Hey people!

Albus Dumbledore

I just got home from watching Harry Potter and the Half-Blood Prince. I must admit I was kind of anxious about watching it, first of all, because I missed the premiere! I had never missed a Harry Potter premiere before! NEVER-EVER. Second, everyone who assisted the premiere hated the movie, so I was like ”Uh, maybe I waited in vain”. I didn’t. I absolutely LOVED it! I feel like reading the whole story all over again! Such great screenplay, script, everything!

Everyone’s argument to hate the movie is ”THE ENDING WAS LAME!!!111oneone”; but I’m pretty satisfied, I mean, the whole Dumbledore dying scene was exactly the same as in the book, and I quote…

“Severus… please…”

It was brilliant! I really don’t have anything negative to point out about the movie. The movie was great, the company was great (Monique, Alessa, JD and Pepe) and, what can I say. Tonight was a great night.

I’m glad everything seems to be going alright. I feel peaceful. For some reason. And I like it.

Studying physics theory tomorrow, finals next week…

That’s all for now, love you readers <3

http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/apollosites.html

Just in time for Apollo 11′a anniversary, NASA has released the photos that should for once and for all end the lunar hoaxers claims of a faked moon landing.

In June, NASA’s Lunar Reconnaissance Orbiter (LRO) went into orbit.  Its cameras are the best ever installed on a lunar orbiter … so good in fact that they can take pictures of the lunar excursion modules (LEMs) that landed on the moon.  As of the time NASA released the photos, there were pictures of Eagle (Apollo 11), Antares (Apollo 14), Falcon (Apollo 15), Orion (Apollo 16), and Challenger (Apollo 17) had been imaged (Apollo 12’s Intrepid has not been imaged yet, and of course Apollo 13’s Aquarius never made it to the moon).

Some of the photos are fantastic … in some cases, scientific equipment is visible, as is a disturbed path from the LEM to scientific equipment (footprints and/or tire tracks … in the absence of wind, those tracks will be around a very long time).

Another victory for science, fact, and education!

An excellent question posed by a Scot, a reader at The Friendly Atheist. While Richard gives a fine answer supposing belief in a supernatural version of Karma, I find several of the comments interesting and more akin to the way I’ve used the term. Gary says:

Actually, the word “karma” is sanskrit and simply means “action”. Actions have effects. In Hinduism and Buddhism, some actions have beneficial effects and others have detrimental effects. Effects of actions in the current incarnation may have effects in later incarnations. In these religions, karma is a regarded as a law analogous to physical laws. A supernatural agent is no more required to administer karma than is required to administer the laws of physics theory. In Buddhism, which doesn’t have a belief in a creator god, one’s fate is entirely up to oneself, based on one’s actions. While a scientifically minded skeptic may not believe in rebirth, it is hard to claim scientifically that actions do not have consequences.

In fact Victorb does relate the concept directly to physics theory:

If you’re into modern physics theory, you should be able to see how this concept of karma can be mapped onto Hugh Everett’s many worlds interpretation of quantum mechanics. The branches that your reality takes as you moves through time are dictated by what is possible based on all your existing choices.

But trixr4kids is having none of it:

For the average educated, spoiled Westerner, sure, virtue is its own reward–but that’s not karma. Luck must be factored into the equation. “Karma” is an egregious concept (even in its watered-down versions, I think) precisely because it disregards the fact that suffering and hardship are random and tends to equate happiness with virtue.

I do think there is a connection between happiness and virtue. But the corellation isn’t as strong as it’s often made out to be. Used properly the idea can be inspiring, but as an absolute philosophy it can be downright insulting to those who have suffered hardships through no fault of their own (which is not to say we are relieved of all personal responsibility for our happiness – some hardships are indeed self-inflicted).

Do I run updates from the server into keyframed objects on the client?

Do I run updates from the client into keyframed objects on the server… The problem as far as I can tell with keyframed objects is that they have infinite mass when other things collide with them, and thus when client actors run into them on the client side they would have no effect on them, while the client actor would stop dead and/or be moved by them..

The solution thus seems to be that the client actor only creates local copies of static objects, e.g. terrain and static containers etc, that are keyframed during animations… That seems somewhat limiting though, as keyframed animated containers would need keyframe definition files… that might be possible without too much problems perhaps… So the sequence might go like, client has static geometry and a character controller. The character controller is replicated to the server as a keyframed mesh and thereby affect the environment with infinite force, but the client only receives position updates for world objects for use in graphical form with no physical manifestation.

