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6:19 p.m.
Hi,
Anyone dealt with this? Any pointers appreciated! I sure wish
Houdini's camera was compatible with the rest of the world :(
Here is the problem we are seeing. When a camera is sent via FBX from
maya to Houdini the filmback
values are changed to an aperture value.
Then when the camera is exported via FBX from Houdini to Nuke or back
to Maya the values are
different.
Below are the numbers we are using/seeing:
Actual filmback:
0.882" (22.4mm) x 0.496" (12.598mm)
Image resolution:
1920x1080
Maya to Nuke is good
Maya to Houdini:
Houdini converts the filmback values to 16.7979 (aperture)
Houdini to Nuke = different values: 0.661" x 0.372
Houdini back to Maya = 0.661 x 0.372
Cheers,
--
No, I am not on Facebook.

6:57 p.m.
Hi Peter,
I remember Miles had a Houdini-Maya camera exchange tool on his site.
I haven't had the chance to try it myself but as I know Miles it's gonna be
solid.
It might not be the "all around" solution for you as it doesn't seem to
support Nuke out of the box, but it should get you around the problems you
are facing.
www.houdinistuff.com
and maybe this is of interest for you too:
http://animbyu.groups.et.byu.net/wiki/index.php?title=Houdini_and_Maya
hope it helps
cheers
Ron
Ron Schab
-----------------------------------------------------------------------
http://www.linkedin.com/in/ronschab
http://www.xing.com/profile/ron_schab
http://www.xing.com/go/invita/4525868
GER:+49 (0)1577 - 4096084
UK: +44 (0)7511 295510
AUS: +61 (0)449 136336
NZ: +64 (0)21 0754 597
Kuala Lumpur:+60 133969400
On Sat, Sep 25, 2010 at 08:19, Peter Bowmar <pbowmar at gmail.com> wrote:
Hi,
Anyone dealt with this? Any pointers appreciated! I sure wish
Houdini's camera was compatible with the rest of the world :(
Here is the problem we are seeing. When a camera is sent via FBX from
maya to Houdini the filmback
values are changed to an aperture value.
Then when the camera is exported via FBX from Houdini to Nuke or back
to Maya the values are
different.
Below are the numbers we are using/seeing:
Actual filmback:
0.882" (22.4mm) x 0.496" (12.598mm)
Image resolution:
1920x1080
Maya to Nuke is good
Maya to Houdini:
Houdini converts the filmback values to 16.7979 (aperture)
Houdini to Nuke = different values: 0.661" x 0.372
Houdini back to Maya = 0.661 x 0.372
Cheers,
--
No, I am not on Facebook.
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

7:12 p.m.
Houdini's camera is fine. It uses identical values to Nuke and plays well
with prman as well. Maya is the odd one out from that group. That thing is a
nasty piece of work. Just pray people are using the horizontal fit. It gets
more nasty otherwise. In any case it sounds like your problem is in the FBX
exporter for Houdini (SESI!?). If you really need to go from Houdini to Nuke
a lot you may be better off not using FBX and just going direct from Houdini
to Nuke. It's not that hard to do the string formatting involved in that
converter.
I should point out that getting soho to match the maya FOV is another drama
that most converters miss - but is essential if renderer integration with
perfect registration is a goal. This is how Maya does it:
proc float AEcalculateFOV( string $focalStr, string $horStr )
{
float $focal = `getAttr $focalStr`;
float $aperture = `getAttr $horStr`;
float $fov = (0.5 * $aperture) / ($focal * 0.03937); // mm2inch rounded
down arbitrarily
$fov = 2.0 * atan ($fov);
$fov = 57.29578 * $fov;
return $fov;
}
You can hopefully reverse engineer the soho fov code needed to match that.
