Under Skin Object effect

[Steve Roberts]

Ah. Halloween is coming, judging by the posts lately.

To do this well, you need a 3D app. (Steve the broken record here). But you can probably fake it in AE with the displacement map effect. Make a movie of a white circle travelling around the body. Make the white circle like a white-to-black gradient (ramp), with white in the center going to black. The white areas will displace (move) the skin more. Render this movie, which will be the white moving dot only. Apply the displacement map effect to the footage using this movie as the map.

There should be a displacement map tutorial on the COW.

Keep in mind this is a 2D displacement, up and across. It does not know what “away from the arm perpendicularly” is, so the map won’t easily create bumps you can see in profile.

Anybody else?

[Cody Campbell]

funny enough, Andrew Kramer just put in his blog that this will probably be his next tutorial.

[Aharon Rabinowitz]

In the meantime try playing with displacement maps. You can find some tutorials on that by clicking on my head at the top of the forum.

Aharon Rabinowitz
Email: arabinowitz (AT) yahoo (DOT) com
All Bets Are Off Productions, Inc.
Creative Cow After Effect Podcast
Internet Killed the Video Star: A Guide to Creating Video for the Web

[Darby Edelen]

I would recommend looking at using a displacement map as well. However, I would suggest making use of the effect’s ability to use two different color channels for its horizontal and vertical displacement.

Instead of using a white-to-black gradient you could use something similar to a Normal Map in which the surface normal (a line perpendicular to the surface) is defined by the Red & Green channels in an image. I had never used this before for the Displacement Map Effect, but I did a trial run just now and it worked pretty darn well.

Here is the still image I used for the displacement map:

Feel free to use this image, I can explain how I arrived at it, if you’re interested, in another post.

Then I simply left the displacement map effect on the baby layer (see below) with its default settings of using Red for the Horizontal displacement and Green for the Vertical displacement. I increased the displacement to 15 for both horizontal and vertical.

Note: you have to pre-compose the displacement image in order for any movement of the circle to translate to the displacement map effect.

I animated the circle moving in its pre-comp, with the baby layer below it set to a guide layer. The displacement worked very well.

After that I took some steps to highlight one side of the bump and shadow the other, I can go into those in more detail later if you like.

For your reference, here is the same thing using a white-to-black gradient, notice how the baby’s head bulges outward on the left side (correct) and then becomes indented on the right side (incorrect). It’s a subtle difference, but reason enough for me to use the ‘normal map’ technique:

The white-to-black ‘height map’ technique actually offsets everything to the left and up, where as the red-green ‘normal map’ technique offsets everything equally out from the center of the ‘bump.’

Darby Edelen
DVD Menu Artist
Left Coast Digital
Aptos, CA

[Aaron Zander]

Thanks a lot, now I cant sleep with that image in my head. why did you have to use a baby?

but seriously, thats pretty awesome mr Darby, very creative. Must try this out on another project (which i literally printed to dvd today, but there’ always time for more work)

[Darby Edelen]

[A.Zander] “Thanks a lot, now I cant sleep with that image in my head. why did you have to use a baby?”

Muhahah… I’m so evil >=D

Darby Edelen
DVD Menu Artist
Left Coast Digital
Aptos, CA

[Thecaptain0913]

Andrew Kramar will have tutorial up on his site on this soon, maybe with in the next week or so. Check it out at videocopilot.net

[Darby Edelen]

What, my slap-dash 2 second tutorial wasn’t good enough for you? (;

Darby Edelen
DVD Menu Artist
Left Coast Digital
Aptos, CA

[Thecaptain0913]

lol i havent seen it i just saw the post and thought of the AK because I just heard he was doing the tut today. No morries I’m sure yours is fine lol