Friday, November 4, 2011

Last Chapter Written (more or less)

A big milestone today - I completed the last full writing on the chapters in the book. The only thing left is to structure the interviews, and thanks to the help of Alex Kozeki, who is transcribing them, that should be short work (fingers crossed). I'm feeling like I may be coming up for air from this project soon. Hooray!!
Here's another image, this one demonstrating reflections and refractions, and using high dynamic range, image based lighting.

Saturday, October 22, 2011

Almost there

This past month has been extremely busy, but the book is making progress. It can be rather difficult to fit it in around my many other life obligations, being full-time work and family. Along this line, is my thought of the day.

Thought of the day:
If you begin a large endeavor, you had better love it or you will not have the stamina to finish it. When the road starts getting long and you really wish you were already done, it is your initial fire and  belief in your project which will keep you going. For animators and CG artists, I have heard this in terms of creating your own short - that also can be a ton more work than you expected. Absolutely LOVE your idea or your project may very well die on the table, so to speak, half or 3/4 done because no team member had the stamina to finish. Someone out there is relating, I'm sure.

Other Thought of the Day:
Here's my other thought on a very long project - just keep putting one foot in front of the other. This particular book has been such a beast to write - at about 700 pages and about 2 images per page - that I truly have while in the middle of writing not known if or how I could possibly finish the darn thing. However, while climbing a mountain is not so easy, taking the next step is. Just a step... and another step... and another.... and eventually, there is the finish line in front of you after all. I believe that is an old adage:  "How do you cross the desert? (Answer) One step at a time". I like the other version myself "How do you eat an elephant? (Answer) One bite at a time".

Image of the Day:
Here's a render demonstrating the advantage of high dynamic range environment maps. Since high dynamic range images contain a larger range of data, they contain what are known as "superwhites", which are values above pure white. You will not see these values until the image is dimmed down. In the case of a digital reflection, what this means is that when the reflection is dimmed, you will still detail which shows up in the brightest areas of the reflection if you are using a HDR reflection or environment map. If you are using a regular, low dynamic range (LDR) map, these area will grey out and look unrealistically flat. The following image demonstrates this:

The center vase is at full reflectivity. The vases to the left and right are both at .3 reflectivity - they are identical but for the reflection map. The vase on the right uses a HDR reflection map, while the vase on the left uses a LDR map. Notice the realistic detail in the highlight on the right vase.

Monday, September 5, 2011

Another few Chapters in progress

I'm currently writing three chapters simultaneously on technique. The three chapters are being developed together because they were initially only one chapter. After writing the rough draft I realized the chapter would be much too long and split into three chapters. Amazingly, about another 100 pages. This is not a trivial book.
I am having alot of fun writing these chapters. These chapters are on technique and represent the "nuts and bolts" of digital lighting. They cover intermediate to advanced technique. I enjoy writing about the advanced technique the most, because sharing them is one of my motivators for writing the book. Some of the techniques in the book I have not found in any book, in any tutorial, ANYWHERE - yet they are part of the staple diet for those who are experienced lighters working in high end lighting. People learn these techniques on the job, from others working in the field. Trade secrets in a way, only I would very much like the secret out for those who love this subject as much as I do and are looking to get in to the field. I remember all the people who shared their knowledge with me and "giving forward" is the primary reason I like teaching. I know that for some, the advanced techniques are going to be to confusing. But for others, who have the basics solidly under the belt and a hunger to know more, they are going to love to learn about them, and this is who I am gearing this section for.
I haven't much in the way of images yet as I write the text then make the pictures, but I will leave this post with a tip for the day.

TIP for the Day:
When developing your lighting, be sure to add complexity only as needed. Complexity, when it comes to digital lighting, includes linking lights, rendering in passes, and the like. "Needed" means that it gives you a specific visual advantage or control that you wouldn't be able to get otherwise and which is necessary for the quality of your project. Never add complexity "just because", such as because someone has told you that is how the pros do it.

