biomechanics of human movement

i don't know if anyone have an idea about how to simulate the biomechanics of human movement. i need to define a dummi, or at least the shoulder and the arm movement.

any help or idea?.

thanks,

Javi

Replies to This Discussion

Permalink Reply by Luis Fraguada on February 17, 2011 at 6:31am

You will want to check out Inverse Kinematics. Daniel Piker has been working on some grasshopper inverse kinematics for kuka robots. This is usually how the problem is solved in programs like Maya with Character Rigging systems.

Permalink Reply by Luis Fraguada on February 17, 2011 at 8:35am

Yes, 3DS Max has this of course. If you want to use it in GH you have to study the mechanics of it in order to make it happen. It is definitely possible in GH, as you have seen in the video by Daniel.

Permalink Reply by Daniel Piker on February 18, 2011 at 9:39am

That IK for robots I posted is specific to 6 axis arms, and I'm not sure how easily the techniques I used there could be adapted for something like a human with many more degrees of freedom. I will be posting the definition soon though, so you could take a look.

In computer games 'ragdolls' are often made from a network of springs or rods, with some angular constraints. This sort of thing should be possible in Kangaroo with a little care, and using springs with cutoffs to prevent limbs moving too far.

Though a different and quite effective way I found of achieving similar results is with mesh inflation. Simply internal pressure and springs for the edges can give surprisingly realistic results, if the mesh triangulation is tweaked a bit to give flexibility in the right places.

I'll post the files for this soon, just have to fix a minor bug with custom masses in the Kangaroo release first.

Permalink Reply by Luis Fraguada on February 18, 2011 at 9:55am

I was refering to IK in general as the means by which this is typically addressed in digital models.

Videos above have made my day.

Permalink Reply by Hrvoje Petrovic on February 18, 2011 at 12:05pm

Amazing videos!

Permalink Reply by David Rutten on February 18, 2011 at 12:18pm

That is hilarious. And oh so cool. Reminds me of slow-motion karate videos:

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Daniel Piker on February 19, 2011 at 1:41pm

Thanks!

I know what you mean about the slow-mo stuff.

Also kind of like this

Here's the definition if anyone wants to have a play with it.

There's an MD slider to control the position of the ball, so you can slide it around and knock the poor guy over.

Attachments:

Meshguy.3dm, 80 KB
Meshguy.ghx, 374 KB

Permalink Reply by Hrvoje Petrovic on February 17, 2011 at 8:05am

You can also try DAZ Studio, its free.

Permalink Reply by Carlos Pérez on February 17, 2011 at 8:54am

This was done with an early version of GH:

http://rhinocentre.blogspot.com/2008/03/explicit-history-plugin-for...

Permalink Reply by Danny Boyes on February 17, 2011 at 9:22am

Unless you install a very old version of Grasshopper you will not be able to open the WRM file.

Permalink Reply by David Rutten on February 17, 2011 at 10:25am

The file-format is wired deep into the Grasshopper core. I either had to keep supporting a badly designed file format and write a lot of extra code for every new object and every change to an existing object, or I could ditch the format (there was a grace period) and invest my efforts into writing useful new things.

I know it's über-annoying to lose a file format, but since this happened during early beta stage development I felt it was a sacrifice worth making.

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by taz on February 17, 2011 at 5:27pm