When I was at Google I wished they had a few 'uncoders', people who made it their goal in life to leave the source tree with fewer lines of source than they found it.

True story: I went to a talk given by one of the 'engineering elders' (these were low Emp# engineers who were considered quite successful and were to be emulated by the workers :-) This person stated when they came to work at Google they were given the XYZ system to work on (sadly I'm prevented from disclosing the actual system). They remarked how they spent a couple of days looking over the system which was complicated and creaky, they couldn't figure it out so they wrote a new system. Yup, and they committed that. This person is a coding God are they not? (sarcasm) I asked what happened to the old system (I knew but was interested on their perspective) and they said it was still around because a few things still used it, but (quite proudly) nearly everything else had moved to their new system.

So if you were reading carefully, this person created a new system to 'replace' an existing system which they didn't understand and got nearly everyone to move to the new system. That made them uber because they got something big to put on their internal resume, and a whole crapload of folks had to write new code to adapt from the old system to this new system, which imperfectly recreated the old system (remember they didn't understand the original), such that those parts of the system that relied on the more obscure bits had yet to be converted (because nobody undersood either the dependent code or the old system apparently).

Was this person smart? Blindingly brilliant according to some of their peers. Did they get things done? Hell yes, they wrote the replacement for the XYZ system from scratch! One person? Can you imagine? Would I hire them? Not unless they were the last qualified person in my pool and I was out of time.

That anecdote encapsulates the dangerous side of smart people who get things done. Sometimes they are too smart and do too much. So when the question of 'invention' comes up I like to wrap it around discovery. Sort of 'Tell me about a time where you built something that you had no idea how to build it when you started.' Things I look for are how did you go about discovering the path? What resources did you engage? What options did you consider? When did you 'call the vote'[1] ? My experience has been that things built by two or three people, working as peers, are often much 'better' (meet the needs better, cover more cases, have a more consistent model) than things built by one person.

[1] 'call the vote' - in parlimentary terms when continuing debate will not help you make a better decision, it is time to stop debate and to vote on the decsion. Good leaders look for this point, and move forward once all the voices have been heard.

I think what they're doing is great, but I see two problems with their presentation. First, computer rendering techniques are extremely well understood and well researched. We've picked the low hanging fruit, much of the high hanging fruit, and everything in between. There is no "groundbreaking new technology" to be invented. They're converting polygons into voxels (although each voxel is probably a sphere for cheaper computation), and using software ray-tracing to render in real time. Since ray-tracing is trivially parallelizable, the multicore technology is just about there now. A 12-core machine will give just about 20FPS. The reason why they can get away with an incredible amount of detail is that ray-tracing diffuse objects is fairly independent of the number of visible polygons in the scene.

The second problem is that 10^4x improvement in level of detail does not mean 10^4x aesthetically pleasing (or in fact, more aesthetically pleasing at all). Ray tracing gets very expensive the moment you start adding multiple lights, specular materials, partially translucent materials, etc. It is very, very difficult to do that in real-time even with standard geometry, let alone with 10^4x more polygons. This is why their level doesn't look nearly as good as modern games despite higher polygon count (compare it to the unreal demo: http://www.youtube.com/watch?v=ttx959sUORY) They only use diffuse lighting and few lights. In terms of aesthetic appeal of a rendered image, lighting and textures are everything.

Furthermore, one of the biggest impacts on how aesthetically pleasing a rendered images looks is made by global illumination. That's also something that's extremely difficult to do in real time with raytracing, but is possible with gpu hardware with tricks. The trouble is, these tricks look much better than raw polygons.

Again, I love what they're doing. Real-time ray-tracing is without a doubt the future of graphics, but it would be nice if they were a little less sensational about the technology, and more open about the limitations and open issues.

The article starts off on the wrong foot.

"Every right-thinking person abhors child pornography."

Wrong. The way child porn is defined, I do not necessarily abhor it. One 17-year-old in a legal relationship [in case anyone out there thinks age of consent is 18 everywhere, google age of consent; you're in for a shock], taking nude photos of him/herself and sending them to his/her partner, is classified as "child porn" under current federal law.

The average person, hearing "child porn", conjures images of minors being abducted and abused in some basement, or being abused by relatives. If only child porn laws were tailored that narrowly.

(I completely agree with the main premise of the article, but this bill is hardly a new phenomenon. Pedophilia (technically pre-pubescent minors), ephebophilia (post-pubescent minors) and/or child porn has been one of the four horsemen of the infocalypse[1] for many years.)

[1] http://en.wikipedia.org/wiki/Four_Horsemen_of_the_Infocalyps...

Throwing out all your code and rewriting it from scratch is like demolishing your building and constructing a replacement from scratch. It's usually not the right thing to do, it occasionally and rarely is the right thing to do, and it's always the tempting thing to do.

It's stupid to argue, "You should never tear down a building" (like http://www.joelonsoftware.com/articles/fog0000000069.html implies) and it's also kinda stupid to write an article entitled, "Why We Tore Down Our Building (And Why You Should Too)"

Neither is universally right. The right thing to do in a given situation is a difficult and complicated question to answer, and it depends on the building in question: how big it is, how well it was designed, how well it's been maintained, etc.