Anatomy and Art

a blog by Sara Egner

Animating DNA

with 2 comments

I’ve been doing some work to get started on a new animation at work lately.  This one is about DNA replication, and some of the animation needed to tell the story is making for some interesting challenges.  Now, if you just want to model some DNA within Cinema 4D, this is hands down, the best tutorial I have seen for that.

http://www.bmc.med.utoronto.ca/bmcwiki/doku.php/technologies:cinema_4d_tutorial_-_schematic_dna_1

There’s a part 2 to that too, so do keep going if you get into the first one.

The trouble with this model though, is that you can’t unzip the DNA to show how replication works.  So I’ve been trying some alternate methods lately.  At first, I was very excited about getting the backbones to open up like this.

But I still couldn’t get the bases to work with me.  That version was utilizing the helix shaped splines and sweep nurbs set at 130º.  And the spherify deformer could be animated to open the double helix according to keyframes.

One of the tricks with trying to do this is that you can’t apply your deformers to the double helix at large without mangling your model.  You do a lot better to apply them directly to your splines and set up your bases as cloners to those splines, and your backbone as sweep nurbs along those same splines, so that the individual strands maintain their shape.

I also learned, that it’s much easier to line up your bases if you start with a straight ladder sort of arrangement, and then apply twist deformers to a null object containing the double helix so that they stay together.  You can then animate your deformers along the strand to wind and unwind your DNA, and with the addition of an FFD deformer along each spline, you can then animate the stream opening as you unwind it.  And the big trick, that you might not think of with that – uncheck the align clone option in your cloner.  For hours and hours, everything I did sent my bases all over the place, until I finally tried unchecking that box, and then they stayed align.  I could go on about that for a while, but the important thing is to mention it so we all know not to get stuck like that in the future.  Honestly, now that I’m thinking about it, some of my earlier attempts may have actually worked out, had I tried unchecking that box sooner.

And of course, being a big crazy 3D program, there are absolutely other ways of getting at a solution.  In looking for ideas with this one, I wound up using the AMI listserve’s professional groups, and came across an animator in Germany named Andrej Piatkowski who found a way to do this without using splines at all.  He felt like they just got in the way, and as you can see, he got some really cool results with what he did.

He doesn’t have it connected on the other side, the way I’m wanting for my purposes, but I love how neatly everything fits together and then rips apart so smoothly.

So remember, in your own efforts, there are many paths to the solutions you seek.  But hopefully something here can help you out a little if you’re doing similar work.

Written by Sara

December 2nd, 2012 at 8:23 pm

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2 Responses to 'Animating DNA'

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  1. Pretty! This has been a really wonderful post. Thank you for providing these details.

    Etha Weber

    28 Jul 14 at 4:54 pm

  2. Thankyou for helping out, excellent info .

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