Time Loop Layer

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The Time Loop layer can be used to repeat an animation over and over.
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<!-- Page info -->
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{{Title|Time Loop Layer}}
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{{Category|Layers}}
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{{Category|Time}}
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<!-- Page info end -->
  
It has 2 parameters, Start Time and End Time. These parameters, like any other in Synfig can be animated, so that they change over time.  This can be confusing, so make sure you aren't in Animate Edit Mode when working with the Time Loop layer, unless you know what you're doing!
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{{l|Image:Layer_other_timeloop_icon.png|64px}}
  
If the Start Time is later than the End Time, then the Time Loop Layer doesn't do anything, it acts as if it wasn't there.
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== About Time Loop Layers==
  
Otherwise, the Time Loop layer makes time stand still until Start Time, and then to repeatedly loop through the first (End Time - Start Time) seconds of its child layers.
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The {{literal|Time Loop layer}} is used to repeat an animation over and over. It loops a section of the layers below and within the same canvas over and over.
  
For example, suppose Start Time is 5s and End Time is 8s, and that the Time Loop layer is applied over an existing animation.  For the first 5 seconds, the Time Loop layer will stand still, as if the time was 0s (or less) throughout.  From 5s to 8s, the first 3 seconds of the child layer will play.  Then from 8s to 11s, and from 11s to 14s, etc, those first 3 seconds of the child layer will play over and over again.
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See also the {{l|Convert#Time_Loop|Time Loop ValueNode}} conversion, which can be used to loop the value of a single parameter, rather than an entire layer or group of layers.
  