Sunday, August 21, 2011

Another day, another dozen renders

I believe I can slightly prematurely say I have finished the chapter on Global Illumination. I am finishing up the last few renders, and need to add the summary, but other than that I'm done. Barring revisions (always something isn't there?). This chapter was a beefy 50 or so pages and full of more recent technique which required additional research on my part. Keeping up with technology is an ongoing job, as everybody knows it is a moving target. Luckily for me I'm endlessly fascinated with the subject. I believe there is far more lighting trivia in my head than is good for a person. I should be a fraction as well informed about world events and I'd be a much more interesting conversationalist. Ah well.
Here are some lovely renders using reflection occlusion. Most digital lighters know of ambient occlusion, but reflection occlusion is lesser known, so for those who haven't used it here's an introduction.

Two digital renders. On the left is has no reflection occlusion, on the right has reflection occlusion
That little frog again. he's alot of fun ;)

Here's a tip for the day:
When you are trying to solve a problem: Divide and Conquer!
Narrow it down so you can isolate where the problem is. It is much easier to find a needle in a small handful of hay than in a haystack.
To isolate the problem in a digital render, I often make whatever I'm working on some crazy color so I can see it better. My favorite crazy color for debugging is magenta. Here's an image with the ambient occlusion turned to magenta so I can see it better.

Egg render on the left (lighting by Howard Ross, a student in my lighting class. nice eggs, Howard!), egg render being debugged for occlusion on the right (did anyone think those were real eggs?)

Friday, August 19, 2011

More thoughts on Global Illumination

As I sit and wait for another really long render, I am looking for things to keep me productive. Not sure if the blog qualifies, but what the heck.What to do when waiting for a render. General  summary: Keep busy.
My thought on Global Illumination is "Wow that looks nice!" Followed by "Good lord, it is only how far along?" as I wait for a full res, high quality render. While the big studios have just recently gotten to the point where they are using GI most of the time, this is made possible by two things the average Jane like me doesn't have. One is a gigantic renderfarm (Pixar ramped up to 12,500 cores for Cars 2), and the other is proprietary software that makes things go a bit faster which they do not always share with me and you.

Tip of the Day:
On another track, as a professor I often see ambient occlusion used incorrectly. So here's the correct and incorrect ways to implement it. Ambient occlusion is often multiplied with the beauty pass in the composite. This is incorrect. It actually should only affect the ambient contribution  or else you will end up with overdone occlusion in the areas of direct light.
Occlusion multiplied by the entire render leads to too much occlusion. Notice the dark shadow in front of the clown.

In this example using render passes, you need three passes: Occlusion, ambient only, and direct light only. Occlusion should affect ambient only, then be added to the direct light for better results.

Wednesday, August 17, 2011

Starting a blog

At the suggestion of a friend, I am starting a blog about the writing of my book Illuminated Pixels: the Why, What, and How of Digital Lighting. I must admit I'm not much of a blogger, but here goes. I am in the final stretch of the book, and it has been a very long haul. I first thought to write a digital lighting book at least 5 years ago and began dabbling with chapters and outlines. i didn't really get down to business until about 2 years ago, but still - it's been a long time coming. I've had to update material as I go along, as the area of technique is always changing. Especially in the past about 5 years things have really changed in high end digital lighting. However, the fundamentals remain the same. And the book is about fundamentals as much as anything else.

Right now, however, the chapters are about technique, and I'm rendering images showing various examples of image based lighting. And gees do they take a long time. i decided to make them smaller ;)

Render Tip of the day: Reducing your render by 1/2 the size saves 3/4 the time. So my 8 inch wide, 40 minute a frame just became a 4 inch wide, 10 minute a frame render.

Image of the Day:
Simple scene (thanks to the students at SCAD-Atlanta for the frog and fly models) rendered with a single environment light and full global illumination.