Converting Bezier controller handles to x,y offsets

[tbttfox]

The values for tangent handles seem really arbitrary.

The docs say that the values "Control the absolute velocity at a key using the In/Out values"

So I checked a linear key at (24,1) at 24 fps in generic units. That's 1 unit movement over 1 second. It seems logical that the tangent value would be 1.

But we get 0.005.  Why????  Is there some scale factor of 1/200 just built in?

[klvnk]

for mxs this is the code i use for a bezier xyz position controller, hope it helps

fn GetOutY key next =
(
    len = key.outTangentLength ;
    if key.constantvelocity then
        len = [0.33333333,0.33333333,0.33333333];
    key.value + key.outTangent * len * ((next.time - key.time) as float) / (framerate);
    
)

fn GetInY key prev =
(
    len = key.inTangentLength;
    if prev.constantvelocity then
        len = [0.33333333,0.33333333,0.33333333];
    key.value + key.inTangent * len * ((key.time - prev.time) as float ) / (framerate);
    
)

[tfoxTD]

That works perfectly well for getting the Y value of the tangent handles.
How about the X? That's where my problem lies.

[klvnk]

TangentLength (in or out) is always the proportion of the time between frames so x = TangentLength  * "numberofframesbetweenkeys"

from the mxs help....

.inTangentLength and .outTangentLength, (typically a fraction from 0 to 1) represent how long the handle is towards the adjacent key. For example, a value of 0.5 means the handle reaches halfway from the current key to the adjacent key, and a value of 1 reaches all the way. If the handle reaches beyond the adjacent key, it will be greater than one. If there is no previous key, the value of .inTangentLength will be -1.

[tfoxTD]

Oops, I apologize, you are correct.  The Y value was the problematic one. I was a bit distracted when I looked at that and got the values mixed in my head. Especially because that code was stupidly straightforward, I thought it was the X.

Thanks, it is exactly what I was looking for.