Gradiant Wipe Using Video Sequencer

Hi all,

I am about a week old to blender so sorry if this is an ignorant question. For my first ‘get my feet wet’ sort of project I’m just using the video sequence editor to combine some video clips and images.

My current ‘problem’ is that I would like to create a wipe transition using a gray scale gradient image (where the transition follows the gradient). This is easy in most video editors, but I’m trying to figure it out in Blender. After a lot of Googling, I seem to be coming up empty handed. Blender seems to be very featureful/powerful so I’m guessing it’s easy but…

Thanks much!
Kevin

I think you could do this by making a scene that uses a plane taking up the camera space, and map a blend texture(gradient) to an empty. Locate the empty at on side of your camera, keyframe the locationwith I, and then move up 30 frames and move your empty to the other side and keyframe it. You can then add the scene as a strip to your sequencer, and use the rendering to create the wipe effect. I will see if I can make a quick example.

If you just need a wipe, then you can use the effect strips to choose ‘wipe’ and that can do it their, but you need to add the strip to the portion of overlap between the two individual shots.

I mean, select both strips you want the wipe to affect, and then hit shift A and choose effect, then choose wipe.

Thanks much for the replies. I’ve played with the wipe effect, and yes for a normal wipe it’s fine. What I’m looking for is a gradiant wipe (maybe that’s the wrong name). What I’m use to in other video editors is a wipe where you can specify a gray scale image that defines how the wipe works.

Here is a video of someone demonstrating this in After Effects…

Thanks,
Kevin

Alright let me see if I can figure it out :wink:

Well, so far I have been trying to make a meta strip of two color strips, balck and white, one above and one below an extended image rendered of clouds. I used cross effects to transition the black into the cloud image, then another cross to transition the clouds to a white image. I made that a metastrip, then used it to transition from black to full image of another imported image. Sorta worked, but I think the compositor might be better suited to doing something like this. I will try tomorrow when I get a chance.

Wow, that’s quite a process! I did come across someone using the compositor to do something similar (I think)…unfortunately now I can’t find the website. He was using a couple of image inputs, a mix node, and a composite node. I tried to follow what he was doing, but I have very little clue how to use the compositor at this point!

Thanks so much for your efforts!

Not at blender at the moment but what you describe is an animated alpha channel. You want to use a B&W image to change the transparency of one strip over another. This should change based on the value of the B&W image.

Sorry, I just can’t have a go at it at the moment.

3pointedit is right - I think the best way is to make an animation of a texture’s values on a plane (cloud, voroni,etc) with the values of the color ramp being keyed, then render that to a strip like he said. Then that would be the mask you use to change the alpha of the strip including just the titles or whatever you wanted to use the wipe on.

check the second link in my sig

Hi guys,

Thanks again for your help. I can’t say I understand all of what you are suggesting, but I have some things search for/try now!

Thanks,
Kevin

As the VSE doesnt have a keyer at the moment you cant combine 3 strips. But you could in 2.49

you can do 3 with my method, using RGB instead of grayscale.

Modron, sorry I was talking about keeping it in VSE. It’s less than interactive if you have to go out to Nodes every time you want to do a wipe.

ok, but of note, I have done it with the sequencer before, prior to the addition of composite nodes, using meta-meta-strips, and I gaurantee it is a major pain to do it that way. imo it’s much easier to render it using composite nodes, and then put it in the sequencer.

Hmmm, how can you tip toe around the nodes? Use textured panes in 3D view and animate the wipe as a texture. Just as yucky. As I said you really need acess to an alpha channel in the VSE that can access alternate sources. Dunno how.

I suspect someone will eventually code in functions for these things that work more like a regular cross.