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(Seamlessly) Loop Array Object function (Frequency of Array)

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Peter Shawn
(Seamlessly) Loop Array Object function (Frequency of Array)
on Dec 3, 2011 at 11:31:48 am

Hey!

I was wondering how it is possible to create a loop with the frequency of the array object. I tried everything but somehow it is calculated strangely... or my math ist just that bad (it actually is).

So when I set the frequency to 10 and the array frequency to ... wait hm, I actually don't really get it even less after reading the help file to the array object.

From the help file:

Frequency [0..+∞]
Use this setting to determine the rotational wave velocity.
Array Frequency [0..+∞]
The Array Frequency defines the number of waves.

Anyways... when I set both to 2 ... it's not seamless on a 100 frames timeline with 25fps (do the fps play in there?)

Ok now this is what I found out, with the values 2 for array frequency and normal frequency the perfect loop point is after 95 frames. Can anybody explain this to me? And maybe how I can calculate my loops in future?

Cheers!


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Brian Jones
Re: (Seamlessly) Loop Array Object function (Frequency of Array)
on Dec 4, 2011 at 6:13:58 pm

Array Frequency and the number of copies control the shape. If you want to loop the motion then Frequency alone matters. You can use this formula
Frequency = Desired Number of Cycles*(FramesPerSecond/Number Of Frames To loop Over)*2*Pi

That applies to each of the copies in the Array, if you watch any one of them it will cycle in place up and down as many times as you have set. So if I want 3 cycles over 167 frames and my project is at 30 fps (for me anyway, for you it would be 25) I enter 3*30/167*2*pi

So for you I'm guessing a 100 frame timeline means you really have 101 frames (because you are using frame 0 too) and your fps is 25 so it's Number Of Cycles*25/101*2*pi

Just in case you don't know C4D knows that "pi" is 3.14159(etc) so you just have to enter it like I have put it here and C4D does the math for you.


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Peter Shawn
Re: (Seamlessly) Loop Array Object function (Frequency of Array)
on Dec 4, 2011 at 9:54:45 pm

Thanks for your answer - but I guess I have plenty to learn. I am well aware of the fact how to loop certain parameters over time - I know this formular from after effects - but in this case I absolutely don't understand how I could use this formular correctly - my parameters look like this:

http://imgur.com/bGxlu

If I wanted to animate the array manually, I'd use your formular - but in this case, if I understand it correctly, that dialog with all the parameters is there to 'make the math' for me, right? ...anyways I am a bit confused now :P Maybe you could point me into the right direction =)

Cheers!


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Brian Jones
Re: (Seamlessly) Loop Array Object function (Frequency of Array)
on Dec 5, 2011 at 1:22:23 am

How many frames do you want the loop to happen over?


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Peter Shawn
Re: (Seamlessly) Loop Array Object function (Frequency of Array)
on Dec 5, 2011 at 1:26:27 am

128 (so from 0 to 127)


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Brian Jones
Re: (Seamlessly) Loop Array Object function (Frequency of Array)
on Dec 5, 2011 at 3:54:36 am

oh sorry, and how many waves do you want each particle to go through in that 128 frames? I ask because in the example pic the values set make each object go through approximately 6 and a half cycles but since the Frequency is set a 10 so I thought you might be aiming for 10...


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Peter Shawn
Re: (Seamlessly) Loop Array Object function (Frequency of Array)
on Dec 5, 2011 at 7:47:54 am

Well, I want to understand it ;) So it doesn't matter... I just want all objects to be in the same position on frame 127 as in frame 0 - in this case I thought 10 full sine waves, yes...


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Peter Shawn
Re: (Seamlessly) Loop Array Object function (Frequency of Array)
on Dec 5, 2011 at 12:03:46 pm

I'd like to understand all that parameters actually.

Actually I changed some parameters in my scene to make it easier:

FPS: 32, Frames: 128, so that 4 waves * 32 = 128; so any amount of waves that can be divided by 4 are good.

Can you explain to me what the array function is? I still don't get the point somehow... how would I achieve 4 waves (a wave is a full sine wave, right? (=2*PI))


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Brian Jones
Re: (Seamlessly) Loop Array Object function (Frequency of Array)
on Dec 6, 2011 at 4:26:44 am

to get 4 waves in the shape of your array just set Array Frequency to 4.

put a radius 20 sphere in an Array
- radius - leave it at 250
- copies - 180
- amplitude - 80
- Frequency - 0
- Array Frequency - 0

now adjust Array Frequency upwards, as you adjust Array Frequency upwards still waves form. Anytime Array Frequency is a whole number there are that number of complete waves in the shape. So if you want 4 waves set Array Frequency to 4.
Frequency controls the apparent movement of those waves around the circle over time, hit the play button to start playing through the frames, increase Frequency and let it go - the waves now "move" around circle. The waves 'jump' when the playhead loops back to frame zero - unless you have the right speed of movement (the right Frequency) - so if you want that to be a clean loop you have to use that formula from earlier - Frequency = desired number wavelengths moved * (fps/frames) * 2 * pi.

So for the array above with 4 waves
- radius - 250
- copies - 180
- amplitude - 80
- Frequency - 0
- Array Frequency - 4

if you want the waves to move two wavelengths over the length of the timeline (for my example I'm thinking of the default NTSC 30fps and 91 frames in the timeline) you enter 2*30/91*2*pi into the Frequency box and hit return and let it calculate...

If I'm being totally obvious sorry, I guess I don't understand what you are not understanding.


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Peter Shawn
Re: (Seamlessly) Loop Array Object function (Frequency of Array)
on Dec 9, 2011 at 10:58:07 am

Hey Brian,

thanks a lot for your patience but I think I don't achieve a loop - even with your detailed instruction.

So this is with those parameters:

So for the array above with 4 waves
- radius - 250
- copies - 180
- amplitude - 80
- Frequency - 0
- Array Frequency - 4

http://i.imgur.com/rciYN.png
http://i.imgur.com/Z4bTo.png

And this is with the formular (for Frequency: 4*(32/128)*2*pi, same for array frequency ...

http://i.imgur.com/fchcg.png
http://i.imgur.com/M364z.png

Maybe you now see my problem. I see my problem but I still don't see the solution unfortunately :(

Cheers!


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Brian Jones
Re: (Seamlessly) Loop Array Object function (Frequency of Array)
on Dec 10, 2011 at 3:50:55 am

Array Frequency determines the array's shape, in your second two pictures Array Frequency is set to 6.333 - the shape will only connect seamlessly if it's a whole number like in the first two images (4). Set Array Frequency to 6 or 7 (or whatever), if you want it to be seamless it has to be a whole number it can't be a fractional number like 6.333.


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Peter Shawn
Re: (Seamlessly) Loop Array Object function (Frequency of Array)
on Dec 15, 2011 at 10:33:34 am

That's what I did after your recipe when I may quote you:

"if you want the waves to move two wavelengths over the length of the timeline (for my example I'm thinking of the default NTSC 30fps and 91 frames in the timeline) you enter 2*30/91*2*pi into the Frequency box and hit return and let it calculate..."

That's what I did there.

I still don't really get it. Seems to be too complicated thought either of me or the devs.


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