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  1. Can Blender VSE do something like in this video ?

sample

I have been looking on the net for motion trail effect, ghost effect, but cannot seem to find a way to do this.

  1. Would I have to use a script to achieve this?

  2. If so can someone please give me some pointers.

Kind regards,

Reggie.

Addition) I've found this, with linked script. Could this be modified in some way?

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    $\begingroup$ One way is by duplicating the strip and offsetting the duplicates it by a few frames. Turning down the alpha of the duplicates will produce a sort of ghosting effect. (the "alpha over" blend mode should be selected for this to work as expected) $\endgroup$
    – gandalf3
    Jan 16 '17 at 11:15
  • $\begingroup$ Thanks gandalf3, i think that's what the scrip is doing. $\endgroup$
    – reggie
    Jan 17 '17 at 13:42
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Rather than doing this in the VSE you can create this effect using a feedback technique similar to How to do this type of trailing effects where the previous frame is held over to include in the current frame. The only real difference is in masking out the current frame so as to overwrite all but the background each time.

The setup of the scene is the same (ie, a camera pointing at the plane) with the following material on the plane :

material

Here the feedback is handled by the bottom branch - with the Image Texture pointing at the location of the render result, offset by 1 frame to pickup the previous frame. The top branch injects the video (filed infront of a black background) with the Subtract used to darken the image (this was used as a crude way to remove background artifacts since my video background wasn't perfect) with the Less Than used to detect the 'foreground' so that the feedback can be cut out wherever the new image is above a certain threshold. The images are combined and the Emission with a value less than 1 effects the fade out as the trail ages.

This produces the following result :

result

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    $\begingroup$ This is nice, but everything has to be prerendered for this to work $\endgroup$ Jun 3 at 17:47
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    $\begingroup$ @placidchat, what do you mean by ‘prerendered’? It’s rendered on a frame by frame basis - no need to render out the whole animation first. $\endgroup$ Jun 4 at 12:18
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    $\begingroup$ The 2 image texture nodes need 0002.png and proxy_25.avi, which is why i assumed this to be the case. Isn't it so? $\endgroup$ Jun 5 at 3:08
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    $\begingroup$ @placidchat No, actually the 'proxy' is simply the source video of a hand in this case. The '0002.png' is set as an image sequence but pointing at the render result folder with an offset of '-1' so as to pick up the render result of the previous frame - this is what produces the feedback. There's no need to pre-render at all. In fact, you can place objects in front of the camera and get the same effect but with meshes instead of video - see linked answer here : blender.stackexchange.com/a/213312/29586 $\endgroup$ Jun 5 at 7:56

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