TG2 GI Examples Page

[inkydigit]

I echo Frank et al....cheers!

[PorcupineFloyd]

Great reading, thanks for your work dandelO :-)

I'm sure it will be very helpful for everybody to understand how lightning works in Terragen 2.

[bobbystahr]

I echo all the previous comments and emphasize the YOU ARE MY HERO part...learned more in the short time viewing that than in all my experiments...well done man.. ...

[Seth]

great job !!!

[dandelO]

Cool, thanks for the pleasant responses, everyone!

Dune: Good idea, I'll get around to some more examples shortly, I have another couple of images to update at the end with I think. Then, I'll think about alternative lightings. This is still a kind of limited set of examples, focusing on GI on surfaces and not really the atmospheric side of the envirolight, I might try an atmosphere GI comparison thingy at some point.
It serves some purpose for now, anyway.

Cheers again!

[bobbystahr]

After reviewing the video I had a light bulb moment....what is happening is a 'caustics event' as it's producing, to my eye, a very nice 'Radiosity' [a sorta holy grail render for me] render at the higher levels...am I correct or blowing smoke out my ears again?

[dandelO]

Checking the 'GI surface details' is what creates the really accurate shadows and illumination casting from the balls onto the floor. Dark shadows and bright highlights, right around the points-of-contact of each of the casting objects. I've tried with transparency shaders to generate real caustics but, no luck yet, it does appear, very nicely, with luminosity, though.

I have a couple of other renders that I'll placemark in the meantime here, both used 'GI SD' and were(roughly) the same length of render; The settings 'GI - RD=2/SQ=12 + Surface details + extra ambient light' took about 52 minutes for me to render:
[attachimg=#]
And this one, at 'GI - RD=4/SQ=8 + Surface details + extra ambient light':
[attachimg=#]
Took about an hour and 7 minutes.
Both times don't differ that much, for the large difference in render settings, when 'Surface details' is checked. It does add a lot of render time but it's worth it if you need a good, realistically lit close-up, a still life render, car showroom-type-scene, etc.

(The 2/12 render above appears flawed as the shadows seem to disappear closer to the object points of contact in some places, I noticed when it was rendering that the wall, which rendered before the objects, wasn't taking the shadows correctly, the one at 4/8 did fine and, looks very nice, I think.)

[dandelO]

render at the higher levels...am I correct

I wouldn't say that, pare it back as far as possible! but, to make the best of the lighting, don't use a GI relative detail of '1', if you require lots of important GI details.

If you mean 'higher levels' of render detail, the way I have it worked out in my head(wrongly, 9 out of 10 times) is that, to get matching lighting quality, between different render details, a relative detail of 2/2, at a render detail of '1', is equivalent(in terms of lighting detail) to GI of 4/4, at render detail 0.5. Is that right? I've never studied the actual 'relativity' to the render detail of GI relative detail.

[bobbystahr]

Hmmmm...lots to mull over here whilst I find an interior scene to try this out with...what did you use for the extra ambient light btw?

[latego]

Hmmmm...lots to mull over here whilst I find an interior scene to try this out with...what did you use for the extra ambient light btw?

...the Cornell Box http://www.graphics.cornell.edu/online/box/?

Bye!!!

[Oshyan]

Very useful reference. Perhaps add it to the wiki?

- Oshyan

[bobbystahr]

Very useful reference. Perhaps add it to the wiki?

- Oshyan

Indeed.. ...

[dandelO]

Hmmmm...lots to mull over here whilst I find an interior scene to try this out with...what did you use for the extra ambient light btw?

Here's a quote from near the bottom of the GI examples page, Bobby:

*** Extra ambience comes, in this case, in the form of a negatively scaled(inside-out), white sphere, encapsulating the entire scene(Just like a scaled down version of the default 'background' node, which you can use for this purpose in a regular landscape shot). A tiny amount of luminosity is used on this capsule-sphere(0.005). This helps to bounce more light around and add some extra lighting to everything, without increasing exposure or raising the 'Envirolight' GI strength settings, similar to the way a photographer would use a white-reflector to do the same job. Luminosity values for the reflector sphere are subjective according to scales etc, I found that at this smaller scale(a capsule sphere of -25m enclosing the 10m room) higher luminosity values than 0.01 were easily blowing-out all the lighting/shadow details, the final setting of 0.005 that I ended up with just gives a nice little boost to the ambience. Quite nice and not too heavy on the renderer.

A wee bit luminosity on this capsule sphere bounces a bit more light around the entire scene, it adds practically nothing to the render time and brightens things up quite nicely.

Oshyan: Indeed, I have already done this when I'd posted it here, it's listed under 'TG2 Tips and Tricks', the last entry so far... http://www.planetside.co.uk/wiki/index.php/Terragen_2_Tips_and_Tricks#Global_Illumination_Examples_page

[bobbystahr]

Thanks dandelO...dunno how I missed that.. ...good trick btw.. ....

[bobbystahr]

Hmmmm...lots to mull over here whilst I find an interior scene to try this out with...what did you use for the extra ambient light btw?

...the Cornell Box http://www.graphics.cornell.edu/online/box/?

Bye!!!

LOL..thanks but I meant one I have on my drive already.. ...