[Bf-compositor] Clamping (Mix, Math, RGB Curves)

Francesco Paglia f.paglia.80 at gmail.com
Wed May 28 19:48:18 CEST 2014 

I tried this datapath too...
could you tell me which release of blender are you using?




2014-05-28 19:27 GMT+02:00 Diego Gangl <dnicolas at gmail.com>:

> It's working for me, but Blender gave me a different datapath:
> nodes["RGB"].outputs[0].default_value[0] .
> If I change it the 0 to RGBA I get an error too. I guess you can't use
> dictionaries for sockets in drivers?
>
> 2014-05-28 9:15 GMT-03:00 Francesco Paglia <f.paglia.80 at gmail.com>:
> > Hey Diego,
> > I successfully added the driver,
> > I got the problem in the path of the RGB..
> > Here the picture I made to explain the problem:
> >
> >
> https://lh6.googleusercontent.com/-k6GDiWl4uNU/U4XRy1AzQ_I/AAAAAAAAJy8/C-xuqUDrNKM/w1357-h784-no/value.jpg
> >
> > I forgot to open the panel in the left of the drivers ..
> >  I'm working on the red channel of the ramp and I was trying to evaluate
> the
> > red value of the RGB node that is perfectly showed in the python console
> but
> > as you can see return a red background on the path of the driver....
> >
> > Am I missing something?
> >
> >
> >
> >
> > 2014-05-28 13:15 GMT+02:00 Diego Gangl <dnicolas at gmail.com>:
> >
> >> Hey,
> >>
> >> Nice work on those nodegroups, I'd like to see them too. It would be
> >> great to have some kind of standard library of nodes for motion/video
> >> work in the compositor with stuff like this.
> >>
> >> Francesco,
> >> Have you tried the outliner workaround for problem #2? You'd have to
> >> find the node in the outliner, then the socket, select it and press D
> >> to add the driver. Btw, it doesn't change color in the ui sometimes.
> >>
> >> I tried the nodes addon but I get a missing paths error, maybe it
> >> hasn't been updated?
> >>
> >> Cheers,
> >>
> >> 2014-05-28 7:15 GMT-03:00 Francesco Paglia <f.paglia.80 at gmail.com>:
> >> > Hey Sean,
> >> > I'm really interested in seeing your node and much more on the match
> >> > color
> >> > node...
> >> > I've tried by myself making one but I couldn't find a nice way to have
> >> > the
> >> > setup embedded in a node group.
> >> >
> >> > Looking at the tutorial the artist simply match low and hi valuse of a
> >> > levels effects for each channel.
> >> > So I though I can mimic that result just with a simple setup:
> >> > 1. separate RGB  of the input,
> >> > 2. add a color ramp to each channel (to get a remap of Hi and LOW
> value)
> >> > 3. add a combine channel to recreate the final image
> >> >
> >> > The result looked promising but
> >> > 1. to expose the value of the ramp you have to add a driver on each
> stop
> >> > of
> >> > the ramp
> >> > 2. the driver (don't know why) in official 2.70 build seems cannot
> read
> >> > the
> >> > value of a node RGB.output or the input of the group even if it is
> >> > readable
> >> > in the python console (the driver simply show the path background in
> red
> >> > color)
> >> > 3. value are clamped in the 0-1 range so if values exceed this range
> >> > they
> >> > are remapped.. (well this is a known side effect driven by the node
> >> > used...)
> >> >
> >> > I'm curious to know your approach :)
> >> > Thanks,
> >> > Francesco
> >> >
> >> >
> >> > 2014-05-28 7:57 GMT+02:00 David McSween <3pointedit at gmail.com>:
> >> >
> >> >> I would certainly be interested in a 'colour matcher' node group.
> >> >> Especially if it Rock My World as Mark says in the link ;-)
> >> >>
> >> >> These look really useful, it would be great if everyone could at
> least
> >> >> match pedestal across their elements.
> >> >>
> >> >>
> >> >> On Wed, May 28, 2014 at 2:07 PM, Sean Kennedy <
> mack_dadd2 at hotmail.com>
> >> >> wrote:
> >> >>>
> >> >>> Hey guys,
> >> >>>
> >> >>> I made a few nodegroups we were discussing.
