Hard question, how to determine the power of a light in poser ?

Knowing the sun is 100% infinite light,  how to determine a 25 watts light ?

There's no such thing unless you also establish the camera sensitivity.

If your camera is "set" for indoor, then the sun and other outdoor lighting should be 500 to 800%. Example here:

http://www.renderosity.com/mod/gallery/index.php?image_id=2324713&user_id=374541&np&np

At that point, the indoor lighting is 100%. See? It's whatever is just the right amount of light for your "exposure" to be good - which is around 100%.

earth's sun produces 3.846×10^26 W total, but little of that is visible, and only a tiny fraction is in light cone subtended by earth, hence do what bill said, otherwise it will be under- or over-exposed.  like using kodachrome at 1/100 second, f 1.4, in a room lit by a 25-W bulb.  it would be too dark to see much.

Ok without more camera options its just "au feeling", thx ;)

A watt is not a measure of light, a watt is measurement of power over time, defined as one joule per second. The watt has no direct correlation to luminosity. When you buy a 100 watt electric light, the wattage refers to the amount of electricity the light will use, not the amount of light it will produce.

In France bulb intensity are in watts in all markets, not logical but it's like that.

Anyway i have my answer ;)

A watt, relates to people who are hard of hearing...

In the States, lights are marked with the power consumption in Watts and the light output in Lumens.   A 25 Watt incandescent bulb puts out about 210 Lumens, whilst a 9 Watt compact flourescent lamp puts out 400 Lumens...

Quote - A watt, relates to people who are hard of hearing...

sorry could not resist. :)

tom, do you mean...

A: I'd like two bulbs of 40 watts

B: how many?

A: 40

B: 40... of what?

A: yes please

anyway, 100% light on a 100% surface makes 100% in the render. None of them has any physical meaning.

Lighting in a real room depends far more on the reflective surfaces than on the lumens of the bulb.  A 60-watt incandescent ceiling light gives enough light for ordinary living if the walls and ceilings are white ... but if the walls and ceilings are dark wood, the 60-watt bulb is useless.  Might as well have no lamp at all.

In the same realm of thought, does Poser 9 or 2012 support the use of IES profiles on light sources?  I know we have inverse square falloff for realistic decay, but the use of external IES profiles, especially on mesh lights, or material lights, helps tremendously to improve realism by duplicating not only decay by power, but also photometric web representation of different real-world light bulbs and fixtures.  For interior lighting, this plays a big role in arch/viz accuracy, and overall interaction with materials in the scene.  In other words, it "looks more real" than just a light cone with falloff and decay.

I was going to mention IES, which is the only place I know where the concept of something like a 60 watt bulb is relevant. I think that Carrara 8 supports IES lights. The only thing I have that does is Kerkythea and I've never messed with them. In ref to what Ockham said, I know that some manufacturers of things like textiles, paint or carpet provide bitmaps of their product textures. I don't know if  it would possible/desirable to have materials based on actual realworld surfaces, though obviously they'd be unique to a particular render engine - and for arch/viz that would probably be VRay, SketchUp etc.

Quote - I was going to mention IES, which is the only place I know where the concept of something like a 60 watt bulb is relevant. I think that Carrara 8 supports IES lights. The only thing I have that does is Kerkythea and I've never messed with them. In ref to what Ockham said, I know that some manufacturers of things like textiles, paint or carpet provide bitmaps of their product textures. I don't know if  it would possible/desirable to have materials based on actual realworld surfaces, though obviously they'd be unique to a particular render engine - and for arch/viz that would probably be VRay, SketchUp etc.

Well, not sure if it's possible, but certainly it's desireable to have the ability to reproduce realworld surfaces in Poser through native rendering.  I know it is possible to some degree, because Firefly allows you to specify IOR value for relfective/refractive surfaces, and has fresnel falloff for material parameters, which are realworld attributes.  So the same should apply for lighting.  Anything useful in Arch/Viz is as much useful in organic/Poser rendering too, if the end goal is realism.

