For a continuous loop you need the first frame to continue the last frame. This usually means that some level of video compositing is involved. Show us what you got there
But also in doing so you see the shot of when starts again. It is not a simple cube. A simple cube I'm able to do so in an infinite loop fluid.
Not I can show the file, the client does not want.
You can show an example please?
o.k that all depends on what you have there and how good is good enough, but if we are talking video (meaning it's not keyframe animation), then a a dissolve loop could work in many cases. the technique is you cut the clip in the middle, swap the front of the clip to the end, and the end of the clip to the front. then you overlap the two parts in the middle by about 10 frames or more. Then dissolve the front layer from 0 to 100, and the finished piece will loop seamlessly.
this is explained in this tutorial:
The first frame and last frame must not be the same – otherwise you get a slight pause.
Let's say you are rotating a cube on the y axis. Set a keyframe at 0 and 0º at frame 0. You want you animation to take 20 frames so move to frame 20 and set the y rotation to 1 and 0º or 360º. Now move the CTI (current time indicator back one frame and press the N key to set the out point of the composition. Now trim the composition to the work area. Next render your movie to a format that you can open in Photoshop. Open the movie in Photoshop and use the legacy export for the web to export your animated gif. Make sure that you set the dialogue in the export panel to loop the gif. You're done.
One more thing. If you want an animation where something moves or rotates and then stops for say 10 seconds like in a web banner then just note the frame where you want the animation to stop or set a hold keyframe for that frame, then move ahead one frame and start the action again with a regular keyframe. Then when you are in photoshop move to the frame where the animation is supposed to pause and set the duration of that frame to 10 seconds. You can end up with a nice 1 minute animation that is only a few frames long and very small using this technique.
Excuse me but I did not understand the process. I so far have not found a technique that does see the shot of when starts from scratch, or fade (with the technique of cutting the video in half) in the middle.For example this video: example.mp4 - Google Drive would you be able to put it in a continuous loop notice no artifacts... shot or visible fading? You can make a practical example, and attach the after effects .aep files? So we understand much better. Thank you so much.
Your example cannot be made into a seamless loop without some serious manipulation because there are no frames that are nearly identical. It starts here with the girl in the shot:
and it ends here with both out of the shot except for a bit of the edge of the man's shoulder:
The only option would be to shorten the shot and find a couple of frames where they were in approximately the same position on each end of the shot so you could make a seamless transition. Look at the position of the boxes. Nothing matches.
The only way you could make that clip into a seamless loop would be to find a spot where you could closely match the position of the background, find another spot where you could closely match the position of the girl, closely match the position of the boy, then rotoscope both the girl and the boy so you could fill in the background - which would involve some motion stabilizing and cropping, then you would adjust the in and out points of the layers and b build the scene so you had matching frames at each end.
The easiest way to see if you have a shot that has matching frames is to duplicate the layer, set the opacity of the top copy to 50% and set the blend mode to Difference, then pick a spot where you think you might get a match and start sliding the top copy around in time. When you get a match you set a marker for both layers then reset the top layer so the original in and out point match, trim the comp to the markers using the work area and test out your loop. The process would look like this for matching up the guy. First mask out the guy then duplicate the layer, set the opacity to 50% set the blend mode to difference, drag the top clip and the cti around until you find kind of a match, set markers, reposition the top copy and set the in and out points of the work area to the markers and test.
As you can see this clip isn't going to work very well without a lot of manipulation. The closest I could get was to get the front of his face to kind of match up. (note: I added an adjustment layer with exposure to brighten up the scene to better see the edges:
You will have better luck if the shot has a locked down camera or obvious closely matching frames. Given a half a day using stabilization, roto, morphing, time remapping and background replacement I could probably get this clip to seamlessly loop but it would not be worth the effort unless some crazy client was willing to pay my full rate for the work. If it had to be done I'd probably charge about $1,000.
That sort of clip will not lend itself to seamless looping via the technique posted, as Gerard rightly pointed out.
It needs to be reshot with the camera either not moving or returning to almost exactly the same spot at the end, and have the people walk in at the start and walk out at the end.
Or, if reshooting is not an option, you can add a logo fading in at the end, followed by the logo fading out at the start. That would give a nice buffer for seamlessly looping and has the added benefit of promoting the customer at the same time.
If that wont go over with the client well, you could do a zoom trick like this:
Don't think I can embed that here, and hosting sites mess with the start/end, so I put it on my own site. If that sort of link is frowned upon here I trust somebody will let me know! I'll remove it right away or a moderator can do so. Basically all I did was resize and reposition the clip in the first and last frames to make the view almost identical, again as Gerard rightly pointed out, is needed, then did the cross fade described above.
The loop is still obvious, but mostly because of the watermark. It would be nigh-undetectable with no watermark. Download the clip and loop it in playback to see how little work is needed to polish it up to pro level - that was done in just a couple minutes. Took longer to upload it and make this post than to create the video!
If you want the AE Project, it is here: http://www.sockratease.com/things/example.zip