> >> >>>
> >> >>>
> >> >>>
> https://www.dropbox.com/s/uj9kw6dm1sp3cot/clamp_nodes_screenshot_02.jpg
> >> >>>
> >> >>> I made a Value clamp, as Deigo had made. Then I made a RGB clamp,
> >> >>> where
> >> >>> you can set R, G, and B individually. And then I made the node I
> >> >>> really
> >> >>> wanted, a black levels node.
> >> >>>
> >> >>> When you're compositing one image over another, and they come from
> two
> >> >>> different sources, they usually have completely different color
> values
> >> >>> in
> >> >>> the highs and lows (obviously, we all know this). At R&H, we had a
> >> >>> great
> >> >>> Black Levels node where we could simply sample a dark spot of a
> >> >>> background
> >> >>> plate, and the darks of the foreground plate would just shift to
> >> >>> match. This
> >> >>> works the same exact way. It was ideal for CG elements going over
> live
> >> >>> action plates, because usually the general highs and overall color
> of
> >> >>> the CG
> >> >>> matched the plate fine, but the blacks always came in as absolute
> >> >>> blacks, or
> >> >>> sometimes negative blacks. This node made fixing it a 1-click
> >> >>> operation.
> >> >>>
> >> >>> If anyone is interested, I can upload a blend file with the
> >> >>> nodegroups.
> >> >>> The clamps are super easy to make, though. But maybe the black
> levels
> >> >>> one
> >> >>> would be interesting to someone?
> >> >>>
> >> >>> Tomorrow I'm going make a node setup to easily replicate Mark
> >> >>> Christiansen's techniques for matching the general colors of one
> plate
> >> >>> to
> >> >>> another. You can see the technique here in the free sample videos,
> if
> >> >>> you're
> >> >>> interested.
> >> >>>
> >> >>>
> >> >>>
> http://www.lynda.com/After-Effects-tutorials/After-Effects-Compositing-Essentials-Matching-Foreground-Background/114913-2.html
> >> >>>
> >> >>> It's fun making these!
> >> >>>
> >> >>> Sean
> >> >>>
> >> >>> ________________________________
> >> >>> From: f.paglia.80 at gmail.com
> >> >>> Date: Sun, 25 May 2014 09:50:01 +0200
> >> >>> To: bf-compositor at blender.org
> >> >>> Subject: Re: [Bf-compositor] Clamping (Mix, Math, RGB Curves)
> >> >>>
> >> >>> Thanks for the advices Diego and David!
> >> >>> Just a little thought:
> >> >>> Adding lot of nodegroups in a single "category" - I mean in the same
> >> >>> menu
> >> >>> list - isn't that efficient... is there a way to manage their
> position
> >> >>> in
> >> >>> the SHIFT+A menu?
> >> >>>
> >> >>> Referenced node group are quite "risky" since compositing session
> >> >>> works
> >> >>> most likely WYSIWYG and as soon as you change something you have to
> >> >>> check
> >> >>> back each project... but I get your point Diego... I'm very used to
> >> >>> linked
> >> >>> group, they are so useful and I hope they will be empowered a lot
> with
> >> >>> gooseberry since Proxyfication have room for for lot of improvement.
> >> >>>
> >> >>>
> >> >>>
> >> >>>
> >> >>>
> >> >>>
> >> >>> 2014-05-25 4:26 GMT+02:00 David McSween <3pointedit at gmail.com>:
> >> >>>
> >> >>> Don't forget the addon Node Presets
> >> >>>
> >> >>>
> http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Compositing/Compositing_Presets
> >> >>> I think you can add node groups and store them in a portable file.
> >> >>>
> >> >>> On 25 May 2014 09:59, "Diego Gangl" <dnicolas at gmail.com> wrote:
> >> >>>
> >> >>> >> It is possible to clamp (blacks and whites individually even),
> but
> >> >>> >> whenever I want to do it I have to add gazillion nodes. It takes
> >> >>> >> time.
