Cache retime

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Cache Retime 1.2Author: Rob Chapman
here is a compound that could be useful. It may not work for you but it is has so far got me out of a difficult corner. A very simple retime cache node, as we know that the substeps implementation does not always work with all compounds as its based on the simulation using velocity and not point positions and sometimes the director says 'exactly that but 1.5 times slower' and having to go through someone else's complicated ICE tree that has already had umpteen revisions, simply adding substeps is not always the easiest solution right now - if it works at all. But if you have already cached and all you want to do is slow down or speed up the existing cache point positions with a linear interpolate between the frames then this compound might be just for you.

Firstly its annoying that I can't have an external file read node, if so I could make this compound a lot easier to setup. so for this compound to work you have to manually go inside and edit the two cache on file nodes to point to your cache location. Or set up a cache on file node already and copy and paste the path into these two nodes. Once thats done you are good to go. It is still very limited and for now it only interpolates between point positions. This is only version 1.2 it has speed up / slow down amount with a toggle between the two and these values can be key-framed or have fcurves plugged in and if anyone wants to enhance it with rotations and colour etc then be my guest.


local backup: retime a cache.1.2.xsicompound

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Tekano
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Cache retime

Post by Tekano » 13 Apr 2012, 20:56

here is a compound that could be useful. It may not work for you but it is has so far got me out of a difficult corner. A very simple retime cache node, as we know that the substeps implementation does not always work with all compounds as its based on the simulation using velocity and not point positions and sometimes the director says 'exactly that but 1.5 times slower' and having to go through someone else's complicated ICE tree that has already had umpteen revisions, simply adding substeps is not always the easiest solution right now - if it works at all. But if you have already cached and all you want to do is slow down or speed up the existing cache point positions with a linear interpolate between the frames then this compound might be just for you.

Firstly its annoying that I can't have an external file read node, if so I could make this compound a lot easier to setup. so for this compound to work you have to manually go inside and edit the two cache on file nodes to point to your cache location. Or set up a cache on file node already and copy and paste the path into these two nodes. Once thats done you are good to go. It is still very limited and for now it only interpolates between point positions. This is only version 1.2 it has speed up / slow down amount with a toggle between the two and these values can be key-framed or have fcurves plugged in and if anyone wants to enhance it with rotations and colour etc then be my guest :ymhug:
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druitre
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Joined: 25 Jun 2009, 23:35

Re: Cache retime

Post by druitre » 14 Apr 2012, 19:09

Hi Tekano, thanks.

As you say, sometimes you just need a way to change the speed of an existing cache. In my opinion, not just sometimes but practically always :). (Seriously, the ability to make complex and highly controllable changes to the speed of a simulation is one of the main advantages that come with caching, why there aren't factory nodes for this is a mystery to me)

Your compound actually looks somewhat like the one I pieced together years ago following the article on http://www.andynicholas.com/?p=362. It has the same clunky problem involving the two nodes and the same lack of a visual connection between where exactly in the cache it is you're making changes to its playback speed. But thanks for the download!

If you're familiar with After Effects, what I'd like is something like how time remap works there (which is probably how it works in every NLE program): keys are relative to the clip you place them on and have an absolute value that indicates what frame in the clip they represent. You can then shift those keys and fiddle around with the fcurve to get speedramps etc.

cheers, Jasper

Ramon
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Joined: 19 Aug 2010, 22:47

Re: Cache retime

Post by Ramon » 20 Jun 2012, 13:55

load Real flow cache and cache it too icecache, try to use this and particles jumping at time. Not work with RF bin files

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Tekano
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Re: Cache retime

Post by Tekano » 09 Aug 2012, 22:59

Ramon, my apologies! didnt see this until know, also I should have mentioned it won't work on caches where the same particle ID is reused by another particle after it dies. Bin files seem to do this Im afraid. I did do an extended version that worked by defining a box and any particles inside this would have a new persistant ID generated throughout their lifetime and then caches could be stretched this way - but it only worked if your Simulation had a definite start point or emmitter that could be surrounded by this box. So I never submitted it in the end. can try and dig it out if your interested because it was sort of a way to retime *some* realflow bin caches
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