: Note - what actually happens is that for the first 5 seconds, time loops through negative times in the child layer, but since it is impossible (?) to animate anything at negative time points, this should be the same as the time staying at zero. It's not clear whether this is a bug, or whether any existing animations rely on this behaviour.  This is how the mapping actually works:
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==Parameters of Time Loop Layers==
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These parameters, to '''prevent undesired modification''', by default are {{l|Static_Parameters|statics}}.
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The parameters of the time loop layers are:
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{|border="0" align="none" style="border-collapse"  cellpadding="3" cellspacing="0"
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|-style="background:silver"
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|'''Name'''||'''Value'''||'''Type''' 
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|-style="background:#"
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||{{l|Image:Type_real_icon.png|16px}} {{l|Z Depth Parameter|Z Depth}}
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||0.000000
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||real
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|-style="background:#eeeeee"
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||{{l|Image:Type_time_icon.png|16px}} {{l|Time_Loop_Layer#Link_Time_.28time.29|Link Time}}
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||0f
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||time
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|-style="background:#"
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||{{l|Image:Type_time_icon.png|16px}} {{l|Time_Loop_Layer#Local_Time_.28time.29|Local Time}}
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||0f
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||time
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|-style="background:#eeeeee"
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||{{l|Image:Type_time_icon.png|16px}} {{l|Time_Loop_Layer#Duration_.28time.29|Duration}}
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||1s
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||time
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|-style="background:#"
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||{{l|Image:Type_bool_icon.png|16px}} {{l|Time_Loop_Layer#Only_For_Positive_Duration_.28bool.29|Only For Positive Duration}}
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||
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{| style="width:16px; height:16px" border="1"
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|-
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|}
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||bool
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|-style="background:#eeeeee"
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||{{l|Image:Type_bool_icon.png|16px}} {{l|Time_Loop_Layer#Symmetrical_.28bool.29|Symmetrical}}
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||
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{| style="width:16px; height:16px" border="1"
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|-
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|}
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||bool
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|}
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=== Link Time (time) ===
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Start time of cycled material/child layers.
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=== Local Time (time) ===
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Start time of loop. (this is currently (since 120323 at least) ''broken'' and has no effect on time loops, see http://synfig.org/forums/viewtopic.php?f=12&t=3526#p14986 for a discussion)
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=== Duration (time) ===
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Number of seconds or frames that are looped in the child layer.
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=== Only For Positive Duration (bool) ===
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* If checked and {{Literal|Duration}} is zero or negative, then the time loop layer is effectively disabled, and acts as if it wasn't there.
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* If not checked and the Duration is zero, the Time Loop layer freezes the animation of the children layers at the value of {{Literal|Link Time}}.
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=== Symmetrical (bool) ===
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If not checked, and the current time is less than {{Literal|Local Time}}, then {{Literal|Duration}} is taken off the resulting time.  This is to provide compatibility with {{l|Time Loop Layer (v0.1)|version 0.1}} of the time loop layer.
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== How to use the Time Loop Layer ? ==
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The {{literal|Time Loop layer}} repeatedly loops through the {{Literal|Duration}} seconds of its child layers, from {{Literal|Link Time}} to {{Literal|Link Time}} + {{Literal|Duration}}.
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{{Literal|Local Time}} is used to line up the offset of the time looping.
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When the Time Loop layer is asked to set its time to {{Literal|Local Time}}, it sets the time in its child layers to be {{Literal|Link Time}}, ie. the start of the loop.
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=== Breaking loop ===
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# Be Sure you are not in {{l|Animate Editing Mode|Animation Mode}}
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# In the layer's parameters of the time loop, you need to remove the 'green guy' ({{l|Image:Animate mode off icon.png|16px}}), indicating that the parameter is {{literal|Static}}, from {{l|Time_Loop_Layer#Duration_.28time.29|Duration Parameter}}. Just right-click on him and set {{literal|Allow animation}}. See {{l|Static Parameters}} for more informations.
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# On the {{L|Timebar|timeline}} navigate to a place where you want to break the animation. And now enter the {{l|Animate Editing Mode|Animation Mode}}.
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# In the time loop parameters, set 'Duration' to {{literal|EOT}} (End-of-Time).
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# Now you have three {{l|Waypoint|waypoints}}. One before the current, we left it as it is. One is current, we {{l|Convert|convert}} it to the {{literal|constant}} (right-click on it -> Both -> Constant). And one after current, this one have to be removed (right-click on it -> Remove).
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# Now test it. Pay attention, that loop will always break at the very first frame of you animation, so you need to break it in the right place.
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===Detailed explanation===
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'Green guy' ({{l|Image:Animate mode off icon.png|16px}}) - {{l|Static Parameters}} - is a guard that says "You shall not pass!" to the animation. So when you attempt to change such parameter in animation mode it just changes the usual way. It's done to prevent unnecessary parameters to be animated, e.g. {{l|Blend Method Parameter|Blend Method}}.
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Setting {{Literal|Duration}} to {{literal|EOT}}. If you set it to 0f, then the whole animation will stop, because you try to play it from 0f ({{Literal|local time}}) to 0f ({{Literal|Duration}}). And EOT means it'll continue to play your animation to the end of the time...
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Removing {{l|Waypoint|waypoint}} after current one. If you skip this step, then at the next waypoint {{Literal|Duration}} parameter will be restored to the value before current waypoint. It's a standard Synfig's behavior, but there's a magical button somewhere that can change it.
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Converting current waypoint to the constant. Without it, {{Literal|Duration}} will be smoothly interpolated from value you set to the EOT and the constant type will just set immediately at the waypoint. Interpolation can be a bit confusing sometimes, so you better read this about {{l|Waypoint|waypoints}}.
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<!--
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To break a loop and continue animating you basically need to do two things; break the loop with a {{L|Waypoint|waypoint}} and copy the animation {{L|Keyframe|keyframe}} to your position in the {{L|Timebar|timeline}}.
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* Find out which frame in the child layers that corresponds to the frame in the time loop layer where you want to break the loop.
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Goto this frame in the child layer and add a {{L|Keyframe|keyframe}} here. Then goto the frame where you want to break the loop and duplicate the keyframe.
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* Set the first time loop {{Literal|Duration}} waypoint to {{Literal|Constant}} and check {{Literal|Only For Positive Duration}}. Then at the breaking frame set {{Literal|Duration}} to 0.
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* Continue animating the child layer(s) which are not looped anymore.
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-->
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== Visualized Example ==
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For example, suppose:
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* Link Time is 5s
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* Duration is 3s
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* Local Time' is 4s
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And suppose that the Time Loop layer is applied over an existing animation.  The {{Literal|Link Time}} and {{Literal|Duration}} specify that the section from 5s to 8s in the children layers will be looped.  The {{Literal|Local Time}} specifies that this loop will be at the beginning at 4s(And so also therefore at 1s, 7s, 10s, etc).
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This is how the mapping actually works:
  
 
{| border="1" cellspacing="0"
 
{| border="1" cellspacing="0"
|'''real time'''||'''child time'''
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|'''real time'''||'''child time<br/>(symmetrical = true)'''||'''child time<br/>(symmetrical = false)'''
 
|-
 
|-
| 0 || -2
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| 0 || 7 || 4
 
|-
 
|-
| 1 || -1
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| 1 || 5 || 2
 
|-
 
|-
| 2 || 0
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| 2 || 6 || 3
 
|-
 
|-
| 3 || -2
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| 3 || 7 || 4
 
|-
 
|-
| 4 || -1
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| 4 || 5 || 5 (local time = 4; link time = 5)
 
|-
 
|-
| 5 || 0
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| 5 || 6 || 6
 
|-
 
|-
| 6 || 1
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| 6 || 7 || 7
 
|-
 
|-
| 7 || 2
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| 7 || 5 || 5 (duration = 3, so loop repeats after 3 seconds)
 