> >> >>> >> My
> >> >>> >> intention is to make it with a single click.
> >> >>>
> >> >>> You can turn them into a group, plug the math values into group
> >> >>> inputs, name it and bam! your own Clamp Node that you can add from
> the
> >> >>> group menu.
> >> >>>
> >> >>> > Isn't there a way to develop few nodegroup store them somewhere
> and
> >> >>> > recall
> >> >>> > them in a personal group list or add them in the lists we already
> >> >>> > have?
> >> >>>
> >> >>> There's two ways:
> >> >>>
> >> >>> 1- Make the groups in a new (empty) blend file, then save it as your
> >> >>> start-up file (ctrl+U). The node groups will be available in every
> new
> >> >>> file you make.
> >> >>>
> >> >>> 2- Make a "Node Library" file. Make all your groups there, then
> make a
> >> >>> new empty file and link all the groups from the library file. Save
> it
> >> >>> as your start-up file and you get all the groups. The cool thing is
> >> >>> that if you tweak the groups inside the lib file, they will be
> upated
> >> >>> in all the blend files that link them.
> >> >>>
> >> >>> Gooseberry is going to bring a lot of developement into asset
> >> >>> management, so it will get better.
> >> >>>
> >> >>>
> >> >>> 2014-05-24 7:00 GMT-03:00 Francesco Paglia <f.paglia.80 at gmail.com>:
> >> >>> > Isn't there a way to develop few nodegroup store them somewhere
> and
> >> >>> > recall
> >> >>> > them in a personal group list or add them in the lists we already
> >> >>> > have?
> >> >>> > Could it be a python add-on?
> >> >>> > This would help us skip the tedious part of reloading those node
> >> >>> > every
> >> >>> > time
> >> >>> > a new blend file is created and also could help us distribute
> those
> >> >>> > nodes in
> >> >>> > their coherent place.
> >> >>> >
> >> >>> >
> >> >>> >
> >> >>> > 2014-05-24 11:31 GMT+02:00 Bartek Skorupa (priv)
> >> >>> > <bartekskorupa at bartekskorupa.com>:
> >> >>> >
> >> >>> >> It is possible to clamp (blacks and whites individually even),
> but
> >> >>> >> whenever I want to do it I have to add gazillion nodes. It takes
> >> >>> >> time.
> >> >>> >> My
> >> >>> >> intention is to make it with a single click.
> >> >>> >> How much time did it take you to set up this fantastic node tree
> of
> >> >>> >> yours?
> >> >>> >> If it's more than one second - itś too much. It should be:
> Decision
> >> >>> >> =>
> >> >>> >> 1
> >> >>> >> second later: DONE.
> >> >>> >>
> >> >>> >>
> >> >>> >> Bartek Skorupa
> >> >>> >>
> >> >>> >> www.bartekskorupa.com
> >> >>> >>
> >> >>> >> On 24 maj 2014, at 00:10, Sean Kennedy <mack_dadd2 at hotmail.com>
> >> >>> >> wrote:
> >> >>> >>
> >> >>> >> Ah, great idea! We could even set one up with RGB, one on each
> >> >>> >> channel,
> >> >>> >> and save it as a nodegroup.
> >> >>> >> Thanks! So obvious, don't know why we didn't think of this. :)
> >> >>> >>
> >> >>> >> I'm going to set one up today.
> >> >>> >>
> >> >>> >> sean
> >> >>> >>
> >> >>> >> > From: dnicolas at gmail.com
> >> >>> >> > Date: Fri, 23 May 2014 19:07:28 -0300
> >> >>> >> > To: bf-compositor at blender.org
> >> >>> >> > Subject: Re: [Bf-compositor] Clamping (Mix, Math, RGB Curves)
> >> >>> >> >
> >> >>> >> > Hi all, I don't know how Blender's handles colors internally
> but
> >> >>> >> > wouldn't this work?
> >> >>> >> > http://www.pasteall.org/pic/show.php?id=71736
> >> >>> >> > (or are the V values already mapped to 0-1 from the separate
> >> >>> >> > node?)
