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bcd

Lumen values way off?

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Place a real 60w bulb in a real 1m box. It will floodlight it.

Place a VW 60w incandescent bulb in a 1m box - its effect is barely noticeable.

Place a VW 1000 Lumen point light in the box - its effect is barely noticeable.

Increase to 10,000 Lumens - now it's beginning to have an impact.

Why is this? Is VW consistently misreading Lumens by a factor of 10 or 20?

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Thanks Peter - done.

As a matter of interest here's the bulb in VW 12.5 -( it comes in with 900 Lumens).

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So what you are saying it that the new renderworks is fualty and that 12.5(my previous Ver.) was correct?

Similar to my other post where VW are releasing new versions when the older or current has not been fixed, now they make them fualy too

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Hello Carl:

Use the Emitter Brightness value in the Lighting Options dialog to increase the brightness of lights that use physical brightness values. Lightworks and Maxon differ by around 250% for how bright physical lights are shown, which is why the Emitter Brightness value for older files is set to that value when brought into 2011 or later.

Renderworks 2011 and later (and CINEMA 4D) show physical values at a lower brightness than Renderworks 2010 and earlier with the Lightworks render engine. New files use 100% (i.e. native CINEMA 4D values) which might be too low for cases like yours.

This happens because there is not an automatic one-size-fits-all conversion from lumens to monitor RGB brightness values. Physical light brightness values would have to be paired with a physical camera (as in C4D R13) for the light brightness versus pixel brightness conversion to be more intuitive. For now you have control with the Emitter Brightness value (and Image Exposure in the Custom RW Options too).

(Your light object should use Realistic distance falloff rather than None falloff if you want realistic looking lighting as well)

Edited by Dave Donley

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Here's the file with a 2500 Lumen point light source and

Realistic falloff.

The stock 60W bulb still produces the result attached above.

To my eye this is a glaring bug (ftp).

Can anyone produce an overly bright or even realistic illumination using 900 Lumens point light in VW 2011 or VW 2012 on any monitor?

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I agree; I also doubt that this is Mointor issue.

checked it in C4D directly,and get also all Black pixels

with a Fotometric Lightsource on 900 Lumens.

Not even a shadow in the darkness.

(Histogramm in Photoshop showing all Pixels on 0).

In the C4D Manual, I found something about setting the Lightsource to

Inverse quadratic (physically Correct), if there are real Bulbs involved.

Even then, I just get black Pixels.

A 60W Bulb/900 Lumen in 4m by 5m, 2.5m high Room should definitely show a serious Illumination, specially if there is term like "physically correct" involved in the Setting of the Lightsource, and I can type in Lumen or Candela Values, as Mathematically and Physically precise described Items.

To get some Light visible without increasing the Lumens to insane Values, I had to add a Gradient. (Screenshot attached). ??

Over all, I didn't get it down to clue, but it doesn't behave the way I would expect it.

Edited by Horst M.

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The virtual camera used by the C4D standard/RW renderer (not the physical camera) is calibrated to show bright pixels for a light that is much brighter than a 60W bulb. In RW you need to either make the light bulb brightness greater or instead (preferred) change the Emitter Brightness value to get this power of bulb to appear brighter. In C4D nowadays you would use the physical camera to have full control over how bright a 60W bulb appears, through exposure, film speed, etc.

There is no one-size-fits-all bulb brightness to pixel brightness conversion, please try the Emitter Brightness control to get this model to look brighter.

Edited by Dave Donley

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From the VW2012 Feature List:

"Physical lighting attributes allow you to define a light object with real-world photometric properties as well as by importing load distribution files provided by lighting manufacturers."

This doesn't hold.

I suspect this issue is much deeper than a mismatch between screen calibrations or even an inaccurate algorithm converting surface illumination to pixel brightness. Tweaking the brightness value or dimmer to achieve a look is more often than not a process reversal.

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Change the Emitter Brightness value in the Lighting Options dialog.

This does not require each light object to have its brightness or dimmer changed.

Edited by Dave Donley

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Thanks for your responses Dave,

Having bumped the emitter brightness by 250% the resulting brightness is still far from realistic.

As Horst mentions above, insane values are needed to begin to get anywhere close to a realistic result: all of which simply points to a bug. No?

