I completely understand your frustration but it's unfortunate that you did not first and foremost *contact support*. That's what we're here for. No question is stupid, no concern is invalid. If you have questions or problems, let us know *ASAP*! *Before* it gets to this point of frustration.
You're absolutely right that documentation should be available for the new GI settings. We'll get that taken care of ASAP and we certainly apologize for not having done that sooner. It was intended, but got overlooked in the final push to launch.
The only change for the base GI settings is "decoupling" the GI detail from the main detail, which gives you more control over GI independent from your render detail. This is useful for several reasons, in particular it allows you to maintain a constant GI detail even as you change render detail, so the GI results won't change (potentially significantly) between low detail test renders and higher detail final renders. It also allows you to reference GI settings across projects and between varying detail settings and know that they are the same. The new values are definitely different than the old ones, though loaded TG2 files should have "equivalent values" selected automatically. The documentation we'll provide will help you better understand all this and the equivalent settings to what you're used to.
GI Surface Details is handled completely differently now, as noted in the TG3 release and marketing materials. It adds a minute or two to most average-length renders (much less for low detail test renders), far from the huge increase (often doubling of render time) in TG2, and the results are also better. It's not something you should shy away from or treat at all like the old GISD. It is one of the biggest benefits of rendering in TG3, and it's enabled by default because of that, and the relatively low render time impact. Of course you can always disable it, and turn it off for your default project as well, if you want to.
Regarding render time differences, TG3 will in some cases render a *bit* slower than TG2 due to changes we had to make to support the extensive Render Elements system. But there were other optimizations made that can often make up for this, and using the newer features of TG3 such as 2D shadow maps for localized clouds can actually provide notable speed-ups. More important to your situation, *equivalent settings* between TG2 and TG3 should absolutely not be resulting in a 3x, 2x, or even 1.5x render time for TG3. Without GISD on TG3 should be generally equivalent to TG2 in most cases. When doing such testing it's critical to create the scene in TG2 and render it in both TG2 and TG3, because TG3 has some new settings enabled by default (like GISD) which can affect render times. I've just done a similar test to dandelO's and my render times are: 25s TG2, 24s TG3, for a very simple scene. Upping detail to 1 and AA6 gives me: 2m7s for TG2, 2m27s for TG3. So definitely a bit slower (about 15%), and that's not ideal, but it's certainly a far cry from 2x render time. The performance issue is something we'll continue to look into and improve, of course.
The changes to the soft shadow handling were partly rolled back in the final release, 3.0.07.0. See the final change log here, 2nd line of the 3.0.07.0 changes:
http://planetside.co.uk/tg3-release-changelogBut it should be noted that those changes should have also resulted in higher overall quality and the idea was that you could reduce soft shadow samples to compensate, in cases where the render times were higher. It was decided that the potential gains weren't worth the complexity, so we're working on better approaches to that.
Renders with Defer Atmo should look virtually identical in TG2 and TG3, as far as I'm aware. If you can provide examples where the results are noticeably worse in TG3 with exactly comparable settings, please do share that. There may well be a bug somewhere in there that we could address.
- Oshyan