> >> >>> >> >
> >> >>> >> > Cheers,
> >> >>> >> >
> >> >>> >> > 2014-05-23 18:46 GMT-03:00 Sean Kennedy <
> mack_dadd2 at hotmail.com>:
> >> >>> >> > > Could we set the value of the clamp? It could come in as
> >> >>> >> > > defaults
> >> >>> >> > > of
> >> >>> >> > > 1.0 and
> >> >>> >> > > 0.0, but we could alter it to whatever we wanted. At R&H,
> most
> >> >>> >> > > of
> >> >>> >> > > the
> >> >>> >> > > time
> >> >>> >> > > we clamped brights around 14-16. We'd only turn it down under
> >> >>> >> > > that
> >> >>> >> > > if
> >> >>> >> > > we got
> >> >>> >> > > bad pixels when rendering.
> >> >>> >> > >
> >> >>> >> > > If you had a superbright red, like R 12, G 3, B 4, and you
> put
> >> >>> >> > > a
> >> >>> >> > > clamp
> >> >>> >> > > of 1
> >> >>> >> > > on it, obviously it's going to set each value to 1, so what
> was
> >> >>> >> > > red
> >> >>> >> > > now
> >> >>> >> > > reads as white. But it would still be useful.
> >> >>> >> > >
> >> >>> >> > > After Effects clamp tool
> >> >>> >> >
> >> >>> >> > >
> >> >>> >> > > >
> >> >>> >> > > > > >
> http://cdn.aescripts.com/media/catalog/product/cache/1/image/800x600/040ec09b1e35df139433887a97daa66f/f/t/ft-clamp-ui_1.png
> >> >>> >> > >
> >> >>> >> > > Nuke clamp is in the color grade node
> >> >>> >> >
> >> >>> >> > >
> >> >>> >> > > >
> >> >>> >> > > > > >
> http://docs.thefoundry.co.uk/nuke/63/pythondevguide/_images/getMinMax_01.png
> >> >>> >> > >
> >> >>> >> > > I'm not posting the images to say "this is how we should do
> >> >>> >> > > it",
> >> >>> >> > > but
> >> >>> >> > > rather,
> >> >>> >> > > to say it is useful and professional compositors would indeed
> >> >>> >> > > use
> >> >>> >> > > it
> >> >>> >> > > often.
> >> >>> >> > >
> >> >>> >> > > In fact, I was working on a shot this week that could have
> used
> >> >>> >> > > it. I
> >> >>> >> > > was
> >> >>> >> > > given stock footage from a client, and I have no idea how
> much
> >> >>> >> > > they'll
> >> >>> >> > > color
> >> >>> >> > > correct it in post once I deliver the final vfx shot. SO I
> have
> >> >>> >> > > to
> >> >>> >> > > make sure
> >> >>> >> > > all my blacks are in line with what is in the plate. I put a
> >> >>> >> > > gamma
> >> >>> >> > > on
> >> >>> >> > > the
> >> >>> >> > > plate just to view the black levels and see how they match up
> >> >>> >> > > when
> >> >>> >> > > pushed
> >> >>> >> > > really far.
> >> >>> >> > >
> https://dl.dropboxusercontent.com/u/10553822/clamp_blacks_01.jpg
> >> >>> >> > >
> >> >>> >> > > Since we don't have a clamp, I ended up putting a mix node
> >> >>> >> > > right
> >> >>> >> > > after
> >> >>> >> > > the
> >> >>> >> > > stock footage node, setting it to Lighten, and making the
> color
> >> >>> >> > > over
> >> >>> >> > > it
> >> >>> >> > > black. then I slowly raised it while watching until the
> blacks
> >> >>> >> > > all
> >> >>> >> > > came in
> >> >>> >> > > line. Would have been much easier to sample the value of the
> >> >>> >> > > darkest
> >> >>> >> > > dark I
> >> >>> >> > > wanted in the shot, throw a clamp node on with the black
> clamp
> >> >>> >> > > set
> >> >>> >> > > to
> >> >>> >> > > those
> >> >>> >> > > values.
