and doesn't deal with UVs at all. So when exporting
> meshes you cannot use it, I think. I'm not familiar with Unity
> unfortunatly, maybe there is a similar feature for spherical projections
> not using UVs but instead a special projection method (perfect spherical) ?
>
> Otherwise, since a sphere always has poles/singularities you will get
> distortions on them. Workaround could get rid of the poles by deleting the
> inmost polygons on each pole, duplicating the resulting (open) edge loop,
> and scale it to zero. Resulting in many point on the same spot. Then
> relaxing them in the texture editor. Results could be ok, not sure. Maybe
> I'm  overcomplicating it.  Matt Lind needs to chime in :)
>
> Can't you use cubic mapping? That should avoid the problem in the first
> place.
>
>
>
> sven
>
>
>
>
>
> *From:* softimage-boun...@listproc.autodesk.com [
> mailto:softimage-boun...@listproc.autodesk.com
> ] *On Behalf Of *Francisco Criado
> *Sent:* Saturday, May 14, 2016 4:30 PM
> *To:* softimage@listproc.autodesk.com
> *Subject:* Re: equirectangular uv
>
>
>
> Hi Sven,
>
> Tried to use spherical projection for mapping but get usual distortion on
> the poles, and since i need to export the sphere to unity for mapping 360
> it has to be perfect.
>
> Cheers,
>
> Francisco
>
>
>
> 2016-05-14 10:49 GMT-03:00 Sven Constable :
>
> Sorry, if I'm misunderstanding your question, but don't you need just a
> spherical projection using a equirectangular image?
>
> sven
>
>
>
> *From:* softimage-boun...@listproc.autodesk.com [mailto:
> softimage-boun...@listproc.autodesk.com] *On Behalf Of *Francisco Criado
> *Sent:* Saturday, May 14, 2016 3:17 PM
> *To:* softimage@listproc.autodesk.com
> *Subject:* equirectangular uv
>
>
>
> Hi guys,
>
>
>
> i have a modified sphere on the poles, and tried using unfold to get a uv
> equirectangular projection. Its been a while since using softimage for uv
> work so maybe i have the answer just in front of me without notice.
>
> Any tips for achieving this?
>
> Thanks in advance!
>
>
>
> Francisco.
>
>
>
> --
>
>
>
>
> --
> Softimage Mailing List.
> To unsubscribe, send a mail to softimage-requ...@listproc.autodesk.com
> with "unsubscribe" in the subject, and reply to confirm.
>
>
>
>
> --
>
>
>
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> with "unsubscribe" in the subject, and reply to confirm.
>



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RE: equirectangular uv

[Sven Constable]

Just did a test:

 

Apply a spherical projection. Delete the inmost polygons on the pole, duplicate 
the resulting edge loop, scale it to zero. Move it up in the TE. :)  

 

 

 

From: softimage-boun...@listproc.autodesk.com 
[mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Sven Constable
Sent: Saturday, May 14, 2016 5:34 PM
To: softimage@listproc.autodesk.com
Subject: RE: equirectangular uv

 

To fix distortion on the poles, XSI has a special mapping feature called 
'implicit' (Clusters/…Texture Projection Def), but this is actually a mental 
ray feature and doesn't deal with UVs at all. So when exporting meshes you 
cannot use it, I think. I'm not familiar with Unity unfortunatly, maybe there 
is a similar feature for spherical projections not using UVs but instead a 
special projection method (perfect spherical) ?

Otherwise, since a sphere always has poles/singularities you will get 
distortions on them. Workaround could get rid of the poles by deleting the 
inmost polygons on each pole, duplicating the resulting (open) edge loop, and 
scale it to zero. Resulting in many point on the same spot. Then relaxing them 
in the texture editor. Results could be ok, not sure. Maybe I'm  
overcomplicating it.  Matt Lind needs to chime in :)

Can't you use cubic mapping? That should avoid the problem in the first place.

 

sven 

 

 

From: softimage-boun...@listproc.autodesk.com 
[mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Francisco Criado
Sent: Saturday, May 14, 2016 4:30 PM
To: softimage@listproc.autodesk.com
Subject: Re: equirectangular uv

 

Hi Sven,

Tried to use spherical projection for mapping but get usual distortion on the 
poles, and since i need to export the sphere to unity for mapping 360 it has to 
be perfect.

Cheers,

Francisco

 

2016-05-14 10:49 GMT-03:00 Sven Constable :

Sorry, if I'm misunderstanding your question, but don't you need just a 
spherical projection using a equirectangular image? 

sven

 

From: softimage-boun...@listproc.autodesk.com 
[mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Francisco Criado
Sent: Saturday, May 14, 2016 3:17 PM
To: softimage@listproc.autodesk.com
Subject: equirectangular uv

 

Hi guys,

 

i have a modified sphere on the poles, and tried using unfold to get a uv 
equirectangular projection. Its been a while since using softimage for uv work 
so maybe i have the answer just in front of me without notice. 