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This is a very interesting discussion. I have often wondered what "Emitter Brightness" does. I would suggest that it is poorly labelled for what it does, since essentially it's a global multiplier.....

Kevin

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I have to say I tend to agree with you:

[img:left] 60wBulbs[/img]

Here's a custom point source on the left, specified to match the "electrically accurate lamp" on the left - and they do! Dimly.

and then there's:

[img:left] 24wFluo[/img]

which is an electrically accurate 24" fluorescent, which seem vastly more correctly brighter than the 60 bulb.

Edited by mjm

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And, one more for good measure:

[img:left] 50wHalogen Ref[/img]

this is a 50w Halogen reflector from the electrically accurate lamps folder - very bright!

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Vectorworks is really trying my patience. Today's fiasco: simple lighting. A fireplace that worked well in VW 2008, imported into 2013. When rendered, there's no light. So, I start from scratch (new file, new "light box" object, new bulb). Still, no light. Finally, after some time and frustration, I find that if I turn off "Use Emitter," there's light. But, of course, no way to control the light's color temperature. After trying everything I can think of, I finally find this thread and "intuitively" crank up the light's emitter brightness to a "realistic" 10,000 lumens. And, finally, voila, there's light!

There's lots of technical talk above and Dave Donley says "There is no one-size-fits-all bulb brightness to pixel brightness conversion...". Huh? I'm just a dumb designer. I want to put a light in my model, give it the 840 lumens that I think "lumens" means, and have light. Particularly where I was able to do so in VW 2008.

Maybe as discouraging as this regression in VW's lighting ability is the fact that this thread is over a year old, and this issue still hasn't been addressed, in spite of the fact that were using SP5 (SP3 if you count like an engineer) of VW 2013...

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This does not seem to be fixed in 2014 SP 3.

The best I can come up with is to set the Emitter Brightness (globally) to 1400. This more-or-less gives an emitter value of 1000 lumens = 100% brightness (after placing one light and then checking the HSB values of an emitter vs brightness).

Is there a chance it will be fixed at some point?

thanks

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Why are the brightness values still so far off in VW2016?

eg

1 candle = 4,000 Candelas??

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Hello bcd:

Can you include a VWX file?

In VW 2016 you can control the exposure using the RW camera effects, so you don't have to change the emitter brightness value anymore.

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In VW 2016 you can control the exposure using the RW camera effects, so you don't have to change the emitter brightness value anymore.

@Dave Donley - so are you saying that the Vw2016 RW camera now uses Cinema4D's Physical Camera and that using real shutter speed and exposure settings will accurately represent real-world photometrics? That would be great if it's true.

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Yes, 2016 uses the physical camera and physical renderer. Without the physical camera in previous releases you could only adjust the light and image brightness using the emitter brightness and image exposure options, since the virtual camera on the back end of the rendering had no parameters. Now with the physical camera (Add a RW Camera object, Activate the camera, and enable Camera Effects in Custom RW Options or RW Styles (Camera Effects are always on in Final Quality RW) ) this should be much more rational to control.

Try it out!

Use Custom RW to turn on Camera Effects, or use FQRW mode which has Camera Effects enabled always.

Edited by Dave Donley

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No camera.

Final Quality Renderworks on a Design Layer.

ubbthreads.php?ubb=download&Number=12966&filename=Candle%201850k%20100%.png

ubbthreads.php?ubb=download&Number=12968&filename=Candle%201850k%201000%.png

ubbthreads.php?ubb=download&Number=12969&filename=Candle%201850k%204000%.png

Edited by bcd

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Dave,

Do all sheet layer viewports rendered in Custom RW or FQRW use the physical camera settings (not just the user controlled ones) regardless of whether they are attached to a camera? It sounds like that's what you're saying.

I knew something had changed because the exposure values for a series of renderings had clearly shifted when I moved a project file from VW2015 to VW2016. I almost posted about it to see what was going on.

Kevin

Edited by Kevin McAllister

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No camera.

Final Quality Renderworks on a Design Layer.

That looks quite reasonable to me.

Or do I miss something ?

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You can still do it the old way without using a camera, but if you want to control the exposure in a better way then add a camera to the scene, make it active, turn Camera Effects on in Custom RW or use FQRW and you're on your way. HTH

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