has anybody ever successfully used sunlight & mesh emitt

superbob · Post by **superbob** » Thu Nov 16, 2006 6:53 am

I ask this because I can't get it for the life of me. I max out my Gain...nothing different. If I change my system scale, then it works...but now my camera is screwed up because it's so small.

Am I missing something here? In all the examples I've seen, I don't think I"ve seen any sunlight+mesh emitter systems.

Thanks!

Aaron

Phil · Post by **Phil** » Thu Nov 16, 2006 7:23 am

Hi,

I do not know about sunlight, but...
I am just doing some test with environment map and mesh emitters.
(after a lot of tests this works)

What light do you youse for mesh emitters, blackbody or rgb?
what are the gain you are using?
I read about millions to achieve some good results.

Please give us some more informations!
Where are the screenshots?, what are your parameters?

regards, Phil

Phil · Post by **Phil** » Thu Nov 16, 2006 7:45 am

Hi,

just another question?

If I change my system scale, then it works...but now my camera is screwed up because it's so small.

What are you using as software?

Blender problem?, something else?, exporter problems?
Unit problems?

Regards, Phil

superbob · Post by **superbob** » Thu Nov 16, 2006 8:09 am

Thanks for the reply...

I'm using Max2Indigo v.615 in 3D Studio MAX

I could give you settings, but the main problem I'm having is with the scale and the lighting interacting with that. I need to scale it up big time for anything to work. The mesh emitter is cranked up to the hightest it can be and even then it's just a dim yellow.

I can email you the model if you'd like it for testing. I will post a screen shot, but I can't get any constant reults yet....

Aaron

Aaron

crsrma · Post by **crsrma** » Thu Nov 16, 2006 8:21 am

I had the exact opposite problem - an emitting mesh blowing out the scene. I just cranked the levels of it's color way low & finally got the sunlight back.

I haven't investigated much beyond that yet, but it may have to do with camera white_balance & whatnot, possibly the sky_gain would help too.

May want to have a peek at the reference manual, it's pretty robust.

superbob · Post by **superbob** » Thu Nov 16, 2006 8:39 am

The above is a picture of the scene with no emitter in it. (Looks like I think it should) The scale is very very large...this house here is over 1000 feet deep.

*(EDIT)*

The above image is with the emitter...cranked all the way up in all aspects...still just a dim white.

I am going to work on the house to the correct scale now...but it totally jacks stuff up.

Aaron

superbob · Post by **superbob** » Thu Nov 16, 2006 9:13 am

Wait a minute....I have it working. Gosh Darnit all! Max2Indigo has a bug. It exports the Gain out at 10...not 1000000...I had to change it in the XML and it worked.

Aaron

afecelis · Post by **afecelis** » Thu Nov 16, 2006 9:14 am

mesh emitters+sunlight is the holy grail of render challenges in Indigo!

One light always affects and disables the exposure of the other

DaveC · Post by **DaveC** » Thu Nov 16, 2006 12:05 pm

This picture:

http://www.indigorenderer.com/joomla/in ... temId=2094

has a mesh emitter and sunlight. Just don't put the emitter up too high and your sun will be fine. I think you need to keep it below 50% of maximum emit.

DaveC · Post by **DaveC** » Thu Nov 16, 2006 12:12 pm

Just checked the old blend file and the emitter on the torch (flashlight) is set to 0.48. And it worked

DaveC · Post by **DaveC** » Thu Nov 16, 2006 12:43 pm

My mistake. Tried to do a new render and the emitters don't work in version 0.6 unless there's no sun. Dammit. Sorry.

superbob · Post by **superbob** » Thu Nov 16, 2006 12:54 pm

Well, at least we knew it worked at one point...is this considered a bug then, or is it known about?

Sorry...new to Indigo and I don't know what the developer/s do or don't know.

Aaron

crsrma · Post by **crsrma** » Thu Nov 16, 2006 2:48 pm

Hi again, I can pretty much confirm it's not working as in 0.5, atleast. I just tried with the latest BlenderDev exporter.

I dunno, maybe the exporters need updating..? I don't think there's an included test scene that covers this.

boweeb007 · Post by **boweeb007** » Fri Nov 17, 2006 12:51 am

I wouldn't really call it a bug - just something that's not properly explained (except in the forums).

Here's what Nick had to say on another post:

mzungu's question:

So is Indigo designed so that the <blackbody> spectrum type sort of "saps" the environment of competing lightsources? (for lack of a better way of saying it...) It was a very interesting effect, when I cranked the <gain> on it: all the other sources of light seemed to go dark/black. Not quite sure what this means.

nick's answer:

What's happening is that the (Reinhard) tonemapping automatically maps the image so that the whole image is 'exposed' correctly. (e.g. maps the brightest white to rgb(1,1,1)) So if you have one light in your scene, and you make it twice as bright, the render should look exactly the same. But if one light is much brighter than another light, that light will dominate, and the scene will be 'exposed' for that light.

If you want to see the effects of changing light intensities more directly, try using linear tonemapping, which doesn't do automatic exposure.

So it's not the fault of the exporter (except that it misleads you as to what the max gain is) or indigo. This problem is solved with proper knowledge of how tonemapping works. I've responded to several posts on this subject before. I brought this to radiance's attention, to add something about this in the tutorial or faq, but he's been VERY busy.

crsrma · Post by **crsrma** » Fri Nov 17, 2006 1:14 pm

That was all fine info on tonemapping, but how does that explain such a disparity between how 0.5 & 0.6 behaves? Was there a significant change in that period regarding tonemapping?

has anybody ever successfully used sunlight & mesh emitt

has anybody ever successfully used sunlight & mesh emitt

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