Grenadian James posts world-leading time in 400 metres

first_img Good experience DES MOINES, Iowa, (CMC): Grenada’s Olympic champion Kirani James produced a world-leading time to win the men’s 400 metres at the Drake Relays here on Friday night, and continued his fine start to the new international season. The 23-year-old stormed to 44.08 seconds – the second fastest time ever run in the first four months of a year – to edge American nemesis, former World and Olympic champion LaShawn Merritt, who was timed at 44.22. James’s fellow countryman Bralon Taplin claimed third in 44.92. “It shows that I’m on course to do some great things so long as I don’t take anything for granted and keep on doing the right things for the rest of this season,” James said following the performance. “I’m happy with the time, I’m happy with the performance, and I’m just happy to be here at Drake. I always have a good experience here, so all is well.” On a chilly day at Drake Stadium, James showed little negative effects from the weather. Running out of lane five, with Merritt in lane four, James held a narrow lead heading into the final 100 metres and managed to hold on despite Merritt nearly pulling level. The win came against the backdrop of James’s impressive 44.36 run at the Bahamas Invitational in Nassau two weeks ago, and sent a strong warning to his rivals, with attention already on the Summer Olympics in Rio. James, who dominated the London 2012 event but finished third at the Beijing World Championships last year, said he was much more prepared for this year’s showpiece. “Now is a lot different. I understand the event a lot better. I know the athletes more,” he said. “It’s a lot more technical … people look out for you to perform, and that’s part of it.”last_img read more

Is Modeling a Four-Letter Word?

first_imgRELATED ARTICLESEnergy Modeling Isn’t Very AccurateWUFI Is Driving Me Crazy A Brief Introduction to WUFI, in 5 Easy PiecesMakin’ WUFIThe Principles, Uses, and Limitations of WUFI Energy modeling has gotten a bad reputation in the home performance world. One conference I’ve attended has gone so far as to say that it’s “outside the sandbox” of topics presenters can cover. They want to see data, not modeled results. And they have good reason for that.The two kinds of physicistsComing from the world of physics, I have a different perspective. (OK, I had a different perspective even before the book Asimov on Physics opened my eyes to the beauty of the universe when I was 17.)In physics, modeling is essential. In fact, if you go to any physics department, you’ll find one of the two kinds of people: those who can extrapolate from incomplete data.But there’s another two kinds as well: the theorists and the experimentalists. They need each other.Without experimentalists, theorists would go completely off the deep end. (Some say they have with string theory.) Think of Aristotle here, with his peripatetic scholars relying only on logic to find explanations for physical phenomena and never bothering to test their ideas. It took nearly 2000 years for Galileo to usher in the era of modern science by rolling balls down inclined planes. The harmony of modeling and dataAlbert Einstein was the consummate theorist. He developed the special theory of relativity by imagining what it would be like to move along with a beam of light at the same speed the light was traveling. That was his idea of doing an experiment, and it even has a name: Gedankenexperiment, which means thought experiment in German.Einstein’s general theory of relativity was his expansion of special relativity. He published it in 1915, and that’s when the idea of the curvature of space-time was born. An important fact about this theoretical paper was that he based it on the available data. For example, it explained an anomaly in the orbit of Mercury.It also was testable. Four years later, Eddington confirmed the curvature predictions when he found a deflection of starlight around the Sun during an eclipse.On the other hand, he considered the “biggest blunder” of his life to be the introduction of an unnecessary “cosmological constant” simply to conform to the prevailing idea of a static universe. Had he believed his equations instead, he could have hypothesized the expanding universe 14 years before Hubble discovered it.That’s how science works. Ideas get thrown out there. They get tested by experiments. One negative result can disprove a hypothesis. No amount of data can ever fully prove it, but the more data you have, the more confident you can be in the validity of the idea.The problem with energy modelingNow, physics is a science. Home energy retrofits rely on science but are not science themselves. The late Phil Jeffers, an occasional commenter here, used to complain about turning home energy audits and retrofits into science projects. He had a good point.It’s easy to go too far with modeling, and Michael Blasnik has exposed the flaws with energy modeling. He’s looked at program results in Minneapolis, Oregon, California, and other places and found that most modeling overpredicts the savings, sometimes unrealistically so. No matter how good a home performance contractor is, for example, they’re never going to cut someone’s energy bills by 125%. (You can download the pdf file of his 2013 Building Science Summer Camp presentation, Lies, Damned Lies, and Modeling.)Likewise, John Proctor recently said, “We don’t need an energy model to tell us that an uninsulated house needs to be insulated and a leaky house needs to be sealed. Just fix it!”Is modeling useful?Joe Lstiburek has also been critical of modeling over the past few years, especially hygrothermal modeling with tools like WUFI. His company, Building Science Corporation, does WUFI analyses, and he’s open about when it should be done and when it shouldn’t. “I’m hoping two-thirds of the modeling that’s being done now won’t need to be done,” said Lstiburek at the 2013 BSC Experts Session, “and the modeling that’s needed is done correctly.”Lstiburek was talking about hygrothermal modeling, mainly for new construction projects with assemblies that don’t have much of a track record. Think R-40 truss walls and R-60 insulated rooflines. Doing some modeling ahead of time can help avoid costly mistakes.Jeffers, Blasnik, and Proctor were talking mainly about existing homes. The problems are usually obvious, as in the photo below, and we’ve got several decades of experience in weatherization and home performance contracting to help guide us in fixing them.The problem comes in with programs that require modeling so the program sponsor can justify the expenditures. We could spend a long time discussing this issue and how to fix it, but this article has already gone on far longer than I had intended and is threatening to suck up the rest of my day the way a black hole sucks up everything, including light, that gets too close. (By the way, black holes are another cool thing that came out of Einstein’s general relativity!)So let me conclude by going back to the title and saying that modeling is not a four-letter word. We need modeling. And we need real data from monitoring projects. We also need to keep it all in perspective and keep the focus on the results.Here’s another perspective: What good would physics be without modeling? Allison Bailes of Decatur, Georgia, is a speaker, writer, energy consultant, RESNET-certified trainer, and the author of the Energy Vanguard Blog. Check out his in-depth course, Mastering Building Science at Heatspring Learning Institute, and follow him on Twitter at @EnergyVanguard.last_img read more