It's kind of nasty. You have to use the houdini focal and aperture settings
to reverse engineer the focal that maya uses with the approximate values of
mm2 inch etc, and then use that slightly wrong focal instead of the original
clean Houdini focal. It does give perfect registration with Maya renders
though. SESI don't ship that hack with FBX or soho, and I haven't seen it
mentioned on the web anywhere...
Cheers
On 24 September 2010 15:57, Ron Schab <ron.schab at gmail.com> wrote:
Hi Peter,
I remember Miles had a Houdini-Maya camera exchange tool on his site.
I haven't had the chance to try it myself but as I know Miles it's gonna be
solid.
It might not be the "all around" solution for you as it doesn't seem to
support Nuke out of the box, but it should get you around the problems you
are facing.
www.houdinistuff.com
and maybe this is of interest for you too:
http://animbyu.groups.et.byu.net/wiki/index.php?title=Houdini_and_Maya
hope it helps
cheers
Ron
Ron Schab
-----------------------------------------------------------------------
http://www.linkedin.com/in/ronschab
http://www.xing.com/profile/ron_schab
http://www.xing.com/go/invita/4525868
GER:+49 (0)1577 - 4096084
UK: +44 (0)7511 295510
AUS: +61 (0)449 136336
NZ: +64 (0)21 0754 597
Kuala Lumpur:+60 133969400
On Sat, Sep 25, 2010 at 08:19, Peter Bowmar <pbowmar at gmail.com> wrote:
> Hi,
>
> Anyone dealt with this? Any pointers appreciated! I sure wish
> Houdini's camera was compatible with the rest of the world :(
>
> Here is the problem we are seeing. When a camera is sent via FBX from
> maya to Houdini the filmback
> values are changed to an aperture value.
> Then when the camera is exported via FBX from Houdini to Nuke or back
> to Maya the values are
> different.
>
> Below are the numbers we are using/seeing:
>
>
> Actual filmback:
> 0.882" (22.4mm) x 0.496" (12.598mm)
>
> Image resolution:
> 1920x1080
>
>
> Maya to Nuke is good
>
> Maya to Houdini:
> Houdini converts the filmback values to 16.7979 (aperture)
>
> Houdini to Nuke = different values: 0.661" x 0.372
> Houdini back to Maya = 0.661 x 0.372
>
> Cheers,
> --
> No, I am not on Facebook.
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
--
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================

7:33 p.m.
Thanks guys, it turns out that it's mostly FBX not putting all data
into the FBX file, or Houdini's importer not reading it (haven't
figured that one out yet) but when you import FBX it doesn't set the
cam res and that of course screws up the aspect ratio. Problem sorted!
Cheers,
Peter B
On 24 September 2010 16:12, Andrew D Lyons <tstexture at gmail.com> wrote:
Houdini's camera is fine. It uses identical values to Nuke and
plays well
with prman as well. Maya is the odd one out from that group. That thing is a
nasty piece of work. Just pray people are using the horizontal fit. It gets
more nasty otherwise. In any case it sounds like your problem is in the FBX
exporter for Houdini (SESI!?). If you really need to go from Houdini to Nuke
a lot you may be better off not using FBX and just going direct from Houdini
to Nuke. It's not that hard to do the string formatting involved in that
converter.
I should point out that getting soho to match the maya FOV is another drama
that most converters miss - but is essential if renderer integration with
perfect registration is a goal. This is how Maya does it:
proc float AEcalculateFOV( string $focalStr, string $horStr )
{
? ?float $focal = `getAttr $focalStr`;
? ?float $aperture = `getAttr $horStr`;
? ?float $fov = (0.5 * $aperture) / ($focal * 0.03937); // mm2inch rounded
down arbitrarily
? ?$fov = 2.0 * atan ($fov);
? ?$fov = 57.29578 * $fov;
? ?return $fov;
}
You can hopefully reverse engineer the soho fov code needed to match that.
