[Bf-cycles] Normalized Emission shader

Marco G marco.gzt at gmail.com
Thu Nov 13 17:27:40 CET 2014


I don't get entirely what's Sergey is suggesting.

@Germano - Seems overly complex compared to checking-unchecking a flag or
compared to a separated node.



2014-11-13 16:52 GMT+01:00 germano.costa <germano.costa at ig.com.br>:

> A solution for me would just put the option "Vector Scale" in the
> attributes of the object node. The control would be done only with the
> multiplication in math node.
>
>
> Enviado por Samsung Mobile
>
>
>
> -------- Original message --------
> From: Sergey Sharybin <sergey.vfx at gmail.com>
> Date: 13/11/2014 11:24 (GMT-03:00)
> To: bf-cycles at blender.org
> Subject: Re: [Bf-cycles] Normalized Emission shader
>
>
> The thing here is, both of new node type and option wouldn't make much
> sense if the shader tree is used by lamp. What is more tricky, the same
> shader tree could be hared between lamps and meshes.
>
> That makes making an UI which wouldn't be confusing a bit hard.
>
> Brecht, don't really think question which node to use is so huge an issue?
> Just give a clean name and artists will figure out which node they need i
> guess.
>
> On Thu, Nov 13, 2014 at 3:02 PM, David Black <db4tech at yahoo.co.uk> wrote:
>
>>  Hi Brecht,
>>
>> Great to have your input.
>>
>> In relation to lamp and emission plane calculation differences, can a
>> light type be identified internally from its lamp ID / emission plane? If
>> yes, would a more artist friendly solution be, instead of extra nodes, add
>> a Normalize check box to the Emission node with a helpful tool-tip,
>> something like...
>> "Light output remains constant while light source size changes"
>>
>> Hope things are going well for you.
>>
>> David
>>
>> 3d-designs-davidblack.blogspot.com
>> <http://www.3d-designs-davidblack.blogspot.com>
>>  On 12/11/2014 18:52, Brecht Van Lommel wrote:
>>
>> There's no significant performance hit, the surface area of the mesh
>> is already computed and stored for all objects so it's just a matter
>> of dividing by that.
>>
>> The main reason I didn't expose this option initially is because it
>> raises a bunch of UI questions as you guys found. There's a single
>> emission node for both meshes and lamps, so if they have different
>> defaults depending if they're added to material or lamp nodes, that's
>> a bit of an odd case not supported by the node system.
>>
>> Also related to this is how to show strength units for the emission
>> nodes, it's Watts for lamps normalized by surface area and Watts/m^2
>> for meshes without normalization. And there's the confusion around
>> "shadeless materials", which really are just emission nodes with
>> strength 1 but people keep asking how to do them, so perhaps there's a
>> way to improve the UI here.
>>
>> Perhaps separate nodes for normalized and non-normalized emission
>> could simplify things, and make it possible to show the right units,
>> but then people might get confused about which node to use, so it's
>> not ideal either.
>>
>> Brecht.
>>
>> On Wed, Nov 12, 2014 at 4:05 PM, Greg Zaal <gregzzmail at gmail.com> <gregzzmail at gmail.com> wrote:
>>
>>  Hey,
>>
>> I agree this could be useful. I'm guessing it'll work by checking the total
>> surface area which emits light and calculate the intensity based on that
>> maybe? Would there be any significant performance hit when (and when not)
>> using this feature?
>>
>> Personally I would prefer if this were not the default behavior, but we can
>> have that argument when/if it's implemented.
>>
>> Similarly, it might be useful to have the opposite behavior for regular
>> lamps - increasing the intensity as the size increases.
>>
>> Cheers,
>> Greg
>>
>> On 12 November 2014 16:27, Marco G <marco.gzt at gmail.com> <marco.gzt at gmail.com> wrote:
>>
>>  Hi, i'm happy other people thinks it's useful. Thomas said it could
>> implement it *eventually*, IF there is enough interest.
>> @Marc Dion, actually it's geared more towards another use case, mostly
>> flat mesh lights out of camera frustum to light subjects, withtout the need
>> to touch anymore its strength and instead focus on size/position etc to get
>> desired result...
>>
>> Hope to hear from other Cycles module member Greg and Matthew too. It's
>> one of those optional little features which improve daily work a lot.
>>
>> MG
>>
>> 2014-11-09 21:03 GMT+01:00 David Black <db4tech at yahoo.co.uk> <db4tech at yahoo.co.uk>:
>>
>>  Hi Marco,
>>
>> This is something I feel would be very helpful as the default behaviour.
>>
>> While improving Sweet Home 3D's render engine results (user db4tech),
>> lights is one of the areas I looked at, allowing size (for soft shadows) and
>> intensity changes, previously lights had a small fixed size and intensity.
>> One of my goals, to make it easier for artists, was to try and make sure
>> lights intensity remained constant while size was adjusted. Certainly made
>> light manipulation a lot easier and received very positive feedback.
>>
>> Link: (render results image links are no longer working)http://www.sweethome3d.com/support/forum/viewthread_thread,1688_offset,0
>>
>> David
>> 3d-designs-davidblack.blogspot.com
>>
>> On 09/11/2014 17:41, Marco G wrote:
>>
>> Hi members,
>>
>> months ago a feature regarding the Emission node has been removed, the
>> problem is that it was never exposed to the UI but actually pretty useful,
>> so i'm writing to ask to bring it back if possible and if other members
>> agree.
>>
>> With this option enabled the total amount of emitted light is the same
>> regardless of the mesh size. (it would still be optional of course).
>> Biggest advantage it would be that once you're satisfied with how much
>> light you have in your scene you can resize the light without affecting its
>> power, for example to make it bigger to soften shadows or get bigger
>> reflections, without the need to adjust the strenght since it would stay
>> equal
>>
>> If reimplemented, maybe a flag "Normalize" exposed in the emission node
>> would do the job?
>> Tooltip: "If checked, the total amount of emitted light is the same
>> regardless of the mesh size"
>>
>> Opinions?
>>
>> Thanks,
>> MG
>>
>>
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>
>
> --
> With best regards, Sergey Sharybin
>
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