Not to get off track, but I've used Vray for many years, and I produce mostly human-oriented/organic-centric renders.  At least that's my goal.  Now I'm using Luxrender on a network, simply because i feel the unbiased lighting is pretty much dummy-proof, and although the rendertimes have gone up substantially over Vray, the cost is offset by a much quicker prep time with regards to scene preparation and, specifically, lighting.  With Lux, for example, realistic reflective caustics just "happen", they aren't something you need to prepare the renderer for, or adjust parameters to achieve.  Same thing with realistic light bounce throughout the scene.  I can put a white panel in the scene, for example, and it will reflect light onto objects in the scene, as it should, exactly as I would expect it to in the real world, without making complex adjustments in the renderer for photon emission, or what have you.  It just works.

So something like IES profiles could only enhance our ability to achieve believable results without complex, or time consuming, workarounds.  What makes arch/viz renders look real, should, and do, make organic renders look real.  Etc. etc.

During the day in a "real" room, most of the light you see is indirect light.
What light do you see inside the room during a cloudy overcast?
Where is it? And where does it come from?
Where are the shadows, and where do they come from?

Attached Link: http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2807539&page=2#message_3679985

I lost that code by accident, and then didn't finish the work because I didn't feel like doing it over again. On the other hand, now that I have a store, maybe I should revisit this.

My question would be - do you really want IES, specifically, or just some cool designer lighting for Poser?

Quote -
My question would be - do you really want IES, specifically, or just some cool designer lighting for Poser?

I've been getting really frustrated with the limitations of Poser's lights recently - IES would be great, something I'd spend money on!

Does poser lighting work like this? I always got the feeling that it normalised around the strongest light source.

Quote - I lost that code by accident, and then didn't finish the work because I didn't feel like doing it over again. On the other hand, now that I have a store, maybe I should revisit this.

My question would be - do you really want IES, specifically, or just some cool designer lighting for Poser?

I missed the thread about this! It looks fantastic! I'd sure be interested in this BB. I downloaded the referenced zip file of IES and the viewer.

IES Would be handy I guess - there are truckloads of IES files on the interwebz

I feel like I may not have been clear. Do you really need IES lights or do you simply want 1000 or more interesting lighting distributions?

I can give you 1000 interesting lighting distributions as Poser presets, today, right now, this moment, without ever bothering with the IES data file format, and without you having to go download IES light profiles and run some Python script to convert them to Poser light shaders.

If I'm still not clear, what I'm saying is that having non-uniform light distribution has nothing whatsover to do with IES file formats. Do you need IES, or do you simply need interesting lighting?

speaking as someone who wants to use Poser with Sketchup to produce realistic architectual renders, yes. I do want IES implimentation. right now, I can make a real room, I can put in some figures, but I can't match real world lights with real world fittings. being able to do that would be very useful indeed.

Quote - I feel like I may not have been clear. Do you really need IES lights or do you simply want 1000 or more interesting lighting distributions?

I'd simply like more realistic lighting distributions, whether they be converted IES lights or BB's interpretations...

As an example of a non-IES light, but nevertheless one with an interesting pattern commonly found in real lights, have a look at this render.

Interesting effect !

Crikey, mate!  Is there no end to your talents?  They look amazing.

My (perhaps flawed) understanding is that with IES, you can have a room with a lamp and put a 'real' GE 100 Watt Soft White bulb in it or an array of Sylvania Grow Lites in your underground marijuana farm. Something else might yield equal or superior results. Obviously, if you're doing arch/viz then having the realworld reference is important since you can give clients a more realistic idea of what the space will look like with the specified lighting.

I suppose how important that is for Poser depends on how exacting someone is in terms of trying to recreate a real space. Some people who restore cars want exactly the carb that matches the build date of yada yada because they changed in the middle of the production run... Most folks probably aren't that picky about the lights I'd imagine as long as they look good. Perhaps for photographers or other people experienced with lighting having digital versions of the setups they're familiar with would be very desirable - assuming of course that they would actually get the expected results.

