Anatomy and Art

a blog by Sara Egner

Archive for the ‘animation’ tag

The Ecliptic

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For the past year, maybe year and a half now, I’ve been making a lot of these astronomy animations for Macmillan. I really enjoy them. Most of the topics just lend themselves so well to 3D animation.  Some of them wind up being really interesting math puzzles, and you even discover very real things just playing with the settings sometimes.

In this particular animation, we wanted to show students the ecliptic, but we wanted to be able to show it to them before introducing the concept of the celestial sphere.  Most textbooks reference the celestial sphere in defining the ecliptic, so already we had this complication in how we were going to come at this.

I was also pretty challenged by the idea of how can we come from an out of orbit view into a view within orbit.  When I’m building these, I find myself setting up a lot of nulls within nulls within nulls to define different movements (orbit, rotation, angle…)  I have found that putting a camera in different levels of these nulls can be really revealing.  And in this case, I was able to go from a static camera which shared the exact position of a camera in orbit at a particular frame, so that I could switch from one camera to the next and move from that wider view into a closer view of Earth that follows it’s orbit without breaking continuity.

Fun fact: By putting the camera in a different null earlier on, I actually accidentally stumbled into a nice visualization for the analemma.  If your camera is in orbit with the Earth, and always pointed toward the sun, you can see the poles on Earth wobble toward and away from the sun, as the constant angle of the axis faces along the same XYZ coordinate in it’s orbit.  But that was a little distracting for this one.

For this one, it made more sense to go with keeping the camera on a fixed side of Earth and letting the light appear to orbit around it, even though it was actually the Earth and camera in a null orbiting the light the whole time.  This wound up being perfect for showing that transition from a heliocentric view to a geocentric one.  The illusion was already there.  And setting up a mini sun in perfect sync was easy enough.

And then, because we wanted to reference the background stars, and the zodiac constellations are literally the constellations along the ecliptic, we got to pull that in as well.  We used the spring zodiac constellations, and at first I messed this up, but when the south pole is oriented toward the sun, that’s our winter, and when the north pole is oriented toward the sun, that’s our summer, and you can see in this view that we are moving from winter to summer, so the sun would be passing through Aquarius, Pisces, and Aries.

I get better at these, the more of them that we do.  So much of astronomy just comes down to objects in motion, at vast distances, and how things look differently from different perspectives.  It’s a fun subject, and so well suited to 3D animation.

Written by Sara

July 20th, 2019 at 2:08 pm

The Moon’s Formation

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Today I finally got the go ahead to share one of the astronomy animations of late.  It looks like we may change something about the sun on the first one, but this one is staying as is.  This was definitely the crazier of the two to work on so far.  I don’t really ever get requests to crash things when I’m making bio animations.  So I did a few tests in advance of taking this one on, where I discovered the Voroni Fracture, which is super fun, especially when combined with the push-apart and random effectors.  Unfortunately, by the time we got the textures fully set and introduced a molten core, every scene that used Voroni fractures wound up taking forever to render.  There are spots where I would have liked to do it a few more times to finesse some of that stray space debris and get it just so.  But overall, I learned a lot working on this, and it was fun to try something different.

It’s been a while since I’ve been able to post anything fun from work on YouTube.  For a while there, most of my animation work was either going into larger interactives and needed that context to make sense, or was really small, and again best within the context it was being made for.

I’m looking forward to doing more of these.  And when we get things settled with that first one I’d like to show it off too.  It’s less smash and more elegant.  I think it’ll give viewers a good aha moment, and well, that’s my favorite part of working on things like this.  Well, that and the part where the details of my job involve all kinds of cool scientific knowledge.  Really, prior to making this, I don’t believe I’d ever heard this explanation for how our moon formed.