Any tips for achieving this?

Thanks in advance!

 

Francisco.


 

-- 

  
<https://docs.google.com/uc?export=download&id=0BwaBYuN-wyXqdEtjOFEyRlVUTm8&revid=0BwaBYuN-wyXqakNjc3BJWEM1ZlpBRXoyaEVuNHFESGcyVDQ4PQ>
 

 


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RE: equirectangular uv

[Sven Constable]

To fix distortion on the poles, XSI has a special mapping feature called 
'implicit' (Clusters/…Texture Projection Def), but this is actually a mental 
ray feature and doesn't deal with UVs at all. So when exporting meshes you 
cannot use it, I think. I'm not familiar with Unity unfortunatly, maybe there 
is a similar feature for spherical projections not using UVs but instead a 
special projection method (perfect spherical) ?

Otherwise, since a sphere always has poles/singularities you will get 
distortions on them. Workaround could get rid of the poles by deleting the 
inmost polygons on each pole, duplicating the resulting (open) edge loop, and 
scale it to zero. Resulting in many point on the same spot. Then relaxing them 
in the texture editor. Results could be ok, not sure. Maybe I'm  
overcomplicating it.  Matt Lind needs to chime in :)

Can't you use cubic mapping? That should avoid the problem in the first place.

 

sven 

 

 

From: softimage-boun...@listproc.autodesk.com 
[mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Francisco Criado
Sent: Saturday, May 14, 2016 4:30 PM
To: softimage@listproc.autodesk.com
Subject: Re: equirectangular uv

 

Hi Sven,

Tried to use spherical projection for mapping but get usual distortion on the 
poles, and since i need to export the sphere to unity for mapping 360 it has to 
be perfect.

Cheers,

Francisco

 

2016-05-14 10:49 GMT-03:00 Sven Constable :

Sorry, if I'm misunderstanding your question, but don't you need just a 
spherical projection using a equirectangular image? 

sven

 

From: softimage-boun...@listproc.autodesk.com 
[mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Francisco Criado
Sent: Saturday, May 14, 2016 3:17 PM
To: softimage@listproc.autodesk.com
Subject: equirectangular uv

 

Hi guys,

 

i have a modified sphere on the poles, and tried using unfold to get a uv 
equirectangular projection. Its been a while since using softimage for uv work 
so maybe i have the answer just in front of me without notice. 

Any tips for achieving this?

Thanks in advance!

 

Francisco.


 

-- 

  
<https://docs.google.com/uc?export=download&id=0BwaBYuN-wyXqdEtjOFEyRlVUTm8&revid=0BwaBYuN-wyXqakNjc3BJWEM1ZlpBRXoyaEVuNHFESGcyVDQ4PQ>
 

 


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Re: equirectangular uv

[Francisco Criado]

Hi Sven,

Tried to use spherical projection for mapping but get usual distortion on
the poles, and since i need to export the sphere to unity for mapping 360
it has to be perfect.

Cheers,
Francisco

2016-05-14 10:49 GMT-03:00 Sven Constable :

> Sorry, if I'm misunderstanding your question, but don't you need just a
> spherical projection using a equirectangular image?
>
> sven
>
>
>
> *From:* softimage-boun...@listproc.autodesk.com [mailto:
> softimage-boun...@listproc.autodesk.com] *On Behalf Of *Francisco Criado
> *Sent:* Saturday, May 14, 2016 3:17 PM
> *To:* softimage@listproc.autodesk.com
> *Subject:* equirectangular uv
>
>
>
> Hi guys,
>
>
>
> i have a modified sphere on the poles, and tried using unfold to get a uv
> equirectangular projection. Its been a while since using softimage for uv
> work so maybe i have the answer just in front of me without notice.
>
> Any tips for achieving this?
>
> Thanks in advance!
>
>
>
> Francisco.
>
>
>
> --
>
>
>
> --
> Softimage Mailing List.
> To unsubscribe, send a mail to softimage-requ...@listproc.autodesk.com
> with "unsubscribe" in the subject, and reply to confirm.
>



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"unsubscribe" in the subject, and reply to confirm.

RE: equirectangular uv

[Sven Constable]

Sorry, if I'm misunderstanding your question, but don't you need just a 
spherical projection using a equirectangular image? 

sven

 

From: softimage-boun...@listproc.autodesk.com 
[mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Francisco Criado
Sent: Saturday, May 14, 2016 3:17 PM
To: softimage@listproc.autodesk.com
Subject: equirectangular uv

 

Hi guys,

 

i have a modified sphere on the poles, and tried using unfold to get a uv 
equirectangular projection. Its been a while since using softimage for uv work 
so maybe i have the answer just in front of me without notice. 

Any tips for achieving this?

Thanks in advance!

 

Francisco.


 

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