Re: Dosch HDRI maps

["Tim Leydecker" <BauerOink(at)gmx.de>]

Hi Andy,

sorry for the delayed response, I lost track.

Yeah, getting good UV´s on the sphere to rendermap from
has proven bitchy, I´ve still got some stretching at the poles
currently but decided to live with it for now.

Regarding the intensity shift, factor 2 or 4 are ballparkfigures
I´ll dial in to account for the fallof that seems to happen when
using the rendermapped file as source for the enviromentshader
together with FG. From a physically accurate POV one could
argue this "must be" correct, due to conversion happening from

light>rendermapshere>envshader>lit object

but this could also be a complete bogus and I had just set my
diffuse values wrong initially...


Cheers

tim

P.S: I just learned yesterday that at least Mayas materials have
a factor 3.14 (pi) too high defaultvalue for the diffuse, althought
the irradiance attribute has been fixed for mR (both XSI+Maya),
this seems to have slipped through, maybe something to do with that...


----- Original Message ----- 
From: "Andy Jones" <andy(at)thefront.com>
To: <XSI(at)Softimage.COM>
Sent: Saturday, September 16, 2006 11:38 PM
Subject: Re: Dosch HDRI maps


> Actually, now that you mention it, I don't know that I've ever generated a 32-bit 
> reflection map from scene geometry.  I have taken existing reflection maps and 
> blurred them using shaders and texture baking to allow for optimized convergence in 
> shaders that multi-sample the environment (since just blurring a reflection map 
> typically produces uneven blur).  I guess to do a straight-up reflection map, I 
> would probably just throw a reflection shader on a sphere and rendermap to a 
> spherical projection.  I suppose you could do a cubic cross, but AFAIK, you'd have 
> to do some manual uv'ing or something.  I think at one point, we wrote a script to 
> spherize an object, so you could cubic-project on a cube, then subdivide a bunch of 
> times and spherize it.  So you'd basically have a perfectly-cubically-divisible 
> sphere.  Otherwise, the edges aren't really in the right place, I think.  You could 
> also do a cubic map by rendering out 90 degree cameras in 6 directions -- I've done 
> that for quick&dirty GL stuff before.
> I think in the past, I've usually gone straight to .map, and then used the .map 
> files directly, without re-exposing.  I don't really see why you should have to 
> adjust for intensity in a general sense -- do you have any idea why that is?
>
> -Andy
>
>
>
> Tim Leydecker wrote:
>
> > Sorry, I´m using *.ct, not *.map. *.ct works.
> > Convert it using imf_disp.exe from a Maya install.
> > (XSI one will work the same or better,depends on build).
> >
> > Cheers
> >
> > tim
> >
> >
> > ----- Original Message ----- From: "Tim Leydecker" <BauerOink(at)gmx.de>
> > To: <XSI(at)Softimage.COM>
> > Sent: Saturday, September 16, 2006 10:11 AM
> > Subject: Re: Dosch HDRI maps
> >
> >
> > > How do you create your 32bit environmentmaps in xsi?
> > >
> > > custom shader? spherical ones or cubics?
> > >
> > > I currently bake a 100%reflective sphere to *.map texture
> > > and convert that to a *.hdr/*.exr since it seems using any
> > > other format produces incorrect results in XSI 5.1/5.11
> > > when selected a target for a baking. I think I logged it a bug
> > > allready, at least for *.exr. This approach lacks good
> > > filtering, thought. Also reuqires the resulting file to be
> > > normalized by factor 2 or 4 to get the proper intensity back.
> > >
> > > HDRshop is nice to have when comparing actual dynamic
> > > range of source and baked texture for such a matter and
> > > fitting the "intensity" to the former.
> > >
> > > Cheers
> > >
> > >
> > > tim
> > >
> > >
> > >
> > >
> > >
> > >
> > > ----- Original Message ----- From: <andy(at)thefront.com>
> > > To: <XSI(at)Softimage.COM>
> > > Sent: Saturday, September 16, 2006 7:26 AM
> > > Subject: Re: Dosch HDRI maps
> > >
> > >
> > > > This is good to know.  So, I won't raise my arms and scream if anyone
> > > > tries to buy the Extreme High Res ones or the skies (although I will
> > > > mention that we already own the skies).  I still highly recommend that
> > > > others do so if anyone tries to buy "radiant skies" or "industrial
> > > > reflections."
> > > >