Oh, and I can’t forget to mention this awesome find for textures.  I only used them a little in this animation, but I’ve gotten good use out of the textures that are freely available from Solar System Scope.  It’s a lot like taking them directly from NASA, only these folks have already done the work of taking NASA’s telescope images and stitching them together to make a perfect texture for application to a sphere in whatever 3D program you might be using.  It’s really made working on these kinds of images nice.  So big thanks to them, and obviously to NASA.

Written by Sara

July 13th, 2018 at 9:09 pm

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The Wiggle Expression

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Recently at work, I’ve had cause to use the wiggle expression in After Effects.  If you’ve never done this, it’s pretty simple to set up.  First, open up the transform controls in your timeline for the object to which you intend to apply the effect.  Then alt-click the position stopwatch.  You’ll be prompted to add an expression in the timeline under the layer, and there you’ll write wiggle(1,20).  Actually, the numbers will be whatever you want them to be.  The first specifies how many wiggles per second you want to apply.  The second specifies the amplitude of the wiggle in pixels.

In my case, this effect was really great for bobbing around a bunch of molecules in a scene.  But I ran into trouble when I wanted to ease up the effect for more control.  To use my example again, I needed molecules to bob around in liquid, and then pass through a semi-permeable membrane, which required more control over them, and then go back to bobbing about.

screen shot of water molecules moving across a semi-permeable membrane

So, to do this, you need a slider control layer.  So you’ll create a new adjustment layer.  Then under the effects pull-down, up top, go to expression controls, and then slider control.  Then you’ll highlight the number on your expression that you’d like slider control over.  In my case it was the amplitude (see the 20 in the example).  With that number highlighted, you’ll grab the pickwick (looks like a swirl) and literally pull it up toward the slider stopwatch.  You’ll see your code change it it’s worked.

Your wiggle expression will then be defaulted to zero until you dial the slider control up.  Now you can keyframe that feature to begin slowly, or to reduce mid animation for greater position control when you need it.

Some of this is easier to understand when you see it, and doesn’t really lend itself well to explanatory screen shots.  This YouTube video by Ian Killick does a great job of showing the process…

Written by Sara

September 30th, 2017 at 10:19 am

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DNA Cloning Animation

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I recently had the pleasure of working on an animation to teach students about DNA cloning.  This is one of those exciting ones where I feel like we really added to what’s out there on this topic.  So naturally I wanted to share it here as well.

Written by Sara

June 11th, 2015 at 9:25 pm

Rodin’s Hands at Stanford

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There is a really interesting exhibit happening at the Cantor Arts Center at Stanford.  I believe it opened just yesterday, and will be there until August 3rd.  It’s called Inisde Rodin’s Hands: Art Technology and Surgery.  You can read Stanford’s coverage of it directly here.  Or you can watch this video with James Chang speaking a bit about noticing specific physical maladies in Rodin’s sculptures when he was an undergraduate, and how this project grew from that observation.  Now he incorporates the study of these sculptures into his hand surgery educational program where students diagnose and correct the maladies observed.

 

Sarah Hegmann, who I went to school with, put together this animation bringing Rodin’s hands to life as part of the exhibit.

Written by Sara

April 10th, 2014 at 8:24 pm

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I Will Learn Premiere

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Today I am making a commitment to make this the year that I finally learn to really use Premiere.  I have had it with pushing After Effects to do longer animations than it is geared for, and it’s long past time to get over my old version of Final Cut Pro falling further and further behind the times, and the new versions are not going to redeem themselves.  The truth is, Premiere and After Effects have been crafted to work seamlessly with one another.  I just have to take the time to learn those tricks.  I’m about to have a Lynda.com subscription again, and I am making this a high priority goal.  Premiere has gotten really good in recent years and I know that I’ll like it more as I learn more of the same shortcuts I had in Final Cut Pro.  It’s not like I haven’t used it at all.  I just get angry with it for not being the Final Cut Pro I used daily for so much of my life.  Now I can use this one instead.  It’s time to get over this meager hurdle already.

