Hi ,

Just as a test, I made a file of a cube and a cylinder for a CSG test in
sPatch, then exported to Moray. Following were the results:
On differencing the cylinder from the cube, the results were perfectly (I
think) displayed in the opengl 3d view, but drew a blank in PovRay
rendering. BUT, the same thing rendered with (so far) simple texturising,
using the scanline option of the anim-plugin.
Can anybody explain this? I can understand the csg not showing in PovRay
(bicubic patches etc) but why, then, did it show in the opengl interface
and in the scanline rendering. Also, could it not be replicated in PovRay?
(This would allow us to use it's other macros/advanced features)
Also, this is a bit OT, when I directly export to Megapov from sPatch
(pigmesh - mesh with smooth_triangles), enable solid mesh features (using
inside_vector) all I get is 'intersection'. Why?
Thanks for any help in advance

-Anoop

P.S. Would be very nice if Moray could export to sPatch/HamaPatch, wouldn't
it? They both complement each other almost perfectly, what with the csg,
perfect PovRay interface of one, and the splines & vertex editing & lofting
(in HP, using AMLoft) of the other. (Not to mention that HamaPatch also
exports to BMRT, allowing the use of it's true displacement-mapping
features.) Any chance??

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>the same thing rendered with (so far) simple texturising,
> using the scanline option of the anim-plugin.
> Can anybody explain this? I can understand the csg not showing in PovRay
> (bicubic patches etc) but why, then, did it show in the opengl interface
> and in the scanline rendering. Also, could it not be replicated in PovRay?

If I've got this correct then scanline rendering and the opengl views use a
different 'concept' to display the image.  POV-Ray is a raytracer and so
works by shooting samples and calculating whats what at that position.  Lutz
has built the OpenGl using a different idea (scanline type?) similar to the
scanline render in which is sees all objects as polygon meshes and displays
them accordingly.

In effect Moray shows how it thinks (correctly though) the scene will look
in POV-Ray using a different method... or have I got something wrong?


Peter Cracknell
http://www.petercracknell.com


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Peter Cracknell wrote in message <3b112539@news.povray.org>...

>If I've got this correct then scanline rendering and the opengl views use
a
>different 'concept' to display the image.  POV-Ray is a raytracer and so
>works by shooting samples and calculating whats what at that position.
Lutz
>has built the OpenGl using a different idea (scanline type?) similar to
the
>scanline render in which is sees all objects as polygon meshes and
displays
>them accordingly.
>

>Peter Cracknell
>http://www.petercracknell.com


Thank you. That does clear a lot (unfortunately?). Perhaps there is a way
around this using a third modeller.

-Anoop

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> Just as a test, I made a file of a cube and a cylinder for a CSG test in
> sPatch, then exported to Moray. Following were the results:
> On differencing the cylinder from the cube, the results were perfectly (I
> think) displayed in the opengl 3d view, but drew a blank in PovRay
> rendering. BUT, the same thing rendered with (so far) simple texturising,
> using the scanline option of the anim-plugin.
> Can anybody explain this? I can understand the csg not showing in PovRay
> (bicubic patches etc) but why, then, did it show in the opengl interface
> and in the scanline rendering. Also, could it not be replicated in PovRay?

I'll let you have my take on the subject.

To the best of my knowledge, POV is incapable of calculating CSG 
differences or merges using patches.

The Moray 3d preview works by reducing everything to triangles, and can 
thus predict (in this case, incorrectly) what it thinks the CSG would 
look like.

The Scanline option in the anim-plugin also reduces all objects to 
triangles before rendering.

Oh, and such an effect is unlikely to be implemented in POV until there 
is native support for tesselation of primitives.  But that's another 
subject.

Anybody out there want to shoot my theories down in flames?  Lutz?

:)

Bye for now,
     Jamie.

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Thanks for the reply. (Unfortunately) it confirms what Peter Cracknell
wrote, while making it even more understandable. Just a few thoughts
of my own:

Jamie Davison wrote in message ...
>I'll let you have my take on the subject.
>
>To the best of my knowledge, POV is incapable of calculating CSG
>differences or merges using patches...

>The Moray 3d preview works by reducing everything to triangles, and can
>thus predict (in this case, incorrectly) what it thinks the CSG would
>look like...

True. But Megapov *can* do CSGs using either the mesh or the mesh2
format.So, couldn't (and pardon me if I put my foot in my mouth through
ignorance) Moray export the *results* as a solid mesh (mesh/mesh2 with
'inside_vector ' enabled). I believe Peak3d does something similar.
Would this mean a major reworking? And wouldn't it be worth it, combining
the
power of both sPatch/ Hamapatch (especially now that you *can* do
lofts/skinning in HamaPatch using the AMexport/AMLoft utility?

Which brings me back to my second pt: Would there be a utility  which would
allow me to export to sPatch so that I can use the power of both. I really
would love to use Moray for my normal (architectural) work but it's lack of
spline support (& vertex editing) are discouraging. Otherwise, in many
ways, it is a truly wonderful program; especially int it's Pov-Ray
interface and handling of CSGs.