It's kind of nasty. You have to use the houdini focal and aperture settings
to reverse engineer the focal that maya uses with the approximate values of
mm2 inch etc, and then use that slightly wrong focal instead of the original
clean Houdini focal. It does give perfect registration with Maya renders
though. SESI don't ship that hack with FBX or soho, and I haven't seen it
mentioned on the web anywhere...
Cheers
On 24 September 2010 15:57, Ron Schab <ron.schab at gmail.com> wrote:
> Hi Peter,
>
> I remember Miles had a Houdini-Maya camera exchange tool on his site.
> I haven't had the chance to try it myself but as I know Miles it's gonna be
> solid.
> It might not be the "all around" solution for you as it doesn't seem
to
> support Nuke out of the box, but it should get you around the problems you
> are facing.
>
> www.houdinistuff.com
>
> and maybe this is of interest for you too:
>
> http://animbyu.groups.et.byu.net/wiki/index.php?title=Houdini_and_Maya
>
>
>
> hope it helps
> cheers
> Ron
>
>
> Ron Schab
> -----------------------------------------------------------------------
>
> http://www.linkedin.com/in/ronschab
>
> http://www.xing.com/profile/ron_schab
> http://www.xing.com/go/invita/4525868
>
> GER:+49 (0)1577 - 4096084
> UK: +44 (0)7511 295510
> AUS: +61 (0)449 136336
> NZ: +64 (0)21 0754 597
> Kuala Lumpur:+60 133969400
>
>
> On Sat, Sep 25, 2010 at 08:19, Peter Bowmar <pbowmar at gmail.com> wrote:
>
> > Hi,
> >
> > Anyone dealt with this? Any pointers appreciated! I sure wish
> > Houdini's camera was compatible with the rest of the world :(
> >
> > Here is the problem we are seeing. ?When a camera is sent via FBX from
> > maya to Houdini the filmback
> > values are changed to an aperture value.
> > Then when the camera is exported via FBX from Houdini to Nuke or back
> > to Maya the values are
> > different.
> >
> > Below are the numbers we are using/seeing:
> >
> >
> > Actual filmback:
> > 0.882" (22.4mm) x 0.496" (12.598mm)
> >
> > Image resolution:
> > 1920x1080
> >
> >
> > Maya to Nuke is good
> >
> > Maya to Houdini:
> > Houdini converts the filmback values to 16.7979 (aperture)
> >
> > Houdini to Nuke = different values: 0.661" x 0.372
> > Houdini back to Maya = 0.661 x 0.372
> >
> > Cheers,
> > --
> > No, I am not on Facebook.
> > _______________________________________________
> > Sidefx-houdini-list mailing list
> > Sidefx-houdini-list at sidefx.com
> > https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> >
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>
--
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
--
No, I am not on Facebook.

1:33 p.m.
FYI, if you run into this into the future, here is the quick work-around hack.
Lay down a bog-standard Houdini cam. Change the resolution to the known desired
resolution, (EX: 1920 x 1080). Save as permanent default. Now import your FBX camera.
Everything will be fine, you can then export to Nuke/Maya and you'll have the same
camera.
Seems resolution is not written into the FBX file.
Sean
-----Original Message-----
From: sidefx-houdini-list-bounces at sidefx.com [mailto:sidefx-houdini-list-bounces at
sidefx.com] On Behalf Of Peter Bowmar
Sent: Friday, September 24, 2010 4:33 PM
To: sidefx-houdini-list at sidefx.com
Subject: Re: [Sidefx-houdini-list] Cam back to aperture Maya/Nuke/Houdini
Thanks guys, it turns out that it's mostly FBX not putting all data
into the FBX file, or Houdini's importer not reading it (haven't
figured that one out yet) but when you import FBX it doesn't set the
cam res and that of course screws up the aspect ratio. Problem sorted!
