Blender Exporter for Indigo06 v. 63beta4

[Jananton]

Yeah, flightgear.
Apologies to any devs reading this, it's not *total* crap, it's just... really, really annoying.

Well, just did a little excursion to their website and the pictures sure look better than I remembered it. Maybe their engine has improved as much too...

really good not to be always serious!

By the way, do we have a rendering plane here
Could this be a future new competition to render something

Now where do I have that ol' blender file of a six cylinder star engine I did a year ago, I wonder how that would look in indigo...

Greetings from searching for a backup cd in Amsterdam,

Jan

[Jananton]

NP Ono! just create the Indigo Flight Sim forum!

Didn't you know that was my secret assignment when I started posting here on newyears eve...
Hence the sunglasses...

Greetings from looking for my star engine in Amsterdam,

Jan

PS can you imagine how someone looks, eager searching for updates and patches, and just finding all the info you wanna know but was afraid to ask about virtual flight....

[Jananton]

Well Gang,

After I've got the feeling I opened pandora's box and now can't close the lid, lets quote a living blues legend of our time and say: "Let's get down to bussines". I left out the word "babe" at the end, because that would give the wrong impression...

Was it yesterday or earlier I told you all I was running two test renders to see how zuegs code proposal for implementing Stefan-Boltzmann Law would work out. So here is the result:



Note, I combined the two, left is a 5000K meshlight, right the 3200K one. Apart from that all other settings are the same for both. Allthough your eyes would make you believe that the left one has a little more light intensity, I think that's desceptive and that in fact this result is good enough for an update.
One thing to note here though, the rendering time has been more then 12 hrs. I say this, since ihmo u3dreal's solution had less grain earlier in the rendering process. I'm not completely sure why to be honest, since I don't believe indigo reads the xml file more than once, so the more complex calculation shouldn't be an issue.

I'm open for suggestions, my thought is to make both options available in the exporter. As far as I can see that wouldn't be that difficult to do. On the other hand, making the exporter settings even more complex also has a downside...

Well, if that didn't bring you all back to terra firma I don't know what does...

Greetings from sleepy Amsterdam,

Jan

[afecelis]

whoa Jan! That comparative is indeed interesting! Yet I agree with you that the exporter's options shouldn't get too technical or most of us will get lost with so many nuts and bolts to tweak! But I guess a basic option to select the "Stefan-Boltzmann Law" thingie wouldn't hurt, hehehe. Yet I'm curious; Is that a rendering algorithm, or the way to get the image to converge? (Googling right now for Mr. Boltzmann). Was it already included in Indigo but needed to be triggered thru the options that the script outputs? (or better said, this option wasn't exported before in the regular script, yet Indigo supported it and could've taken it into account in the rendering process?).

Hope this questions won't disturb your beauty sleep! Nite nite Jan, happy dreams.

regards,
Alvaro
ps. I'm sure U3dreal is gonna love the screenshot; he's a complete light-lover.

[zuegs]

@Jananton
Very nice render! Yes the 3200K will seem a bit darker because some emitted frequencies are outside of the visible spectrum i think. But total emitted energie seems to be the same as the 5000K one.

@afecelis
"Stefan-Boltzmann Law" is nothing special - it was already in some older v0.6t exporters (http://mediawiki.blender.org/index.php/ ... o_exporter). It was just LOST in the v0.62 exporter and i tried to convince coders that it should go back in as it's a physical law.
What does it do: if you create two meshlights in the same scene with different blackbody temperature as 3200K and 5000K and you render both with same "gain" you will see that the 5000K will render 6 times brighter than the 3200K light! That's physicaly correct and follows the "S-Boltzmann Law". But this isn't very handy for us I think, so we compensate/correct this gain directly while exporting and we give the 5000K mesh a 6 times lower gain, so both will look as expected more or less same bright (as you just changed the temperature in blender).

[Jananton]

What does it do: if you create two meshlights in the same scene with different blackbody temperature as 3200K and 5000K and you render both with same "gain" you will see that the 5000K will render 6 times brighter than the 3200K light! That's physicaly correct and follows the "S-Boltzmann Law". But this isn't very handy for us I think, so we compensate/correct this gain directly while exporting and we give the 5000K mesh a 6 times lower gain, so both will look as expected more or less same bright (as you just changed the temperature in blender).