> >> >>> >> > >
> >> >>> >> > > In fact, at R&H, the Black Clamp node let you set an
> individual
> >> >>> >> > > value
> >> >>> >> > > for R,
> >> >>> >> > > G, and B. And it had a color picker so you could just sample
> >> >>> >> > > the
> >> >>> >> > > image
> >> >>> >> > > and
> >> >>> >> > > the values would fill in automatically.
> >> >>> >> > >
> >> >>> >> > > Anyway, just throwing out my $0.02. Obviously I've found a
> >> >>> >> > > workaround
> >> >>> >> > > and
> >> >>> >> > > can live with it, but it would sure be great to someday see a
> >> >>> >> > > clamp
> >> >>> >> > > node.
> >> >>> >> > >
> >> >>> >> > > ________________________________
> >> >>> >> > > Date: Fri, 23 May 2014 14:21:40 -0700
> >> >>> >> > >
> >> >>> >> > > From: troy.sobotka at gmail.com
> >> >>> >> > > To: bf-compositor at blender.org
> >> >>> >> > > Subject: Re: [Bf-compositor] Clamping (Mix, Math, RGB Curves)
> >> >>> >> > >
> >> >>> >> > >
> >> >>> >> > > On May 23, 2014 1:56 PM, "Bartek Skorupa (priv)"
> >> >>> >> > > <bartekskorupa at bartekskorupa.com> wrote:
> >> >>> >> > >
> >> >>> >> > >> When I say: "clamp blacks" I always mean: set every value
> >> >>> >> > >> below
> >> >>> >> > >> 0.0
> >> >>> >> > >> to
> >> >>> >> > >> 0.0.
> >> >>> >> > >> When I say: "clamp whites" I always mean: set every value
> >> >>> >> > >> above
> >> >>> >> > >> 1.0
> >> >>> >> > >> to
> >> >>> >> > >> 1.0.
> >> >>> >> > >> Every compositing artist will know what I mean.
> >> >>> >> > >
> >> >>> >> > > If we can generate a clamp / scale node, I am all for it.
> >> >>> >> > >
> >> >>> >> > > I am saying there is no concept of white in a scene referred
> >> >>> >> > > model,
> >> >>> >> > > and as
> >> >>> >> > > such, you have to be careful as to not write nodes that break
> >> >>> >> > > the
> >> >>> >> > > system.
> >> >>> >> > >
> >> >>> >> > > It is that simple. No white. No brighter than white. So
> sorry,
> >> >>> >> > > "Every
> >> >>> >> > > artist..." is actually "Every artist unfamiliar with HDR
> work."
> >> >>> >> > >
> >> >>> >> > > So a clamp node _must_ not make the erroneous assumption that
> >> >>> >> > > 1.0
> >> >>> >> > > means
> >> >>> >> > > anything special, and rather provide for an arbitrary value
> >> >>> >> > > range.
> >> >>> >> > >
> >> >>> >> > > If this all seems like speaking an alien language, it is
> >> >>> >> > > precisely
> >> >>> >> > > why
> >> >>> >> > > I
> >> >>> >> > > chimed in and said "Whoa."
> >> >>> >> > >
> >> >>> >> > > There are already nodes that are broken because of erroneous
> >> >>> >> > > assumptions. It
> >> >>> >> > > would be a shame to make more.
