Blender 2.5: mocap friendly tools?

General Forums Blender and CG Discussions
1

Hi,
Blender is not very friendly in mocap application. Anybody noticed this? http://www.alienhelpdesk.com/technobabble/mocap_in_blender .

These tools mentioned by him are very indispensable for mocap based animation workflow. Any idea of implementing in upcoming 2.5 release?

2

Perhaps something for the next open project from the Blender Institute. Project Mango I believe. It’s not on the Durian wish list. So this will take some time

3

A lot is being changed in 2.5 in regards to the animation system already, I haven’t really looked at using mocap data in there yet, but it may well be that most issues have been dealt with.

It’s certainly something that would benefit from some attention from the coders, but I don’t think it’s on the list of priorities right now.

4

Blender 2.5 has introduced the concept of modifiers for F-curves, which is even better than what that proposal suggests. There’s actually already an envelope modifier for modifying complex animation data. It’s cool, but unfortunately pretty hard to use in practice because you have to dial all values in manually, making it pretty slow.

It’d be nice to simply be able to draw (or ctrl-click) a new simple curve and make that drive the complex mocap curve underneath. XSI has had this for a while and it’s great.

A smooth modifier would be fantastic, as would a simplify modifier that would approximate a complex curve using fewer points.

The other points regarding action influences and actions in general have been addressed already in 2.5, though some details in the new system still need some love. The foundation is there for a much better system, but working with actions has some workflow issues hat would be nice to work out.

5

you are right William…

Re-targeting of armatures is also very needed. Simply importing an bvh does nothing if the targeted character is not the same proportion as the imported bvh armatures.

6

For those who don’t know what retargeting is …
Here’s the demo of motion builder…

Motion capture retargetting paper:

Outline of Retargetting Algorithm
Step 1:
Begin with an initial motion with identified constraints.
These constraints can either come from:

  • restrictions on the character, such as elbows do not bend backwards. the environment, such as nothing should be below the floor.
    the motion, such as the character must pick up the box in frame 30.

Note: In this technique, they only dealt with equality constraints.Step 2:Find an initial estimate m1(t) of the solution.

  • scale translational parameters. add translation to define the center of scaling.

Step 3: Choose a representation for the motion-displacement curve.

  • represent the motion-displacement as cubic B-splines with uniformly spaced control points.

Step 4:

  • Solve the non-linear constraint problem for a displacement that when added to step(2) provides motion that satisfies the constraints.

Final Form of the equation:
minimize 0.5 * xT * x subject to f(x) = C,
where f is a function of x, the control points, and
C is a column vector of size equal to the total number of constraints.Solve the above equation iteratively using a Sequential Quadratic Programming (SQP) solver.

http://davis.wpi.edu/~matt/courses/retarget/

Hope somebody with enough programming knowledge would take the initiative…,

7

We really need this in my line of work. Is there any way to turn this into an official proposal?

8

Thanks mohanhi for pointing this examples out.
This is, of course a splandid control solution!
But gee… Personnaly, i’d have to reach quite a skill with bones before even thinking of being abble to use such tools! :o