So to make it confusing, the old way u3dreal had it in the script should read as tooltip or choice: S.Boltzmann Law and the one I did the test with could be named something as Kelvin Compensated...

Was it already included in Indigo but needed to be triggered thru the options that the script outputs? (or better said, this option wasn't exported before in the regular script, yet Indigo supported it and could've taken it into account in the rendering process?).

No, it has in fact nothing to do with indigo, but with the value that gets exported into the <gain> tag of a <blackbody>. In fact it's just a differend mathematical formula to take variables in account, that are of influence on this <gain> value...

Greetings from overcast Amsterdam,

Jan

[Jananton]

Hello All,

Just a little update. Busy with implementing a choice menu for S.Boltzmann or Kelvin compression I found that the LFactor value to balance mesh- and other lightsources visible only in Linear mode, also works in Reinhard tonemapping. This of course means that button will be available in both modes in the next version, but if you want to try it with your current (63beta3) version, go to linear, set a LFactor value (approx.125, mesh emit 0.9), then switch back to reinhard mode and render....

I was a little bit under the impression that reinhard mode was a kind of auto exposure mode, so maybe this only just works in the example you all know so well by now. I certainly didn't change anything in that part of the code...

Greetings from surprised Amsterdam,

Jan

[afecelis]

hehehe, surprised indeed! You keep nothing but amazing me.

I also wanted to ask you a quick question. Yesterday I tried the "texture map" option in environment to use an exr image. Although it's working fine I made some tests with the default gain value at 1.0 and then I tried extreme value changes like 10, 20 or 50 and same way down to 0.1 yet the resulting render didn't change. Is it supposed to be this way? I thought the gain value would burn or undersample the intensity of the hdri image.

Also, though it's not a problem, I love the new "Loa" to load the exr from a specific location, yet on export the xml hard-writes the path to \HDR. So my question or suggestion would be; should we always place our exrs in a "HDR" folder where we got our .blend file (which I find to be an organized way), or could the "Load" option write the proper relative path to the exr image?

The old way was placing the exr at the same level of the .blend (and xml) so that by just typing the name of the exr image in the "Probe" field, Indigo would find it by default.

regards, from extremely hot and sunny Bucaramanga

[zuegs]

hi jananton

S.Boltzmann or Kelvin compression

I'm confused. What you mean now with "Compression" ?

I suggest to put a toggle button that's called "blackbody temperature compensation" or "BB compensation" (or "Kelvin compensation" if you like).
No one will understand what the "S.Boltzmann" stuff will do, it should just be noted in the code to remember where the formula was coming from (nothing for users ).

[afecelis]

hehehe, Zuegs is right. For someone like me it should even be something like a toggle button that says:
"pretty yellowish light"
and
"pretty white light"

[Jananton]

hi jananton

S.Boltzmann or Kelvin compression

I'm confused. What you mean now with "Compression" ?

I suggest to put a toggle button that's called "blackbody temperature compensation" or "BB compensation" (or "Kelvin compensation" if you like).

Well, I made it a menu with two choices, but a toggle button, why didn't I think of that... Ok Kelvin compensation it is then. I thought of compression analog to sound compression, the emitting values for different K values are compressed to stay within a certain emit range. Oh well, I don't mind, when all tinkering is done there should be some form of doc anyhow...

@afecelis - Hmm, now you've got me, that's a part of 62beta1 code I haven't looked at at all yet. Also I have to admit I've no idea what an exr image is or how to get one... I saw your little tutorial about this kind of files in another thread, but I'm at a loss yet where you can use it for. Is it something like the EnvMap texture option in blender.
On another note, can you verify the gain is supposed to work in indigo 0.6, the Skysun gain is disabled, could it be the same case here...

The above also goes for the HDR stuff you mention. It seems I'll have to do some study into this part, so please, please please, a little patience...

If you have a link to your tutorial here that would be handy, also links to other sources of documentation on these formats and use would be helpfull.

