Aye, we all know there are all kinds of crazy techniques for smoothing out images, and increasing clarity. I'd like to pool some of them together and make some comparisons, for I've recently come across a very powerful tool for really speeding up my production time. It's a set of filters called Kai's Power Tools. KPT6 is the set in question, and the filter I'm using is called "KPT6 : Equalizer", and is basically a graphics equalizer for blurring pixel radii instead of for adjusting sound spectrums... First off is the non-aribtrary yeah-I-know-it-doesn't-prove-anything test. This scene I brought up awhile back while messing with lighting. The lighting quickly became too complex for my 'puter to handle. This scene took 31 hours to render, BEFORE reaching the single, regular-old AA pass. Cool part is, I like it without AA. The sad part is, there's only two lights in the scene, NO soft shadows, and only one of the lights is casting shadow. So why 30 hours for one scene? The reason is volumetric clarity. Sure, I could make streaks in Photoshop in ten seconds and have it look similar. But it's not the same! When you do it correctly, IN the scene, you get real inteeractive shadows. Something you can't get or reproduce in postwork... So I took a tree and placed it between the scene and the off-scene volume spotlight. This tree's leaves are what's breaking up the volumetric light into rays. Seems simple enough, but with this particular light there was massive artifacting even at 50% Volume Quality. So I cranked it up to 66%, and it got rid of the artifacts, but at a dreadful time-cost. Which led me back to Equalizer. There's no way you can convince me to let this stupid scene render for another 70 hours just to get an AA pass done! So we'll try a few workarounds and see what happens... Here's the render in question. 31 hours, regular AA but NO AA pass. 5.25M polys, 66.5MB scene file size. JPG compression in Riptide set to 20, meaning it is "lossless" in terms of detail (hopefully!).

For those of you who haven't seen this before, it's from the original pioneers of Bryce. Or at least from the same company. This is KPT Equalizer, a filter you can use inside of Bryce (Terrain Editor, anyway) or in Photoshop/PSP. It basically allows you to determine a blur rate between different pixel depths, all at once. Similar to running a gaussian blur filter, for example, but on multiple distances with different amplitudes. Also are the contrast & bounded sharpeners, but we'll get into that later. In short, it's a simply amazing and dynamic filter for cleaning up color and contrast in an image...

And here's the image in #1 with those light settings from Equalizer applied... Look at the image, can you tell if it's not Anti-Aliased or not? I mean, I'm telling you that it isn't, so you know. But at a glance?

And here's the difference between the original and the filtered image in #3. You can see that although subtle, the filter's effects are quite visible...

The next question I asked myself, "Am I just blurring this thing into LOOKING like it's been semi-antialiased?" So I took the original in #1, and ran a Gaussian Blur at 1 pixel radius on the image... The top one is the EQ'd image-chunk, and the bottom is the Gaussian Blur image-chunk, same selection for both... (again, the .jpg compression on all these is luckily set to lossless, and still below the 200KB limit somehow... Riptide rules!)

Nice one LSD, I use KPT 6 all the time, they are unreplacable, one of my favorites is a gradient lab ! :D Sometimes "Virtual Photographer" filter (which is free) can be handy too :)

Aye, generally I use EQ after I'm done compositing. I think on this scene, I'll be using it before the compositing, and then when all that's done. I still have to run the regular, Non-Volumetric render behind the Volumetric one in #1 here, and all that on top of the distance render, and on and on... Really, the point to all of this is to save time! I know that the image in #3 isn't quite as smooth as it would be if I had let it finish the AA pass, but it's looking pretty smooth, and I'm not sure but I might just like it better that way. Thing is, Anti-Aliasing algorithms aren't really a mystery. And it's likely that the KPT people used much of this math in Equalizer. Aside from EQ not actually KNOWING where the object's edges are, it seems to have some similar effects as AA... Of course, this is just one type of scene. I'll do some more arbitrary tests in a bit with harsh-contrast edges and objects, to see if this style can help with those kinds of renders also. Here's the scene with no volumetrics, and a regular AA pass. Render time : 45.38. Much more realistic, but still too slow to animate...

I sometimes like KPT bit better (differs from case to case), cuz it actually does not fail on almost horizontal lines (edges), which every now and on happens with Bryce 3D AA effect :)

And the difference betwen the Volumetric and the Non-Volume scenes... Notice the single-pixel sprays, where the Anti-Aliasing from the Non-Volume image cleaned things up.

Aye, I agree with you there, Kemal. There are advantages to either method, it's nice to have a few different ways to do things! Mostly, I'm concerned with speed. Often-times I've heard of people doubling their image size at render time, just to try to get some kind of smoother results. I've seen it work, but I've never seen it take less time necessarily. In this case, rendering a double-sized image with the Volumetric light on is not possible. Rendering a Volumetric with no AA, and then compositing it over the non-Volume with AA, produced similar results to full AA in about 1/3rd the time it would take to do the whole scene with Volumetrics. Also, if you throw in the Equalizer effects, you end up with a nice mix of techniques, and it makes for a really soft render. Mostly i'm bringing it up because a lot of people don't feel comfy with Volumtric lighting. It takes FOREVER on Bryce, and in most other programs it's not much different. Here's a pre-post-work composite, layers are: Distance on bottom, Non-Volume AA render in the middle set to "Hard Light", and the Volumetric EQ-filtered image on top set to "Lighten". Any better than the image in #1, at the top? Notice how the volumetric light rays tend to blur out the details behind them, and the areas of shadow are starker and crisper... Adds a bit of depth to things. Wwhat I'm trying to say is that it's not always necessary to let the volume pass finish all the way. Get your lighting detail, then run it as a "Lighten" layer in post, on top of the non-Volume render. Boom! You've saved yourself hours, in this case DAYS, of downtime.

Yep, I feel you there, volumetrics are tricky, it is realy play between quality setting, and rendering parameters...

The higher you go with quality less rays per pixel and ray depth you need to have in order to compensate, if you go too low it will not look good either, so, it is some kind of balance you seek for which is gonna give you most decent results :D

Another thing to have in mind: optimizing your models and textures before rendering is very important ! :D

Message edited on: 04/18/2005 03:45

Attached Link: http://www.renderosity.com/viewed.ez?galleryid=935626

I finished the filtering, and posted a "completed" version in the galleries at the link. It's quite a bit different from the Bryce renders, hope you like it... Aye, but alas, Bryce has almost no optimization methods... When it comes to moedling, the only way to save RAM is to use mirrors and smoke! This scene is, luckily, pretty tiny at only 5 million polys. A 45 minutes render is just about standard 'round here...

Great tool there, I've used Kai's stuff quite a lot.