Hi,
I’ve got a question about the TCB method. I’m interested not only in using it for animating, but also in the mathematics behind it. I theoretical know how the parameters tension, continuity and bias works, because I’ve read about it. But I can’t find anything about the temporal tension parameter and the differences to the tension parameter. For me it sounds actually the same.
Can you tell me something about it?
According to the code, the curve is a hermite curve (TCB) mapped over a hermite time where the hermite time has its two tangents scaled down by the temporal tension.
See code at
github.com/synfig/synfig/blob/m … imated.cpp
Lines 297, 298
mutable hermite<Time,Time> first;
mutable hermite<value_type,Time> second;
first is the hermite for the time and second is the hermite for the value.
Later they are filled up with the corresponding values based on TCB for the value hermite:
Lines 422 to 635
and for the time hermite:
Lines 638 to 642
So modifying the temporal tension would change the final result of the curve too, because the time is not linear.
-G
I have just reread the doc ( wiki.synfig.org/wiki/TCB ) in order to translate it … and it seems to be not really explicit … and maybe false in some aspect.
in fact, seems that others parameters than temporal tension are inecfective in tcb settings… (according to the graph representation of the value in the time)
thanks … very explicit TCB example file ! … could i use it has a base to illustrate the TCB wiki page ?
Of course! You can improve it by creating the alternative version with every at -5 value. Notice that it is possible to change the values from -20 to +20 but in theory they have not limits.
Also print the curves for each case would be great too for the wiki.
-G