This
is a quick method of faking camera
focal blur. Its not exactly acurate
but gives good results for a heavy
workflow project that could take a
lifetime to render with conventional
depth of field effect of any software.
With this principle you can get nice
blury backgrounds or defocus near
objects. In this example i made a
little ufo flying around a field the
objective of the tutorial is to blur
the mountains in the back with a smooth
transition towards the front in adobe
After Effects(Æ).
First
the initial movie is rendered
in the 3d software. This is
the finished product but without
focal blur this we will do
in Æ. If you like to
render several passes like
specular, diffuse, reflection,
etc... first composite all
of those passes into one video
so youll only have to worry
about the DOF.
Secont
step is to use the zdepth
channel or fog if you dont
have multy pass renderer.In
the fog case I applied a totally
black material to all the
objects in the scene. Add
fog, notice that it is totally
white.
This
effect creates a simple black
and white mask(like a zdepth
channel) that we can use in
Æ to blur. Also remove
all the lights in the scene.
The white parts are the ones
that will be blured and the
black wont. The smoth grayscale
transition is the soft blur
that tells us how far an object
is. the more contrast you
apply to the fog the less
subtile the effect will be.
We call this one z deth.
Create
a new project. In it a new
composition that matches exactly
to the frame rate of your
videos and the size. Also
import the two rendered videos.
The final movie and the zdepth
movie.
Place
the movies in the composition
(final and zdepth). Its important
that both are in the exact
same place and start in the
exact same time.
Here
in the time line starts the good stuff.
Notice that ufo.avi was placed twice.
this is necesary to acomplish the
effect and to use the zdepth mask.
The location of the zdepth layer is
not important because itll be invisible
at the moment of rendering the finished
effect. I repeat: is very important
that all the movies start at the same
time. Also i colored each layer to
diference their function in the effect:
Light gray layer ufo.avi- this layer
wont have any effect. itll be the
one that remains focused.
Dark gray layer- Doesnt matter its
location. It will be hidden all the
time. Only for use as mask source.
Orange layer- this layer will have
all the effects applyed to it. Its
very important that this one remains
on top of the others at all times.
Select
the Orange ufo.avi layer and
go to the menu/effects/chennel/set
matte. This will add the set
matte effect to this layer.
Also once you are there go to
menu/effects/blur & sharpen/gaussian
blur. Now we will set this effects
properly.
Use
this settings in the effects
of the orange ufo.avi layer.
The amount of blur is up to
you. but dont exeed the blur
amount because it wont look
blured, it will look washed
out.
Thats
it! now go to menu/composition/make
movie... and render the final
product in the file format you
like. Remember to set all effects
active.
Hope
you liked this tutorial. If
you want to add blur to the
objects near the camera just
invert the fog render. play
with the levels to tweak the
focus.
Light gray layer ufo.avi- this layer
wont have any effect. itll be the
one that remains focused.
Dark gray layer- Doesnt matter its
location. It will be hidden all the
time. Only for use as mask source.
Orange layer- this layer will have
all the effects applyed to it. Its
very important that this one remains
on top of the others at all times.