Understanding Keyframe Interpolation in Adobe After Effects

first_imgIntroducing InterpolationWhen you apply keyframes to a layer, After Effects will interpolate the values between them. For this particular animation, I’m using two simple position keyframes to launch my rocket. The keyframes are moving the rocket through space over a period of time. I can precisely control how the rocket moves through space and time by changing the interpolation methods.After Effects uses the Bezier interpolation method, allowing you to control keyframes with bezier handles. I can switch the interpolation method via the Keyframe Interpolation dialogue box, which gives you options for both spatial and temporal interpolation settings. While this might seem a little technically intimidating at first glance, it’s actually quite simple once you understand the lingo. Essentially, these methods specify how After Effects applies bezier handles to keyframes. Let’s have a closer look.Spatial InterpolationSpatial interpolation, as the name implies, refers to space. You can view and manipulate spatial keyframes in the composition panel. If I move the end keyframe in the composition panel, the keyframes don’t move on the timeline panel. This is because the rocket is still traveling over the same period of time, just a different distance. To compensate, it will either travel faster or slower, depending on which direction I drag the keyframe. You can see the change in speed reflected in the speed dots on the motion path. Each dot represents a frame, with more dots signaling a slower speed.Temporal InterpolationOnce again, as the name implies, temporal interpolation refers to time. When you move keyframes left and right on the timeline, you’re moving them in time. For example, if I move the final keyframe in my rocket animation, the keyframes in the composition panel won’t move. There will, however, be a change in the speed dots between the keyframes. As I move the end keyframe closer to the beginning, my speed dots will become few and far between. This is because the rocket is traveling the same distance over a shorter period of time. Therefore, it must move at a much faster rate. The speed dots will reflect this. Now, let’s tweak the animation.Refining the AnimationCurve the Flight PathWhile I have my keyframes in place, the animation looks about as real as Dwayne “The Rock” Johnson in The Scorpion King. To lend the rocket launch more realism, I need to adjust the interpolation.First, I’ll add a quick curve to the flight path of the rocket, making it turn slightly to the left after it launches. To do this, I’ll grab the Pen tool (G) and place an additional keyframe to the motion path, roughly where I want the turn to begin. After the new keyframe is in place, I’ll select the final keyframe and move it to the left. You’ll notice right away that the motion path is not as smooth as we want it to be. I can fix this with the bezier handles. To straighten out the rocket’s flight path, I’ll use the bezier handles of the last two keyframes.Once I have the keyframes in place and the motion path tuned in, I still have a few problems. First, the rocket is not facing forward. I can quickly remedy this by grabbing the layer and selecting Layer > Transform > Auto-Orient > Orient Along Path. This will actually face the rocket to the left, so I’ll have to rotate by 90 degrees to properly face the rocket forward. My second problem has to do with the speed. It’s still a very unnatural movement, so now I’ll focus on adjusting my keyframes temporally.Ramp Up the SpeedWith my motion path set, I now need to adjust the speed of the rocket to give it a more organic launch. As with most rockets, I want it to slowly ramp up in speed during takeoff. I can fine tune the speed with the Graph Editor. To open this display, I’ll simply press the Graph Editor button in the timeline panel. This interface will show me speed and value changes over time. To make sure I’m viewing the speed settings, I’ll press the Choose Graph Type button and select Edit Speed Graph.Once in the Graph Editor, I will select the position property of my rocket layer to bring up my keyframes in the display. To properly change the launch speed, I need to change the middle keyframe to Rove Across Time. This means it will not lock to a specific time but, rather, adjust based on the timing of the first and last keyframes. To make the keyframe rove, I’ll right-click it in the comp panel and select Rove Across Time. I’ll need to readjust my motion path, and then I’m ready to change the speed.To slowly ramp up the speed of my rocket, I’ll move the keyframes and bezier handles in the Graph Editor until I get a movement I like. For this particular animation, I want the first keyframe to be set to zero pixels/second. Then I’ll grab the bezier handle and drag it as far right as possible. This will slowly ramp up the speed to the next keyframe. Voilà! My rocket now has a smooth takeoff.Looking for more After Effects tutorials? We’ve got you covered.5 Ways To Create A Background in After EffectsVideo Tutorial: How to Stitch 360 Footage in After EffectsVideo Tutorial: How to Loop an Animation in Adobe After EffectsAnimate A ‘Top 10 Countdown’ Screen With After EffectsAnimate Clean Commercial Graphics in Adobe After Effects Keyframe interpolation can improve the realism of your animations and save your workflow some time. Find out how in this video tutorial.Understanding keyframe interpolation in Adobe After Effects will help bring your motion graphics to the next level. Not only will it give your animations more realism, it will also significantly speed up your workflow. In this tutorial, I’m going to show you how to use keyframe interpolation to give a simple animation more natural movement. In particular, I’m going to give a rocket graphic a more realistic takeoff. In the process, you’ll learn about the importance of spatial and temporal interpolation, and the difference between the two.Let’s get started.last_img read more