Written by Sara

January 30th, 2014 at 11:30 pm

Area and Volume of a Cube

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Just a nice little math visualization that I made in Cinema4D and recently posted to YouTube

 

Written by Sara

November 22nd, 2013 at 8:36 pm

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Rocky

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I started to post something tonight, but had a moment of doubt about my terminology.  So instead, I’m now deleting that and taking a personal moment to show off my awesome new dog named Rocky.

 

Rocky

He’s a shelter rescue mutt, part welsh corgi and part pit bull they say.  If you’ve ever doubted the significance of genetics, just look at dogs.  They come in such a variety of sizes and shapes, and good portion of those moves have been intentional on the part of humans.  It’s a weird deal.  But I sure am glad to meet this guy.

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November 18th, 2013 at 11:16 pm

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Showing Exponential Growth in Bacteria

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So I got an interesting request from the math department at Sapling Learning about a week ago.  We wanted to show the concept of exponential growth, using bacteria as the example.  So one bacterium divides into two and they each divide into two and so on.  We decided to take this through six generations landing us with 64 bacteria on screen by the end of it.

So the catch was, how to move 64 bacteria around as one, and then as two with an equal number of divisions nested inside and then as 4, each with an equal number of divisions inside, and then as 8 and so on.  So I got a little complicated with my object hierarchy for this one.

screenshot object hierarchy

So I had one called cp_start, short for clostridium perfringens (a bacterium capable of reproducing at the 15 minute generation cycle that we wanted for the example) with a bend object on it.  And then nested within that one was a duplicate called cp_15, another called cp_30, cp_45, cp_60, cp_115, and cp130, to represent the ones that would branch divide off at the 15 minute, 30 minute, 45 minute, hour, hour 15, and hour thirty points from that one, all with their own bend objects.  Then within each of those I had further duplicates that would still occur from each of those.  Within cp_45 there was cp_60, cp_115, and cp_130, but cp_60 would only have cp_115 and cp_130.  And then so on with each bacterium.

In the end it worked out, and the extra arranging effort was well worth it as the sprawl pattern of bacteria had to be adjusted after the first time.  My first attempt had them all more compactly arranged, but one of our biology experts explained that bacteria could only continue a regular exponential growth cycle if they were able to get to more food.  If I hadn’t had them nested like this, it would have been incredibly hard to go back and make them disperse further.

bacterialgrowthprogression

I added the timer and count in After Effects.  The whole thing plays at a sped up pace, showing one minute per second of animation.  And I think it looks good.  I hope that we get to use it for biology content someday as well as for the math example now.

Written by Sara

September 30th, 2013 at 10:32 pm

DNA Replication – 3D Animation

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Hello again readers!  I’m so happy to be able to finally share with you all an animation that I worked on some months back for Sapling Learning.  Some of you will recall me writing about this one before.

The 3D models were created by studying the molecular sizes and shapes of the relevant molecules and then creating simplified representations. The 3D animation itself was created using Maxon’s Cinema 4D. Then the individual shots were composited together in Adobe’s After Effects. Audacity was used to record the narration, and then it was all put together for timing in Final Cut Pro (I still use an older version and cannot speak to all the changes they made in X.) I went back into After Effects for further labeling and effects (like the zoom into DNA polymerase) after that. So that’s the basic work flow.

There are a lot of biochemical processes that feel like a very complicated ballet as you get further into them.  Putting together the action of everything happening at the same time for the final shot in this animation really got me thinking about that analogy again.  And the truth is, that when this actually happens in nature, that lagging strand is actually being whipped around by helicase and read in an even more complicated fashion.  I really like that we emphasized that we were simplifying for clarity with this one.  A lot of educational materials would just let students find that out later if they went on to the next step in their studies.  That kind of thing always bothered me when I learned about such processes in school, and I’m happy to be with content experts who are willing to take the time to either make something more accurate, or let students know when things are being brushed over or left out of the picture for clarity.  I think that kind of thing is important.

Anyway, I’m really happy to be able to share this with you all.

Written by Sara

April 7th, 2013 at 9:03 pm

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