> > > > The project we're working on right now requires interior lighting.  And
> > > > actually, we were hoping to relight each shot individually.  Does anyone
> > > > have any good tricks for getting nice "soft-box" effects in reflections? And has 
> > > > anyone used the stuff from HDRI-Studio with any success?  It seems
> > > > like what we'd really like to have is just a model of a soft-box with a
> > > > proper re-exposable exr texture that I could duplicate and place in a
> > > > scene, then generate my own exr environment maps from it (or just render
> > > > it directly).
> > > >
> > > > -Andy
> > > >
> > > > On Fri, September 15, 2006 3:59 pm, Francois Lord wrote:
> > > >
> > > > > The Extreme High Res ones are useful when you need an 360 degrees
> > > > > environment for an SD shot, or when you need very crisp reflections in HD.
> > > > > Creating your own HDR image with that quality is quite difficult.
> > > > > The skies are ok. It's definitely cheaper to buy them than to go out and
> > > > > try to get the right sky for the shot you need... for 14 days in a row.
> > > > >
> > > > > Kris Rivel wrote:
> > > > >
> > > > > > Well I can only speak on behalf of the "Extreme High Res" and standard
> > > > > > "Sky" libraries.  I found them very useful on several jobs where
> > > > > > creating or shooting our own HDRI was out of the question.  If you have
> > > > > > the time and money though, its worth making your own with a proper
> > > > > > setup.  I can highly recommend the guys at EPOP (http://www.epop.com/).
> > > > > > They use one of those great Spheron cameras
> > > > > > and they created stunning HDRI images for me in the past.
> > > > > >
> > > > > > Kris
> > > > > >
> > > > > >
> > > > > >
> > > > > > Andy Jones wrote:
> > > > > >
> > > > > > > Yeah, I suppose we have too, though we've had just as much luck just
> > > > > > > browsing through Turbo Squid.  But these exr's, specifically, are
> > > > > > > pretty weak, I think.
> > > > > > >
> > > > > > > -Andy
> > > > > > >
> > > > > > >
> > > > > > > Joe Laffey wrote:
> > > > > > >
> > > > > > >
> > > > > > > > On Thu, 14 Sep 2006, Andy Jones wrote:
> > > > > > > >
> > > > > > > >
> > > > > > > > > This is just an FYI for anyone who doesn't want to waste $125 or
> > > > > > > > > so.  This is now the third time one of our project leads has
> > > > > > > > > decided to buy a package of Dosch HDRI environment maps for a
> > > > > > > > > project.  We now own skies, radiant skies, and industrial
> > > > > > > > > reflections.  Of these, it's really obvious that radiant skies
> > > > > > > > > and industrial reflections are just CG renders of
> > > > > > > > > poorly-constructed environments.  In the industrial reflections,
> > > > > > > > > there are, for example, completely black materials (that don't
> > > > > > > > > ever change color no matter what exposure you use).  And none of
> > > > > > > > > the interior lighting re-exposes in any sort of reasonable way.
> > > > > > > > > And the clouds
> > > > > > > > > in the radiant skies are really stupid-looking hand-painted
> > > > > > > > > chicken scratches.  The regular "skies" package is not as bad, but
> > > > > > > > > I
> > > > > > > > > wouldn't say I'm particularly impressed by it, either. Anyway,
> > > > > > > > > just a heads-up about a lame product.  For interiors at least,
> > > > > > > > > just save yourself some money and make your own environment maps
> > > > > > > > > of your scenes... If you don't have a scene, just throw some cubes
> > > > > > > > > in there -- that's all Dosch did.
> > > > > > > >
> > > > > > > >
> > > > > > > > FWIW, I have gotten some models from Dosch that were more than
> > > > > > > > adequate for the price. So noth everything they have is lame. BUt,
> > > > > > > > like anything caveat emptor.
> > > > > > > >
> > > > > > > > --
> > > > > > > > Joe Laffey                |       Visual Effects for Film and Video
> > > > > > > > LAFFEY Computer Imaging   |
> > > > > > > > -------------------------------------
> > > > > > > > St. Louis, MO             |       Show Reel http://LAFFEY.tv/?e02809
> > > > > > > >  USA                       |
> > > > > > > > -------------------------------------
> > > > > > > > .                         |        -*- Digital Fusion Plugins -*-
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