Cineversity

Right, so I have to make a quick little animation that demonstrates the function of bezier handles.  I figure it will be easy enough to make the shape with a cylinder and a couple of spheres, and I could always just keyframe out the animation of the shape, then follow with a PLA for the handles, but I would like a more elegant solution so that any requested changes are easier to implement.

This seems like a perfect task for XPresso, but sadly beyond simple set driven keys, and PBlurp stuff, I am largely at a loss with the sheer volume of options XPresso presents. 

So, my question essentially is twofold:  Am I correct in thinking that XPresso can do this?  And, if so, could I get a little help in figuring out the way to do it?

Thanks as always,
-Will

Hi Will,

Sorry not possible to my knowledge in XPresso and even a quick search in Python showed no results. But maybe one of the Python wizards has an idea.

The only vague idea that I have is to work for a visualization of that effect—-maybe—- with the Spline IK and set the handles there. then use the Joints, to recreate a spline via nulls and Tracer. I haven’t tested it, just thinking out loud, as I think it is a little bit too much, based on the idea that animating such thing manually would be sufficient, perhaps.

The only way that I would think is easily to do for a visualization: PoseMorph. PoseMorph if set to point allows Bezier based animations. As you get with the storage of the “poses” a slider function, the connections to a Bezier Object (the representation of the handles) could find here it’s connection. The object could be set to the Spline knot/point following the tangention, and via “Set drive Set driven” Expression, you might find an option to set the length for your visualization. I stress here the point visualization as it introduces the idea that things must look right , but no need for a production ready solution, which should function for a longer period.

All the best

Sassi

How many bezier knots do you need?

AFAIK, there is no way to access the actual tangent handles.

I do have an idea that could work if you only need a couple knots.

You could easily hack together a few knots by using spline IK.

edit: lol. Sassi beat me to it
You can access the handle information through python…but it is stupid hard especially if you just need a few knots.

Hey Patrick, thanks!
Especially for the Python info.
Have a good one
Sassi

Hey guys,

  Thanks both for your responses.  I really only need one point on a spline, which I will first show with linear interpolation, and then in soft (bezier) interpolation.  I’ll then need to move the bezier handles around and have the swept spline path follow suit.  It’s just to illustrate anchor points vs control handles in Adobe Illustrator. 

  This is one of those situations where the solution seems like it may be more complex than the problem.  Perhaps I’ll just do it old school

Cheers,
- Will

Hey Will,

The concept could be simpler, just screen capture the two apps and if you like to get it more visually, track the points in Ae and overlay it with a graphic.

I can’t resist, the simplest way, if math is your friend, is to use the Bezier calculation to created it ;o) http://en.wikipedia.org/wiki/Bézier_curve  OK, just kidding. :o)

All the best

Sassi

Here is a quick example using spline IK.

Thanks for the example, Patrick.  It took me a second to figure out what you’d done, as I was having trouble moving the tangents, but then I saw you had them limited to horizontal movement.  For this particular piece, I had to show the way the path curves when one pulls the control handle up or down in Illustrator.  Ultimately, since it was a simple concept, I just did it with PLA.

Cheers!
- Will