[Nicolas Guionnet]

Thanks Steve,

… I replaced this expression by a simple :
time*time*100
… which gives a very funny accelerating effect … and the blur is back.

So I guess we can conclude that it is the expression’s fault …

[Nicolas Guionnet]

Hi Oleg,
Thanks for your answer.

Cross-referencing ? i am not sure that I understand what you mean. (circular definition ?)

I move the blue gear with the code below that controls its rotation … (but before you read it) … I just changed it to a basic time*1000 … and motion blur is back.

So it seems that here lies my problem :

t= time ;
t0 = 0 ;
t1 = 14 ;
pasT = thisComp.frameDuration/1 ;
SpeedCoef = 5 ;

// rotation speed or derivative
function speed(tt) { v = -SpeedCoef*(tt-t0)*(tt-t1) ; return v ; }

// speed integration to get rotation
alpha = 0 ;
for (var i = t0; i <= t ; i = i + pasT) {
alpha = alpha + speed(i)*pasT;
}
alpha

In fact it is just an innocent way to control the speed of the rotation.
It is strange that it kills motion blur. … and another details, it is not smooth … there is a step from time to time …

[Nicolas Guionnet]

This might help :

[Nicolas Guionnet]

Hi Kalleheikki ! … and thanks !

Yes that’s a good solution, I think. In fact I posted on another forum the question about the legitimacy of my former recursive approach. The answer was “no way” …
I took a great deal of time to think of a workaround … and I came to the same idea as you ! Local Average smooths out a function.
As I read your lines I understand that we could even circumvent a flaw of the recursive method : It’s late ! The first order filter never reaches the position of its target … it’s late.

(If I am not wrong — again …) With the average method, we could select the values of the target position in a neighborhood ot t … not necessarily the values before. We could apply a set of Gaussian curve coefficient around t … (And yes, with the recursive method you can’t access the future.)
The video is a loop so the algorithm could also see time as a loop so tMax + 1 = 0

I am so excited to try this ! I used to do math for the sake of math … but doing math for visual results is really fun … ☺

Thanks !

[Nicolas Guionnet]

It seems that it is not possible to use the previous position of an Object to calculate its new position.
The following expression does not work … The NULL should move. (it is in the NULL.position)

I guess this sort of recursive code is not allowed …
Any idea ?

newPosition = [] ;
if (time>0) {
lastPosition = thisComp.layer("NULL").position.valueAtTime(time-thisComp.frameDuration);
// filter core :
newPosition[0] = lastPosition[0] + 10 ;
newPosition[1] = lastPosition[1] ;
newPosition[2] = lastPosition[2] ;
}
else {newPosition = [960,540,0] ;}

[newPosition[0],newPosition[1],newPosition[2] ]

[Nicolas Guionnet]

A DEBUG INSANITY …
… well, I have been trying to solve this for a few hours. What I see is beyond my (poor) understanding of AE.
I wrote my expression using this simple filtering algorithm :
newPositionB = previousPositionB + 0.2*(positionA – previousPositionB)
This way B follows A (more) smoothly.

The result I get is almost satisfying, visually. But I checked the value : there is a little error.
So I pasted my expression in a text layer to debug … and this is crazy :
The values calculated in the debug text are right … but they are not applied to B’s position.

Debug text gives me for instance newPosition[0] = 977 but B is at 968 …

Moreover, in B’s expression, I tested all the intermediary variables (lastPosition, targetPosition ) by affecting them to the first coordinate … and it is consistent with the debug text. ONLY, newPosition … which is calculated from the others remains erroneous …

So I really don’t understand …

Does any body have an idea ? … to save my soul before it blows out.
Thanks !

// expression for B's position
targetPosition = thisComp.layer("NULL--All-In-A-Frame").transform.position.value;
smoothCoeff = thisComp.layer("Curseurs---->").effect("smoothCoeff")("Slider").value/100 ;
newPosition = [0,0,0] ;
if (time>0) {
lastPosition = thisComp.layer("NULL-filtered").position.valueAtTime(time-thisComp.frameDuration);
// filter core :
newPosition[0] = lastPosition[0] + smoothCoeff*(targetPosition[0] - lastPosition[0]) ;
newPosition[1] = lastPosition[1] + smoothCoeff*(targetPosition[1] - lastPosition[1]) ;
newPosition[2] = lastPosition[2] + smoothCoeff*(targetPosition[2] - lastPosition[2]) ;
}
else {newPosition = targetPosition.slice() ;}
[newPosition[0],newPosition[1] ,newPosition[2] ]

--------------------------------------------------------------------------------------
// Expression for debug text
targetPosition = thisComp.layer("NULL--All-In-A-Frame").transform.position.value;
smoothCoeff = thisComp.layer("Curseurs---->").effect("smoothCoeff")("Slider").value/100 ;
newPosition = [0,0,0] ;

if (time>0) {
lastPosition = thisComp.layer("NULL-filtered").position.valueAtTime(time-thisComp.frameDuration);
// filter core :
newPosition[0] = lastPosition[0] + smoothCoeff*(targetPosition[0] - lastPosition[0]) ;
newPosition[1] = lastPosition[1] + smoothCoeff*(targetPosition[1] - lastPosition[1]) ;
newPosition[2] = lastPosition[2] + smoothCoeff*(targetPosition[2] - lastPosition[2]) ;
}
else {newPosition = targetPosition.slice() ;}

"last Position = " + lastPosition + "\n targetPosition = " + targetPosition + "\n newPosition = " + newPosition

[Nicolas Guionnet]

Thanks for your help Oleg !

Converting animation to keyframes, copying it and smoothing the movement through spatial interpolation … is a possible solution but I have to do it every time the animation of NULL1 is changed … and it depends on the behavior of a lot of objects that may change often according to my needs.
So I need it to be automatic.

I think I will go for the second option. I will write the filtering expression soon and publish it here (I might not be the only beginner who needs this …)

Thanks !

[Nicolas Guionnet]

Hi Michael !
Thanks ! Good idea. It will look like the radiator of my CPU if I enable shadow on the copies ( but I won’t ! )
Without shadow and with a sufficient number of copies, this trick should work well !

[Nicolas Guionnet]

Tanks Dave, Thanks Max, (order of appearance ☺ )
… mmm … it seems tough for a two weeks old baby like me (in AE) … and tuning it would probably be very time consuming. For the more subtle is the idea, the more efforts needed to find the good parameters to make it work … ☺

I wonder if the time needed for me to learn all this is not longer than the time needed for Adobe to provide us with a new version of AE with extrude and DOF in the same 3D renderer.

I am not the only one hoping for this I guess … DOF gives so much realism and even charm to a scene …

Well I made my choice for the moment and will use Classic 3D for the sake of DOF (in a couple of clicks). There may be a way to approach the effect of extruded shapes …

[Nicolas Guionnet]

Thanks Dave,
I meant that I needed to extrude simple 2d shapes and then give them some shadow and add depth of field.
And there is no way to extrude shapes in Classic 3d (that I know of).
And there is no DOF in C4D.
… I must admit that this is not what I asked. I appreciate your tact. ????