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Area Light Help
Posted: 24 December 2012 10:25 AM   [ Ignore ]
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I am in the middle of doing a tutorial on Area lighting and I was always led to believe Ambient must be turned On for the light to emit. Well in DS3A 3.1.2.32 and DS4.5.1.6 this is not the case. I have tested all the presets and Base on various meshs, added other ligths etc and in every case with Ambient Turned OFF I get light.

So for you Daz Studio stalwarts out there can you, if you have time, check to see if this is the case and if so do you know when this changed?

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Posted: 24 December 2012 11:40 AM   [ Ignore ]   [ # 1 ]
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LOL! I thought it was always like that.

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Posted: 24 December 2012 11:54 AM   [ Ignore ]   [ # 2 ]
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This is it though Frank in early DS3 I have always had to turn ON ambient even with 0% intensity and people have confirmed this on many ocassions since. So since then I have always turned it on so I wouldn’t notice the difference with that practice. Only when I forgot to Turn On ambient I noticed this so hence me asking for confirmation in case I was going mad….... or getting more some would say. wink

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Posted: 24 December 2012 12:03 PM   [ Ignore ]   [ # 3 ]
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I’m not sure what you mean by emit? Ambiance is a surface property which makes a surface project it’s diffuse channel overriding and/or adding to the reflected light (or more properly lack thereof.) Not trying to tell you something you probably already know, just trying to clarify since I’m not quite sure what you are asking.

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Posted: 24 December 2012 12:11 PM   [ Ignore ]   [ # 4 ]
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Area lights can emit, project light from a given surface that has had the Area base added or an Area Light mesh preset, Plane, Disc, Tube etc. This is called Mesh Lighting as Lux and many other programs have, Daz Studio calls them Area Lights.

You can use just the Ambient channel of a Daz Default Surface as a light source when using UberEnviroment GI Preset, see the latest New Users contest for details on that http://www.daz3d.com/forums/viewthread/12654/P60/#197187

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Posted: 24 December 2012 12:14 PM   [ Ignore ]   [ # 5 ]
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Ok, I haven’t worked with area lights in a bit… I didn’t remember using the ambient channel to define the light emission for them.. that’s where my confusion was. I thought area lights had a separate property for defining light emission, but it’s been a while. Thanks for the link, I’ll read through it when I can focus on it. This is an area I need to play more in smile

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Posted: 24 December 2012 12:21 PM   [ Ignore ]   [ # 6 ]
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I can swear down that nearly everyone talking abut Area Light said that for it to work, as in provide light, the Ambient channel of the Area light surface needed to be turned on. That is all I wanted confirming by the long term users of daz Studio as I found this not to be the case now. Plus I can put my hand on my heart and say a few years back Area lights wouldn’t work until Ambient was turn on…even if you left the Ambient Intensity at 0% as long it was turn On that was enough for light..OFF meant no Light. This is why I got in to the habit of turning On ambient every-time I use Area Lighting…and hence not realising things have changed.

So if it is true now I need to amend my tutorial to suit the current set up. With Frank’s reply I will take it that this indeed is true. smile

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Posted: 24 December 2012 01:04 PM   [ Ignore ]   [ # 7 ]
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Gotcha, ty for putting together the tutorial smile

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Posted: 24 December 2012 08:33 PM   [ Ignore ]   [ # 8 ]
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Hi Szark

You may be thinking of the bad old days when over-driving the ambient was the only way to fake area lighting.

GI plus any standard material will do it. It doesn’t even have to be an ubersurface!

In the new area lights (DS4.5), the diffuse, ambient and opacity channels are still there but they really should not be.

...and setting a bright ambient can actually alter the intensity you’ve set, you’ll get an unexpectedly bright light unless you’re watching out for it. I’d recommend turning those channels off completely.

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Posted: 25 December 2012 04:10 AM   [ Ignore ]   [ # 9 ]
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Hi Szark

I have been messing around with area lights recently but after all that’s been said I didn’t think I’d have anything useful to add but after some consideration (and some quick testing) I think I might have especially after what prixat just said.