It’s obvious from experimentation that the character controllers can’t reside on the server, the jerkiness would drive local server players nuts in short order, but they have to affect the environment in some way…. I should continue that way, basically having the client take care of the movement of the character, and sending position updates to the server each frame, keeping the server completely and absolutely separate even when running as a separate thread in the same application instance.

Blocking calls from the client stopping the server is not acceptable. I guess I could let the server run and wait for each frame to finish, locking the client meanwhile, but no, that’s not acceptable really… Should it send velocity updates? Good question, I might as well, an additional vector is not really a great deal of extra bandwidth but I don’t see what the server is gonna do with it really.. It doesn’t seem to make sense really, as the server will check each update the last position of the character and calculate velocity from that. It might prevent the shit from flying around if the character misses a few frames and suddenly updates and gets a huge velocity, but that should be solved from timestamps on the last updated time thing I’ll have put on the server side character tracking information struct in any case.

I guess I’ll go whatever way I go.

Appearing to have stepped out of a 1970s time machine, Paul Davies gives a stimulating talk on the cosmic mysteries.

Intellectual wavy gravy:

And Part 2:

In the last installment, we gave a high level overview of rotational energy, momentum and moments of inertia. None of these things are covered in modern “physics theory” engines. What we call physics theory engines would better be called “rigid body” engines. This means that we need to devise a way of dealing with these attributes.

Moment of inertia depends on the distribution of the mass relative to the pivot point. This means that you can simply define a number and leave it at that. You have to track your mass distribution. We already have a tool that gets us part of the way there; the 3D mesh from the model(s). If we have a character model and a sword model attacked to a dummy node located at the character’s hand, we have two defined objects and a constant mass, bit the moment of inertia changes every time the character moves. The brute force approach would be to devise a mathematical model – a single equation – to determine the moment of inertia at each. Our swing motion is a smooth motion through an arc and the position and orientation of each mass in that motion results in an and ugly and expensive to solve equation. This is impossibly impractical for each motion permutation, so we’ll impose a couple of tricks.

The Horse can be approximated as a sphere

The above statement means that we don’t need to be exact and we can get away with a lot of approximating. Specifically, we’ll do two things.
We have explicit time slices where we know the exact configuration of the masses in our character/sword system because we have the animation key frame data. We’ll solve I for each key frame only and hand wave mechanics/approximate it. This is also how physics theory engines approximate rigid body motion. They don’t solve Hailtonians or Lagrangians. They step through time slices.
We need to have the mass distribution of each object. It is right there in the 3D mesh and we can pull it out with an algorithm. We can even go a step further and reduce that mesh shape to a collection of points representing the mass distribution of the object. The moment of inertia for a point mass is simply its mass times the distance from the axis of rotation. This makes for a speedy calculation.

The leftmost image is the blade from the sai model that eq2001 put up on turbosquid. The middle is that model with a rough approximation of its mass by individual point masses superimposed. The rightmost image is the resulting “mass cloud”. At each keyframe, we can now easily determine the total moment of inertia. This allows us to calculate such things as angular momentum, kinetic energy of rotation, etc.

In fact, we can take it a step further. If we agree that a character’s “strength” attribute defines his/her ability to generate torque and that a given character would have a “terminal rotation velocity”, where the motion simply can’t accelerate anymore, then we have a few more tricks up our sleeve. If the motion has not yet reached its terminal velocity, then we can – in principle – shift the keyframes around in time. Weaker characters, or ones wielding heavy weapons, now swing slower than strong characters or ones wielding light weapons. We can call this shifting of keyframes an “animation profile”. It is essentially a list of time/space shifts in the keyframes. This requires a change to the way that clients typically handle animation calls; namely that an additional parameter of the animation profile list.

If time bends, so does the truth. Truth and time are symbiotically connected, intertwined, fluid and invisible like gas, as if there’s an undetected gravity that mutates truth as it travels through moral and physical space. Often truth is like a ghost, what was the truth a moment ago is no longer quite the truth.

Microsoft Research, in collaboration with Microsoft Corp. Chairman Bill Gates,  makes the Messenger lecture series by physicist Richard Feynman freely available to the general public for the first time.  The Messenger Series explains the relation of Mathematics and physics theory.

If you have ever read any of his books, you will really enjoy seeing and hearing the man in action.

To view the lecture series, you must first download and install the Silverlight plugin, similar to installing a Flash plugin.  However, installation is simple and works seamlessly on a Mac.  View the Lecture Series