Quote - MG - doesn't Sketchup already support IES lights?

As an example of a non-IES light, but nevertheless one with an interesting pattern commonly found in real lights, have a look at this render.

only with other renderers, (Indigo, Kerkythea etc). but the point is, SU can't handle poser figures, (to high poly), so you have to bring SU mesh into Poser and render there.

Now I have to rewrite the IES file parser/interpreter.

The render shows 3 copies of the same light, but the back wall is turned so the distance to the light is different for each. It shows how complex this lighting can appear.

The splotches on the ground are IDL sample artifacts - I was using really cheesy settings for quick results.

Haaaaa-  that are lights....

I thought you where showing transonic boom waves inside a windtunnel... :-)

You could use that for a burning rocket motor also.

Or for transonic waves.

Or for bow waves.

Cool effects.
Nice job sir.

This is very cool indeed :-)

Quote - Good news - I have successfully rebuilt the light shader that can process IES-style sample information, at least for the axially symmetric forms.

Now I have to rewrite the IES file parser/interpreter.

The render shows 3 copies of the same light, but the back wall is turned so the distance to the light is different for each. It shows how complex this lighting can appear.

The splotches on the ground are IDL sample artifacts - I was using really cheesy settings for quick results.

Yep.  That would do the trick.

I just got P2012 the other day, and have been pretty impressed with the results I can get through Firefly these days.  Will save me time not having to export every scene to 3dsmax or Luxrender, or whatever, just for rendering with realistic light.

Quote - Do you need IES, or do you simply need interesting lighting?

BB, I would certainly like the IES capability, but if it makes more (commercial or logistical) sense to provide a load of 'interesting' lights, I'd be pretty happy with that.

Quote - > Quote - Do you need IES, or do you simply need interesting lighting?

BB, I would certainly like the IES capability, but if it makes more (commercial or logistical) sense to provide a load of 'interesting' lights, I'd be pretty happy with that.

Likewise... certainly the actual IES route sounds worthwhile and useful. But also simply having an up to date collection of realistically interesting Poser lights would also be great, for me.

In terms of IES light files... are there good sources of IES file format lighting setups, for download... ideally free download... online?

cheers ;-)

On the left, my Poser version of an actual IES light. On the right, the same light in the IES viewer.

The IES viewer presents the light against an invisible (and ambiguous) wall and an unspecified camera focal length. As I cannot determine the exact configuration of wall, light, and camera, I am unable to exactly match the light pattern. Also, I think the IES viewer is not dealing with gamma, and is darker than it should be.

So - I do not yet have exact visual confirmation that I'm doing it right, but everything is directionally correct. Every light I try produces the right features.

Good news :D

Getting deeper into this, I do not know how to interpret "physically accurate" in these circumstances.

Suppose a light profile has the following axial measurements from 0 to 60 degrees:

1 0 1 0 1 0

It is not at all clear how this light really looked - we just know that every ten degrees from center, the amplitude flipped from max to min.

Both of these interpretations obey the IES lighting profile 1 0 1 0 1 0

Again - these all are "accurate" - the word has lost all meaning to me now.

why not use a Renderer like Kerkythea that supports IES to make comparision render shots to see how your work is progressing?

I fear, this is one of those things where everybody is mathematically correct but all results are different.

To "diffuse light through air", you need; Correct : you need air.

Air, and its pollution, moisture, pressure, density, do not exist in the digital world.

A digital world is a vacuum. = No air, no pollution.

THE thing missing in the digital artificial world is :"The air we all breath".

Well, there's the atmosphere node: slow as hell to render (why? - it seems mathematically simple) but it'd be interesting to see some of these with atmosphere enabled.

But - it illustrates some problems with Poser's "simple" view of the world. First, the atmosphere is not obeying inverse square law - the smoke should be much brighter near the light sources. Second, IDL does not contribute to atmosphere, so there are many areas where we see IDL (bounced) light but do not see any smoke.

Oh well.