Now I’ve only been using Studio since February this year so I’m by no means an expert so I have no what the area lights were meant to do I just know what I want them to do…(I also don’t know how stuff worked in the good (or bad) ole days raspberry as I’ve only ever used 4 and 4.5)

First off: yes area lights do emit light when ambient is off or set at 0% however the area light does not light itself so if there are no other lights in the scene, without ambient, you’ll have a black-hole emitting light. This might be useful in certain scenarios but in some (a lot?) of cases this is not what you’re after. In those cases stetting the ambient will give your light a source.

As an example I’ll re-post an (newer version) of an image I posted earlier in an other thread here. I used two area lights there as well as an uberpoint light I might have gotten a similar effect using an other point light and a spot but I do remember messing with a spot and not being satisfied with the result. (Not sure why thought)

In the image the flash light on the shelve initially had ambient turned off (I turned it on but forgot to turn it up raspberry) and the light seemed to come from nowhere so I set it a 100. Now the effect is not as convincing as it should have been but I’ll have to do. I might add a “ting!” to it in post although I believe those things are frowned upon by real artists or maybe I’ll get better results by slightly lowering the ambient…

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Posted: 25 December 2012 05:01 AM   [ Ignore ]   [ # 10 ]
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prixat - 24 December 2012 08:33 PM

Hi Szark

You may be thinking of the bad old days when over-driving the ambient was the only way to fake area lighting.

GI plus any standard material will do it. It doesn’t even have to be an ubersurface!

In the new area lights (DS4.5), the diffuse, ambient and opacity channels are still there but they really should not be.

...and setting a bright ambient can actually alter the intensity you’ve set, you’ll get an unexpectedly bright light unless you’re watching out for it. I’d recommend turning those channels off completely.

Thanks for the reply but no I am not confused..well not about this one at least. smile

GI and ambient surfaces, yeah I know as the link above shows. smile

I don’t know what you mean by “In the new area lights (DS4.5), the diffuse, ambient and opacity channels are still there but they really should not be”.

Increasing Ambient surfaces on a Default surface will only make a scene brighter when you use Global Illumination…I have never come across a situation where that varies.

But we are getting away from the original question which has been answered now so thank you everyone for your input and help. smile

Now to get this tut finished and posted.

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Posted: 25 December 2012 05:05 AM   [ Ignore ]   [ # 11 ]
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Machieltje thank you for the confirmation, much appreciated…all the rest is not new to me but I thank you just the same for taking the time to post.

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Posted: 25 December 2012 08:22 AM   [ Ignore ]   [ # 12 ]
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Machieltje - 25 December 2012 04:10 AM

First off: yes area lights do emit light when ambient is off or set at 0% however the area light does not light itself so if there are no other lights in the scene, without ambient, you’ll have a black-hole emitting light. This might be useful in certain scenarios but in some (a lot?) of cases this is not what you’re after.

That is also how I always understood it, namely that the “Ambient” channel of the surface shader does not influence the emission of the light shader, but that you usually want to use both, in order to make the surface look like a light source, as well as behave like one.

And may I say, that’s a lovely illustration, Machieltje. smile

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Posted: 27 December 2012 03:49 AM   [ Ignore ]   [ # 13 ]
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JustTheBast - 25 December 2012 08:22 AM

...the “Ambient” channel of the surface shader does not influence the emission of the light shader…

Thats what I assumed at first.
to get the square arealight to show up on the spheres with this setup:

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Posted: 27 December 2012 03:54 AM   [ Ignore ]   [ # 14 ]
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I turned up the ambient from 0 to 100, leaving the intensity at 100.
...and got an image with 200% and some burnt out highlights:

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Posted: 27 December 2012 04:14 AM   [ Ignore ]   [ # 15 ]
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a couple of ways round it, I reduced the intensity to 0 and just relied on ambient.
(or you could reduce the overall exposure, that’s labeled ‘Gain’ in the render settings)

So for now ‘Ambient’ gets a reprieve LOL

If anyone has a use for diffuse or opacity in an arealight I’d like to see it. grin

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