spine tracking speed over length

[Pierre]

spine tracking speed over length

Hi Martin,

I have noticed a given behavior of the spline tracking tag.

Instead of having a regular speed over the entire spline length, there is probably a regular angle speed over all tangents.

The consequence is that if you have sharp curves in your spline, the speed is no longer regular (in length) at all - accelerating in the curves.

Note : I am currently using Bezier Splines.

Was this a desired behavior ?

How could I easily get a constant speed in length ?

Will anything be changed/added regarding this in a shortly released beta ? (or do I need to do some creasy key-framing to adjust the position delta depending on the position on the spline ?)

Thanks

p*

PS: I am talking about the position. No confusion with the heading.

 

[Martin]

How could I easily get a constant speed in length ?

Hi,
I'm surprised to hear that since Cheetah3D uses a "constant speed on length" by default. It is actually the only available mode. OK as long as the "position" parameter of the spline tracking tag increases linearly.

Are you sure it is not just an optical illusion?

Bye,
Martin

 

[Pierre]

Well, fine.

Please open the attached file, check when the closed spline (originally a circle spline) is used as path with the spline tracking tag... and give a close look at the object animation when it's approaching small radius curves. Obviously you'll use a top view to have an unbiased observation.

You don't need any rendering considering the simple scene, the OpenGL preview is enough. Actually you may want to slow down the animation on your powerful machines ;-)

Maybe I'm very very tired ( ? )

Cheers

p*

PS: I may have some more to report on spline tracking, if you want to.

 

[fused]

Burn transform your spline path and see it that helps.

Andrew

 

[Pierre]

Thanks Andrew, that does the job.

Just curious, is that a normal behavior ? (what is the feature I could use behind this ?)

Thanks again,

p*