[SOLVED]mesh emitters disable sunlight?

afecelis · Post by **afecelis** » Sun Sep 10, 2006 4:15 am

Hi guys,

After Radiance's great tutorial I decided to try the basic stuff in a blender scene, however, the tutorial mentions you can have a sun light for exterior/general scene ilumination and combine it with mesh emitters for interior lighting but whenever I use both only the emitter prevails; I don't get light from the exterior nor a sky background.
some shots:
sun light only:

same sun light with interior emitter: (sun light gets disabled)

blender file:
http://afecelis.gdlib.net/Indigo/interior.blend

I'm using official verison 5 (as suggested in the tut) with the latest script available for it.

Any ideas?

spazz · Post by **spazz** » Sun Sep 10, 2006 4:23 am

I think you need to change the "Env Type" from "Map" to "SunSky" again in the Export-plugin's buttons.

afecelis · Post by **afecelis** » Sun Sep 10, 2006 4:31 am

Env type option is only available in version 0.6 script

There must be a way to achieve it in version 0.5 official....mmmhhhh mmmhhhh

leope · Post by **leope** » Sun Sep 10, 2006 4:48 am

Try to check if the xml statement for the sun/sky is present in the xml file.
If the statement is present then try to adjust the Sky Gain parameter of the exporter gui. Maybe is a sort of exposure adjust.

afecelis · Post by **afecelis** » Sun Sep 10, 2006 4:56 am

thanks Leope. Just checked the xml file and the skylight info is there and it's exactly the same as the one without the mesh emitter (I mean, it doesn't get disabled nor changed):

Code: Select all

<skylight>
		<sundir>-0.523896 -0.723479 0.449568</sundir>
		<turbidity>2.000000</turbidity>
		<sky_gain>0.005000</sky_gain>
	</skylight>

But if a mesh emitter is present skylight gest disabled as in my pic.
But Radiance mentions it very clearly:

Indigo does not support the standard blender light types (only the sun lamp)
Instead, use mesh emitters (see below) to create light sources.
For example, you can create an interior scene, have a skylight shining
trough the windows, and have additional lamps modeled as mesh_emitters.

Which is a similar setup as the scene I got, and he achieved it with version 0.5 so there must be some way.
Thanks for the help!

leope · Post by **leope** » Sun Sep 10, 2006 5:14 am

If i remember i had to raise the sky gain (a lot ?) to see the sky with an emissive mesh, in the external scenes too. Or try to decrease the power of the mesh light.
Meshlight are not mutually exclusive with the sun/sky and also hdr env, sun/sky and background are not mutually exclusive in 0.5, if i good remember, in 0.6 hdr env, sun/sky and background are mutually exclusive.

afecelis · Post by **afecelis** » Sun Sep 10, 2006 5:21 am

does Indigo code use specific pentium processor instructions/optimizations (like ss3)? I'm a deep AMD processor fan but got no 64 bits processor yet (the ones that started supporting SS3). I got a 3200 athlon XP that only gets to SS2. But I think you shouldn't leave us out of the posibility of using Indigo (if the optimization instructions is the case).

I just checked the same scene with 0.6 and used "sunsly" as env type and got the same black background if a mesh emitter is present. Also if I uncheck "bidirectional" tracing I get the following error when trying to render:

Dunno, I think I'll just give up. I've tried my best with this renderer but it doesn't seem to like me, heheheh. Version 0.5 is a bit more user-friendly but anyway. It was very educational.

thanks. Hope next official verison gets this minorities fixed.
EDITED Leope, I hadn't seen your post, you posted as I was writing this. I'll check lowering the emitter value or increasing the sunsky value. But this is my last attempt before i throw the towel.

afecelis · Post by **afecelis** » Sun Sep 10, 2006 5:38 am

aaaaaaaaaaaaaaaaaaaaaaaahhhhhhhhhhh!
Leope you nailed it down!

a material emitt value higher than 0.5 starts to make the skylight turn darker and darker. Values over 0.6 turn it to almost black!

Thanks a lot! Getting my towel back on my shoulder and moving on!
ps. Leope, I was chcking your missing floor thread. Nice scene. Also learned a couple of things from there. Thanks a lot.

Any other suggestions on mesh emitters are welcome (any gurus that would like to share their infinite wisdom, eheheheh).

regards,
Alvaro

boweeb007 · Post by **boweeb007** » Sun Sep 10, 2006 6:40 am

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.

That's why turning your emitter down helped - it's value was way out of proportion to your sky.

afecelis · Post by **afecelis** » Sun Sep 10, 2006 9:47 am

thnx boweeb007.

After reading a bit more about Indigo's technicalities your explanation comes in pretty handy.

I understand that indigo tries to mimmick real life ilumination at its best, hence how sensible it is to changes that may seem minor. But it also shows how demmanding it is for a good lighting setup.

Your tone map suggestion is worth a try. Thanks for that valuable info.

try using linear tonemapping, which doesn't do automatic exposure

How do you set it in 0.5?

afecelis · Post by **afecelis** » Sun Sep 10, 2006 10:14 am

But if one light is much brighter than another light, that light will dominate, and the scene will be 'exposed' for that light.

Which sometimes can work against one's intention. For instance, now the sunlight coming in thru the window (which was a hard shadow line) is barely noticeable.

I hope manual tonemapping can again enhance this effect

afecelis · Post by **afecelis** » Sun Sep 10, 2006 1:23 pm

radiance wrote:-> switch to linear tonemapping

greetz,
radiance

but there's no such option in 0.5 exporter. I did find this in the xml code:

Code: Select all

<tonemapping>
		<!--
		<linear>
			<scale>1.0</scale>
		</linear>
		-->
		<reinhard>
			<pre_scale>2</pre_scale>
			<post_scale>1</post_scale>
		</reinhard>
	</tonemapping>

Anything to modify there?

Thanks for the help Radiance!

afecelis · Post by **afecelis** » Sun Sep 10, 2006 1:41 pm

cool! like /* */ in c++ Thanks! Getting the hang of it!

Trying it out now.

afecelis · Post by **afecelis** » Sun Sep 10, 2006 2:19 pm

you might have to up it considerably

well I went trying different values from 1.0 to 250.0 and was still getting a black image. How hight must the value be?

afecelis · Post by **afecelis** » Sun Sep 10, 2006 2:46 pm

hehehe, that's quite higher than I expected

Radiance, is there a way of simulating a specific time of the day lighting? Or is it always that default blueish-orange horizon type? And does changing it's intensity from 1.0 in blender affect the renderer's lighting?

Trying new values now. Thanks a ton!
regards,
Alvaro