|-
 
|-
| 8 || 0
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| 8 || 6 || 6
 
|-
 
|-
| 9 || 1
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| 9 || 7 || 7
 
|-
 
|-
| 10 || 2
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| 10 || 5 || 5
|-
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| 11 || 0
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|-
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| 12 || 1
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|-
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| 13 || 2
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|-
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| 14 || 0
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|-
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| 15 || 1
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|-
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| 16 || 2
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|}
 
|}
  
Specifying a huge number for the End Time parameter effectively turns the Time Loop layer into a Time Shift layer.  The Start Time parameter controls the amount of the timeshift, with both positive and negative values working as expected.
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Specifying a huge number for the Duration parameter effectively turns the Time Loop layer into a Time Shift layer.  The Link Time and Local Time parameters controls which time in the children lines up with which time in the Time Loop layer, giving the amount of the timeshift, with both positive and negative differences working as expected.
  
 
== Contrived Example ==
 
== Contrived Example ==
  
Download and examine this example file: [[Media:Time-loop-demo.sifz|Time-loop-demo.sifz]]
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Download and examine this example file: {{l|Media:Time-loop-demo-0.2.sifz|Time-loop-demo-0.2.sifz}}
 
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[[Image:Time-loop-demo.png]]
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It's a 10 second animation, and shows 2 circles.  The top one moves linearly from the left to the right.  Its position is marked by static text digits 0 through 10.
 
It's a 10 second animation, and shows 2 circles.  The top one moves linearly from the left to the right.  Its position is marked by static text digits 0 through 10.
  
The other circle is an identical copy of the first one, with the same waypoints, but it's inside an encapsulation layer with a [[Time Offset Parameter|Time Offset]] of 2s.
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The other circle is an identical copy of the first one, with the same waypoints, but it's inside an Group layer.  The parameters are:
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* Link Time: 5s
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* Duration: 1.5s
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* Local Time: 2s
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* Symmetrical: true
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So as time=2s, the top circle is at position 2 (local time) and the bottom circle is at position 5 (link time):
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{{l|Image:Time-loop-demo-0.2-2s-0f.png}}
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The loop is 1.5s long, so the bottom circle is also at position 5 every 1.5 seconds before and after this point in time, for example at t=3.5s and at t=8s:
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{{l|Image:Time-loop-demo-0.2-3s-12f.png}}
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{{l|Image:Time-loop-demo-0.2-8s-0f.png}}
  
The "Time Offset" encapsulation layer is Time Looped, with a Start Time of 5s and an End Time of 6.5s.  The Time Offset makes it possible to see how the Time Loop layer sets the time to be negative before Start Time is reached.
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The following two images show the positions at t=0s and t=3s.  The loop starts at t=2s, so it's also at the start at t=0.5s.  So at t=0s it's half a second before finishing the previous loop.  And at t=3s the same is true, but 2 loops later on:
  
For the first 5 seconds, the Time Loop will be outputting times between -1.5s and 0s, and for the last 5 seconds it will be outputting times between 0s and 1.5s. The Time Offset of 2s will shift these outputs forward by 2s, so before 5s the circle will appear between 0.5 and 2, and after 5s the circle will appear between 2 and 3.5.
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{{l|Image:Time-loop-demo-0.2-0s-0f.png}}
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{{l|Image:Time-loop-demo-0.2-3s-0f.png}}
  
There's a rendered copy of this example on [http://www.youtube.com/watch?v=qZlpPKyucRk YouTube], and it's also available for download: [[Media:Time-loop-demo.avi|Time-loop-demo.avi]]
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There's a rendered copy of this example on [http://www.youtube.com/watch?v=WyYLd7319Gw YouTube], and it's also available for download: {{l|Media:Time-loop-demo-0.2.avi‎|Time-loop-demo-0.2.avi‎}}.

Revision as of 12:59, 26 February 2017

Languages Language: 

English


Layer other timeloop icon.png

About Time Loop Layers

The "Time Loop layer" is used to repeat an animation over and over. It loops a section of the layers below and within the same canvas over and over.

See also the Time Loop ValueNode conversion, which can be used to loop the value of a single parameter, rather than an entire layer or group of layers.

Parameters of Time Loop Layers

These parameters, to prevent undesired modification, by default are statics.

The parameters of the time loop layers are:

Name Value Type
Type real icon.png Z Depth 0.000000 real
Type time icon.png Link Time 0f time
Type time icon.png Local Time 0f time
Type time icon.png Duration 1s time
Type bool icon.png Only For Positive Duration
bool
Type bool icon.png Symmetrical
bool

Link Time (time)

Start time of cycled material/child layers.

Local Time (time)

Start time of loop. (this is currently (since 120323 at least) broken and has no effect on time loops, see http://synfig.org/forums/viewtopic.php?f=12&t=3526#p14986 for a discussion)

Duration (time)

Number of seconds or frames that are looped in the child layer.

