Creating Realistic Fires in
EffectsLab & VisionLab Studio, Pg. 8
Masking the flames
The masking system that is built into
EffectsLab and VisionLab is ideal for making our fire appear to be coming
from inside the window. Due to the perspective on the building in this
shot, we will need to mask the left side of the window, and the bottom of
the window, across the sill.
We will use two seperate Masks for this
procedure. The reason for this is that the flames will have a fairly hard
edge across the bottom, where they come up from the sill. But on the side,
where there will eventually be smoke coming out as well, they will need a
softer edge to blend more with the smoke.
So draw your first mask in the same shape that you see in this
image.
The only really important part is that the top edge of the mask
follows the edge of the sill properly. Click on the necessary points, drag
the last point onto the origin to close the mask, and then click the
Animate tab in the Mask Shape Inspector.
Animate Tab
In the Animate controls for
the Mask, we can adjust the Feather (softness) of the
edge, and the Transparency of the entire mask. These can
be animated to change over time using keyframes.
Also, we can change the shape of the mask at
any time by simply dragging the control points of the mask around on the
Canvas. We won’t need to animate our mask, but it is a very useful feature
for other projects.
For the bottom edge of the window, we want the edge to be fairly
sharp, but not jaggy, so we will add just a slight bit of Feather to it. I
set the Feather to 6. We want the mask to completely block the flames, so
we will keep the Transparency set to 100.
Now we will add another mask, for the left side of the window.
Create a shape like the one in this picture.
Notice that along the lower half of the window, the mask closely
follows the edge. As the flames rise though, it is possible that some of
them would come out around the frame of the window opening. To allow for
this, we can gently curve the mask back away from the window as we get
higher. Set the control points for this mask where you see them in the
picture, and then raise the Smooth Points control to 0.61. This smooths
out the curves, and eliminates any unnatural corners in the mask
shape.
Now click the animate Tab, and set the Feather to 21.
And there you have it. The flames are all
set, the window is masked, and you are ready to render the effect out and
see how it looks.