> >> >>> >> > >
> >> >>> >> > > With respect,
> >> >>> >> > > TJS
> >> >>> >> > >
> >> >>> >> > >
> >> >>> >> > > _______________________________________________ Bf-compositor
> >> >>> >> > > mailing
> >> >>> >> > > list
> >> >>> >> > > Bf-compositor at blender.org
> >> >>> >> > > http://lists.blender.org/mailman/listinfo/bf-compositor
> >> >>> >> > >
> >> >>> >> > > _______________________________________________
> >> >>> >> > > Bf-compositor mailing list
> >> >>> >> > > Bf-compositor at blender.org
> >> >>> >> > > http://lists.blender.org/mailman/listinfo/bf-compositor
> >> >>> >> > >
> >> >>> >> > _______________________________________________
> >> >>> >> > Bf-compositor mailing list
> >> >>> >> > Bf-compositor at blender.org
> >> >>> >> > http://lists.blender.org/mailman/listinfo/bf-compositor
> >> >>> >> _______________________________________________
> >> >>> >> Bf-compositor mailing list
> >> >>> >> Bf-compositor at blender.org
> >> >>> >> http://lists.blender.org/mailman/listinfo/bf-compositor
> >> >>> >>
> >> >>> >>
> >> >>> >>
> >> >>> >> _______________________________________________
> >> >>> >> Bf-compositor mailing list
> >> >>> >> Bf-compositor at blender.org
> >> >>> >> http://lists.blender.org/mailman/listinfo/bf-compositor
> >> >>> >>
> >> >>> >
> >> >>> >
> >> >>> >
> >> >>> > --
> >> >>> > Francesco Paglia
> >> >>> > Vfx and Production Supervisor
> >> >>> >
> >> >>> > mobile  +39 347.82.12.473
> >> >>> > e-mail   f.paglia.80 at gmail.com
> >> >>> >
> >> >>> >
> >> >>> > _______________________________________________
> >> >>> > Bf-compositor mailing list
> >> >>> > Bf-compositor at blender.org
> >> >>> > http://lists.blender.org/mailman/listinfo/bf-compositor
> >> >>> >
> >> >>> _______________________________________________
> >> >>> Bf-compositor mailing list
> >> >>> Bf-compositor at blender.org
> >> >>> http://lists.blender.org/mailman/listinfo/bf-compositor
> >> >>>
> >> >>>
> >> >>> _______________________________________________
> >> >>> Bf-compositor mailing list
> >> >>> Bf-compositor at blender.org
> >> >>> http://lists.blender.org/mailman/listinfo/bf-compositor
> >> >>>
> >> >>>
> >> >>>
> >> >>>
> >> >>> --
> >> >>> Francesco Paglia
> >> >>> Vfx and Production Supervisor
> >> >>>
> >> >>> mobile  +39 347.82.12.473
> >> >>> e-mail   f.paglia.80 at gmail.com
> >> >>>
> >> >>>
> >> >>> _______________________________________________ Bf-compositor
> mailing
> >> >>> list Bf-compositor at blender.org
> >> >>> http://lists.blender.org/mailman/listinfo/bf-compositor
> >> >>>
> >> >>> _______________________________________________
> >> >>> Bf-compositor mailing list
> >> >>> Bf-compositor at blender.org
> >> >>> http://lists.blender.org/mailman/listinfo/bf-compositor
> >> >>>
> >> >>
> >> >>
> >> >> _______________________________________________
> >> >> Bf-compositor mailing list
> >> >> Bf-compositor at blender.org
> >> >> http://lists.blender.org/mailman/listinfo/bf-compositor
> >> >>
> >> >
> >> >
> >> >
> >> > --
> >> > Francesco Paglia
> >> > Vfx and Production Supervisor
> >> >
> >> > mobile  +39 347.82.12.473
> >> > e-mail   f.paglia.80 at gmail.com
> >> >
> >> >
> >> > _______________________________________________
> >> > Bf-compositor mailing list
> >> > Bf-compositor at blender.org
> >> > http://lists.blender.org/mailman/listinfo/bf-compositor
> >> >
> >> _______________________________________________
> >> Bf-compositor mailing list
> >> Bf-compositor at blender.org
> >> http://lists.blender.org/mailman/listinfo/bf-compositor
> >
> >
> >
> >
> > --
> > Francesco Paglia
> > Vfx and Production Supervisor
> >
> > mobile  +39 347.82.12.473
> > e-mail   f.paglia.80 at gmail.com
> >
> >
> > _______________________________________________
> > Bf-compositor mailing list
> > Bf-compositor at blender.org
> > http://lists.blender.org/mailman/listinfo/bf-compositor
> >
> _______________________________________________
> Bf-compositor mailing list
> Bf-compositor at blender.org
> http://lists.blender.org/mailman/listinfo/bf-compositor
>



-- 
Francesco Paglia
Vfx and Production Supervisor

mobile  +39 347.82.12.473
e-mail   f.paglia.80 at gmail.com
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