Only For Positive Duration (bool)

  • If checked and "Duration" is zero or negative, then the time loop layer is effectively disabled, and acts as if it wasn't there.
  • If not checked and the Duration is zero, the Time Loop layer freezes the animation of the children layers at the value of "Link Time".

Symmetrical (bool)

If not checked, and the current time is less than "Local Time", then "Duration" is taken off the resulting time. This is to provide compatibility with version 0.1 of the time loop layer.

How to use the Time Loop Layer ?

The "Time Loop layer" repeatedly loops through the "Duration" seconds of its child layers, from "Link Time" to "Link Time" + "Duration".

"Local Time" is used to line up the offset of the time looping.

When the Time Loop layer is asked to set its time to "Local Time", it sets the time in its child layers to be "Link Time", ie. the start of the loop.

Breaking loop

  1.  Be Sure you are not in Animation Mode
  2. In the layer's parameters of the time loop, you need to remove the 'green guy' (Animate mode off icon.png), indicating that the parameter is "Static", from Duration Parameter. Just right-click on him and set "Allow animation". See Static Parameters for more informations.
  3. On the timeline navigate to a place where you want to break the animation. And now enter the Animation Mode.
  4. In the time loop parameters, set 'Duration' to "EOT" (End-of-Time).
  5. Now you have three waypoints. One before the current, we left it as it is. One is current, we convert it to the "constant" (right-click on it -> Both -> Constant). And one after current, this one have to be removed (right-click on it -> Remove).
  6. Now test it. Pay attention, that loop will always break at the very first frame of you animation, so you need to break it in the right place.

Detailed explanation

'Green guy' (Animate mode off icon.png) - Static Parameters - is a guard that says "You shall not pass!" to the animation. So when you attempt to change such parameter in animation mode it just changes the usual way. It's done to prevent unnecessary parameters to be animated, e.g. Blend Method.

Setting "Duration" to "EOT". If you set it to 0f, then the whole animation will stop, because you try to play it from 0f ("local time") to 0f ("Duration"). And EOT means it'll continue to play your animation to the end of the time...

Removing waypoint after current one. If you skip this step, then at the next waypoint "Duration" parameter will be restored to the value before current waypoint. It's a standard Synfig's behavior, but there's a magical button somewhere that can change it.

Converting current waypoint to the constant. Without it, "Duration" will be smoothly interpolated from value you set to the EOT and the constant type will just set immediately at the waypoint. Interpolation can be a bit confusing sometimes, so you better read this about waypoints.


Visualized Example

For example, suppose:

  • Link Time is 5s
  • Duration is 3s
  • Local Time' is 4s

And suppose that the Time Loop layer is applied over an existing animation. The "Link Time" and "Duration" specify that the section from 5s to 8s in the children layers will be looped. The "Local Time" specifies that this loop will be at the beginning at 4s. (And so also therefore at 1s, 7s, 10s, etc).

This is how the mapping actually works:

real time child time
(symmetrical = true)
child time
(symmetrical = false)
0 7 4
1 5 2
2 6 3
3 7 4
4 5 5 (local time = 4; link time = 5)
5 6 6
6 7 7
7 5 5 (duration = 3, so loop repeats after 3 seconds)
8 6 6
9 7 7
10 5 5

Specifying a huge number for the Duration parameter effectively turns the Time Loop layer into a Time Shift layer. The Link Time and Local Time parameters controls which time in the children lines up with which time in the Time Loop layer, giving the amount of the timeshift, with both positive and negative differences working as expected.

Contrived Example

Download and examine this example file: Time-loop-demo-0.2.sifz

It's a 10 second animation, and shows 2 circles. The top one moves linearly from the left to the right. Its position is marked by static text digits 0 through 10.

The other circle is an identical copy of the first one, with the same waypoints, but it's inside an Group layer. The parameters are:

  • Link Time: 5s
  • Duration: 1.5s
  • Local Time: 2s
  • Symmetrical: true

So as time=2s, the top circle is at position 2 (local time) and the bottom circle is at position 5 (link time):

Image:Time-loop-demo-0.2-2s-0f.png

The loop is 1.5s long, so the bottom circle is also at position 5 every 1.5 seconds before and after this point in time, for example at t=3.5s and at t=8s:

Image:Time-loop-demo-0.2-3s-12f.png Image:Time-loop-demo-0.2-8s-0f.png

The following two images show the positions at t=0s and t=3s. The loop starts at t=2s, so it's also at the start at t=0.5s. So at t=0s it's half a second before finishing the previous loop. And at t=3s the same is true, but 2 loops later on:

Image:Time-loop-demo-0.2-0s-0f.png Image:Time-loop-demo-0.2-3s-0f.png

There's a rendered copy of this example on YouTube, and it's also available for download: Time-loop-demo-0.2.avi‎.


Languages Language: 

English