Greetings from overcast Amsterdam,

Jan

[afecelis]

arrrrrrggggghhhhhhhhhh! darn! I just lost like 4 paragraphs of info I had written here!!! lol!
I was explaining the hdri, exr thingie, though not in technicl terms, in an understandable way!!! Ouch! Now I'll have to make it the quickie way
Technical explanation of hdri:
http://en.wikipedia.org/wiki/HDRI
Technical explanation of exr:
http://en.wikipedia.org/wiki/OpenEXR
OpenEXR site:
http://www.openexr.com/

both (hdri and exr) are high dynamic range imaging formats which are special textures that grab the lighting info of a specific place including its local conditions. This textures are great for exterior renderings since everything gets tinted by the color of it, resulting in a more realistic image; hence, it's ideal for composite work and that's why it's a technique widely used in the film industry.

Blender supports both hdr and exr images when added as textures to the camera; but blender internal renderer doesn't read the lighting info (nor its spherical nature), but yafray does; check these 2 screenies:
blender internal:

same scene rendered with yafray:


so other renderers like Indigo, Kerkythea, Radium, etc also support hdri images in them.

Is it something like the EnvMap texture option in blender?

Yup, the concept is similar, but the texture is added to your "world" (camera).

On another note, can you verify the gain is supposed to work in indigo 0.6

Just checked with different values and the render didn't change either. MMMMh, I think I was changing them in the xml then.

If you have a link to your tutorial here that would be handy, also links to other sources of documentation on these formats and use would be helpfull.

Sure! the tut is here:
http://www.indigorenderer.com/joomla/fo ... php?t=1071
though my ftp provider's server is down, so no chance to check the screenies or DL the files, but give me some time and I'll mirror the whole stuff. As of links, check the ones pasted above

man! In the end this post, even after the info loss, didn't turn out that bad!

Regards,
Alvaro
ps. Check this screenie I just posted in the WIP section:
http://www.indigorenderer.com/joomla/fo ... php?t=1085
Should you be interested, I could send you the scene and exr images. Just shout!

[Jananton]

Hello afecelis,

Well, that was helpfull and educational indeed, thank for bringing this option to my attention. I could have been toying for weeks without noticing this little hidden gem...

I made some tests with the default gain value at 1.0 and then I tried extreme value changes like 10, 20 or 50 and same way down to 0.1 yet the resulting render didn't change. Is it supposed to be this way? I thought the gain value would burn or undersample the intensity of the hdri image.

Well I'm doing some tests now with my newly acquired knowledge and I can inform you gain defenitly does work. Only what you call extreme is probably peanuts. In one I did 110, found it a bit dark, pumped it up to 310 and that looks very good through the windows of my seaside cottage...
The only thing I can think of is you either use Reinhart tonemapping, or the exr file you use is very dark. Can one say that about such a file, hmm I don't know actually..

About that arbitrairy HDR folder, I had a look and that is hard coded in the script. I have to think about that one. Nicest would be to be able to set a path in the script that's persistant between sessions, so you could have a central point on your HD where al these files reside. Otherwise the chance of having multiple copies scattered everywhere eating up space is quite big. Due to the way indigo reads textures for objects one folder for texture files is not possible, but for these environment exr files it looks defenitly possible. As said, I have to think about this some more...

Greetings from enthousiast Amsterdam,

Jan

Btw, nice theapots, OpenGL or homebrewn.?

[afecelis]

hehehe, I'm, glad that bug has bitten you as well!

You're right! I'm using Reinhard all the time My triple bad!
Could you tell me which values you're using with linear so that I can reproduce them as well?

Btw, nice theapots, OpenGL or homebrewn.?

hehehe, naaaaaaaah!, neither; Scorpius' teapot cript :
http://chronosphere.home.comcast.net/sc ... teapot.zip
You weren´t expecting me to use 3dsmax just because of its teapot model, huh?

regards,
Alvaro

[afecelis]

quick note to let you know of 2 things Jan;
1. The hdri tut files have been mirrored so it's back online:
http://www.indigorenderer.com/joomla/fo ... =8849#8849
2. Here's a superb example of HDRI used in a composite; check how well 3d blends in with the ambiance of the surroundings (I had posted it in offtopic already):
http://www.jsmoral.com/media/mazingerz.jpg

greetings from robotic Bucaramanga, hehehehe