Re: Walk-through walls, windows or any objects in after effects 7.0
by Catch-Me
on
Dec 14, 2006 at 1:09:20 am
Hello
Good Day
I would like to make a video scene, where an actor will walk-through the wall, window or an object, afterwards the actor will disappear. How can I make this scene in After Effects 7.0? Can anyone please help me?
Re: Walk-through walls, windows or any objects in after effects 7.0 by yikesmikes on Dec 14, 2006 at 6:32:03 am
If I'm understanding you correctly, the talent walks toward, then through a wall, disappearing into the wall. You can do it quick and dirty, by Mask Expansion of a mask that fits your talent. Select the green screen layer of your talent, Layer>Auto Trace (current frame, Tolerance 1 pixel, Threshold 1 percent). Then copy the mask from the Auto trace layer, and paste it onto the talent green screen layer. Then animate the Mask Expansion from 0 to 100 pixels or whatever it takes (depends how thick the talent is) over how long you want the walking through the wall to last.
Once the walk though starts, a little mask Feather (8 to 12) will probably make it look better.
Or you can animate the Mask Shape over time, but that can be tedious.
Stylize>Roughen Edges can give the fiqure a little more texture (a stucco or brick wall?).
Re: Walk-through walls, windows or any objects in after effects 7.0 by Catch-Me on Dec 15, 2006 at 1:07:30 pm
Thank you very much for your quick reply.
I think you got my points. I tried several times, I failed. Could you please explain a bit more? Or do you have any sample of this effects, in text format or video format?
Thank you once again and waiting for your soonest reply.
Re: Walk-through walls, windows or any objects in after effects 7.0 by Catch-Me on Dec 16, 2006 at 1:47:53 am
Thank you for your reply.
Yes, the actor walking through the green screen background. However, I got another footage, where actor walking through the brick wall. Please advice me.
Re: Walk-through walls, windows or any objects in after effects 7.0 by yikesmikes on Dec 16, 2006 at 9:48:46 am
Overview: Auto Trace makes masks for the keyed walker, then put them on the walker layer and animate the Mask Expansion for 0 to a negative number. Note: Alternative method with Matte Choker below (even quicker and dirtier).
OK, I'm not expert on this, but I see why you had trouble with what I said earlier. I was using a still of a human figure (with Alpha), so my instruction for doing Auto Trace, set at "Current Frame" was wrong, Since the Walker is changing shape constantly, Auto Trace needs to be set to "Work Area" (adjust the work area to where the actor just steps into the wall then disappears. The other setting, small numbers for tight masks, were OK.
The new Auto Trace layer that appears gives you masks (can be many, and for each frame of the work area). "M" exposes the masks, select the Mask Shape for all of them, this selects all the mask keyframes, then Copy.
Select the Layer with the walker that's keyed, go to the spot where you set the beginning of the work area, so the masks start at the same pace you copied them from (and therefore match the walker), then Paste, you should get all the masks put onto the walker layer.
You can now delete the Auto Trace Layer. When I ran the auto Trace on this it also applied a Track Matte to Alpha Matte to the Walker Layer, so I had to change the Walker Layer back to TrkMat: None.
Now with all masks selected, twirl down to "Mask Expansion", and keyframe from 0, to -50 (or whatever it takes, -100?) until the masks shrink to nothing and the walker disappears. Also feather all the mask, 3 to 5 or to taste.
If the Wall layer is below the Walker layer you should have a quick walk-through-the-wall.
I just tired this on green screen footage and it seems to work although like I said it a bit quick and dirty.
You can get a similar effect without the masks by adding a Matte Chocker (Effect>Matte Tools>Matte Chocker) then animating the Geometric Softness 1, from 0 to 100 (to get 100, right click the blue number, then Edit Value then change the Max Value in the pop-up. This only works all the way if the walker is relatively small.
Maybe there's a better/easier way, if so, I hope someone chimes in.
