Is the power parameter working for mesh lights?

[pciccone]

Hi.

I just did a test with LuxBlend to check the use of the power parameter. The first image shows a simple mesh light with the power set to 1W.

The second image is exactly the same scene but with power set at 100W.

They are slightly different but not to show a light 100 times brighter. The environment is set to "None". Am I missing something?

[SATtva]

I hope you're using Linear tonemapping?

[pciccone]

No, I'm using the default of Reinhard but I have nothing against Linear Thanks for the quick tip. We probably should document it. Maybe even a message in LuxBlend to let the user know that she has to use that tonemapping in order to have the power slider make any visible effect.

[Lord Crc]

This is documented, and the power slider will have and effect if you have more than one lightsource.

[pciccone]

I see. Well, the problem with the current status of the documentation is that it's a bit scattered. Don't mean it as a criticism, when you come from the outside of the development process you tend to look at few places for information. That something like this is documented in the FAQ but nowhere else makes it prone to this kind of posts. The usefulness of a reference doc is that it's the one place where everything should be found. The power and efficacy parameters are not documented in the File Format spec. nor is the fact that some light behavior changes with the tonemapper. The FAQ is a place to have it but there should be a more prominent way of seeing. Also, LuxBlend should detect the setting and advice the user about it.
Believe me, I have been reading the Lux documentation for the past few months every day. I do try to find the information without asking. As soon as I'm done with my current project I will restart updating the Lux documentation.

Thanks.

[Lord Crc]

Sorry if I sounded a bit harsh, was on my way out to dinner

I agree that the documentation situation is less than stellar, and I agree the FAQ could have better formatting and be more visible.

This kind of thing is what I've been wanting to have in a kind of "introduction to luxrender" article, because it is one of those things which is different from a lot of other renderers.

[pciccone]

Low sugar level making you cranky, eh? Happens to all of us

Here is an example of the issues that we have: http://www.luxrender.net/wiki/index.php ... ne_mapping

See that linear and reinhard are not explained.

I would suggest to actually avoid relying too much on the FAQ because that document tends to be read at first, when you are new to Lux, but then ignored later, especially if the first impression was that the FAQ was a bit shallow.
It's also a matter of terminology. While I understand that the underlying architecture has to be technically accurate, it's not always a good idea to expose it as it is to the end user. Tonemapping, for example, is a bit of a cryptic term.
I like to think of it as a "film development" process but I bet that a lot of people don't understand it, because of that ignore it, and because of that keep asking the same question.
Yes, a good introductory text that explains how to use Lux in easy terms would be definitely a great addition. The one in the Wiki is a good starti8ng point, it just needs to be completed and reviewed.

BTW, the mesh lights now work like a charm, really impressive stuff. I'll be posting images and news about some software that I'm writing around Lux soon. Just putting all the pieces together.

[binarycortex]

Here is an example of the issues that we have: http://www.luxrender.net/wiki/index.php ... ne_mapping

See that linear and reinhard are not explained.

I'll have to do something about that...

[pciccone]

I'll give my contribution to the docs soon. I'm currently swamped but in a few weeks I should be able to dedicate some time.

[binarycortex]

Linear is documented now. Working on Reinhard.