Sorry for rambling. And thanks again, both of you, for your clarifications.

Regards,
-Anoop

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[snip]
> True. But Megapov *can* do CSGs using either the mesh or the mesh2
> format.So, couldn't (and pardon me if I put my foot in my mouth through
> ignorance) Moray export the *results* as a solid mesh (mesh/mesh2 with
> 'inside_vector ' enabled). I believe Peak3d does something similar.
> Would this mean a major reworking? And wouldn't it be worth it, combining
> the
> power of both sPatch/ Hamapatch (especially now that you *can* do
> lofts/skinning in HamaPatch using the AMexport/AMLoft utility?

Moray is unlikely to ever support MegaPOV features, as it is written to 
be compliant with official POV only, and I suspect that that in itself is 
quite enough of a job for Lutz to handle.

Maybe after (the semi-mythical) POV 3.5 is released and Lutz has had 
enough time to work on its features, then something like that may happen, 
but I'm not going to hold my breath waiting. :)
 
[snip]
> Sorry for rambling. And thanks again, both of you, for your clarifications.

No problem.

Bye for now,
     Jamie.

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Hi Jamie Davison, you recently wrote in moray.win:

> Anybody out there want to shoot my theories down in flames?  Lutz?
I think betwenn you and Peter, we've got all bases covered :-)

- Lutz
  email : lut### [at] stmuccom
  Web   : http://www.stmuc.com/moray

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Hi Anoop Kumar, you recently wrote in moray.win:

> True. But Megapov *can* do CSGs using either the mesh or the mesh2
> format.
But a bezier patch is seldomly a solid object. I think MegaPOV can
handle CSG with patches (or triangles meshes for that matter) only if
they are closed (solid) objects. Otherwise there is no correct way of
displaying that.

> So, couldn't Moray export the *results* as a solid mesh 
But then Moray would be undoing exactly what it wants to avoid ->
turning everything into triangles. Moray is NOT a triangle modeller,
which is what is required to do any sort of vertex editing. In
POV-Ray/Moray there are no vertices to edit when you are working with
CSG. 

> Would this mean a major reworking? And wouldn't it be worth it, combining
> the power .....
That said, I do agree, however, that triangle modelling part of Moray
would be very useful in many ways. But look at the triangle modellers
out there, what they offer (and what they cost) and you can clearly
see that it's going to be a bit difficult to offer this as a part of
Moray....

> I really would love to use Moray for my normal (architectural) work
> but it's lack of spline support (& vertex editing) are discouraging. 
Hmmmm, I would have thought that architectural work is ideally suited
to using CSG.....

Regards,

- Lutz
  email : lut### [at] stmuccom
  Web   : http://www.stmuc.com/moray

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Lutz Kretzschmar wrote in message ...

>> So, couldn't Moray export the *results* as a solid mesh
>But then Moray would be undoing exactly what it wants to avoid ->
>turning everything into triangles. Moray is NOT a triangle modeller,
>which is what is required to do any sort of vertex editing. In
>POV-Ray/Moray there are no vertices to edit when you are working with
>CSG.
>> Would this mean a major reworking? And wouldn't it be worth it,
combining
>> the power .....
>That said, I do agree, however, that triangle modelling part of Moray
>would be very useful in many ways. But look at the triangle modellers
>out there, what they offer (and what they cost) and you can clearly
>see that it's going to be a bit difficult to offer this as a part of
>Moray....

That's true, Moray does offer a lot of value for it's cost. Unfortunately
some of it's values are different from mine:(

>> I really would love to use Moray for my normal (architectural) work
>> but it's lack of spline support (& vertex editing) are discouraging.
>Hmmmm, I would have thought that architectural work is ideally suited
>to using CSG.....

CSG is very important, but the normal mode of working would be somthing
like this: 1).import plan (splines) from CAD program (unless, like, say,
Rhino
it combines both precision with modelling ease); 2) extrude walls to proper
ht/loft wall section along plan; mesh/vertex-edit & difference your
inner-wall mass from the outer-wall mass. 3) CSG your window/doors etc.
Also
lofting would be very useful for making complicated sloped-roofs.

Talking of splines, would there be any proposal for making the translated
splines realtime? Also, perhaps, (translated) nested spline shapes (prisms)
as in Pov-Ray? This would make the modelling of ordinary (simple-section)
walls easier to do.

Lastly, (& most important), export to sPatch/HamaPatch. Between
the two of them (Moray & HamaPatch) practically all bases should be
covered, I feel.

Thanks again,

& Regards
-Anoop

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> That's true, Moray does offer a lot of value for it's cost. Unfortunately
> some of it's values are different from mine:(

I am finding that I use moray more and more for scene layout and texturing
rather than modelling, it really doesn't get any better than rhino - which
thankfully exports moray UDO :)


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