Cheers,
Peter B
On 24 September 2010 16:12, Andrew D Lyons <tstexture at gmail.com> wrote:
Houdini's camera is fine. It uses identical values to Nuke and
plays well
with prman as well. Maya is the odd one out from that group. That thing is a
nasty piece of work. Just pray people are using the horizontal fit. It gets
more nasty otherwise. In any case it sounds like your problem is in the FBX
exporter for Houdini (SESI!?). If you really need to go from Houdini to Nuke
a lot you may be better off not using FBX and just going direct from Houdini
to Nuke. It's not that hard to do the string formatting involved in that
converter.
I should point out that getting soho to match the maya FOV is another drama
that most converters miss - but is essential if renderer integration with
perfect registration is a goal. This is how Maya does it:
proc float AEcalculateFOV( string $focalStr, string $horStr )
{
float $focal = `getAttr $focalStr`;
float $aperture = `getAttr $horStr`;
float $fov = (0.5 * $aperture) / ($focal * 0.03937); // mm2inch rounded
down arbitrarily
$fov = 2.0 * atan ($fov);
$fov = 57.29578 * $fov;
return $fov;
}
You can hopefully reverse engineer the soho fov code needed to match that.
It's kind of nasty. You have to use the houdini focal and aperture settings
to reverse engineer the focal that maya uses with the approximate values of
mm2 inch etc, and then use that slightly wrong focal instead of the original
clean Houdini focal. It does give perfect registration with Maya renders
though. SESI don't ship that hack with FBX or soho, and I haven't seen it
mentioned on the web anywhere...
Cheers
On 24 September 2010 15:57, Ron Schab <ron.schab at gmail.com> wrote:
> Hi Peter,
>
> I remember Miles had a Houdini-Maya camera exchange tool on his site.
> I haven't had the chance to try it myself but as I know Miles it's gonna be
> solid.
> It might not be the "all around" solution for you as it doesn't seem
to
> support Nuke out of the box, but it should get you around the problems you
> are facing.
>
> www.houdinistuff.com
>
> and maybe this is of interest for you too:
>
> http://animbyu.groups.et.byu.net/wiki/index.php?title=Houdini_and_Maya
>
>
>
> hope it helps
> cheers
> Ron
>
>
> Ron Schab
> -----------------------------------------------------------------------
>
> http://www.linkedin.com/in/ronschab
>
> http://www.xing.com/profile/ron_schab
> http://www.xing.com/go/invita/4525868
>
> GER:+49 (0)1577 - 4096084
> UK: +44 (0)7511 295510
> AUS: +61 (0)449 136336
> NZ: +64 (0)21 0754 597
> Kuala Lumpur:+60 133969400
>
>
> On Sat, Sep 25, 2010 at 08:19, Peter Bowmar <pbowmar at gmail.com> wrote:
>
> > Hi,
> >
> > Anyone dealt with this? Any pointers appreciated! I sure wish
> > Houdini's camera was compatible with the rest of the world :(
> >
> > Here is the problem we are seeing. When a camera is sent via FBX from
> > maya to Houdini the filmback
> > values are changed to an aperture value.
> > Then when the camera is exported via FBX from Houdini to Nuke or back
> > to Maya the values are
> > different.
> >
> > Below are the numbers we are using/seeing:
> >
> >
> > Actual filmback:
> > 0.882" (22.4mm) x 0.496" (12.598mm)
> >
> > Image resolution:
> > 1920x1080
> >
> >
> > Maya to Nuke is good
> >
> > Maya to Houdini:
> > Houdini converts the filmback values to 16.7979 (aperture)
> >
> > Houdini to Nuke = different values: 0.661" x 0.372
> > Houdini back to Maya = 0.661 x 0.372
> >
> > Cheers,
> > --
> > No, I am not on Facebook.
> > _______________________________________________
> > Sidefx-houdini-list mailing list
> > Sidefx-houdini-list at sidefx.com
> > https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> >
> _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
>
--
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================
_______________________________________________
Sidefx-houdini-list mailing list
Sidefx-houdini-list at sidefx.com
https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
--
No, I am not on Facebook.
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