#Light Channel?
03-Feb-95 02:41:10
Sb: #3756-#Light Channel?
Fm: Michael S. Flynn 74551,142
To: Chuck Jones 74761,3211
Chuck,
It sounds as if you don't understand how to add points in the channel
window. Skip this part if you do.
There are three boxes that you can enter values in. One at the top above
all the buttons, and two at the bottom below all the buttons. The "M" and "B"
buttons just above the two bottom boxes adjust the Magnitude and Bias of the
spline you have in the window. Click on one of the points in the window to
highlight it, and then click "M" or "B". The button will remain depressed
untill you click it again to turn it off. When it is on, move the cursor into
the windows area and drag it left or right and you will see the spline change
shape that is controlled by the selected point.
When you click on one of the nine upper buttons, say "R" for "Red", a
number appears in the top box, for "R", "G", or "B", the default is 255. You
can make it higher or lower, but in the case of "R", "G", "B", "A", and "T",
the default makes perfect sense. Since you can't have a color value outside the
range of 0-255, or a light type higher than 7, you can see why. The number that
you type into the top box determine the number of units above and below zero
that the window will display. It is pretty much the same as selecting "Grid
Size" in SCULPTURE, only there is no grid showing.
Now that "R" is selected, choose "File" then "Add" to add a control point
to the window, or press "A" on the keyboard. Now if you move the cursor into
the window and move it around, the point will move up and down. If you only
have a single point, it will always stay anchored to the left edge at "Frame
1". As it is moving, watch the two bottom boxes; the upper box should have a
value of 1. This is the box where you specify which frame you want a control
point to reside at. It is affected only by moving control point in a
left-right/right-left (horozontal) plane. The bottom box will shows changes
only an up-down/down-up (vertical) plane. So if you have selected "R", and
added a point, then moved it up or down 187 units, the two bottom boxes would
read 1 and 187. Now if you want the red color to change to 244 over 11 frames,
add another point, type "11" into the upper of the two bottom boxes, and "244"
into the lower. You can now make the points smooth or peaked, and adjust the
mag and bias. If you want the exact same setup for the "B", you can select the
whole spline in the window, copy it, and then click on "B" and paste it. That
is all there is to adding points in the channel windows.
Intensity in AM is kind of misleading. Fall-off is a little easier to
understand. A Sun has no fall off, therefore, no adjustable intensity. The
other sources can have their intensity, or fall-off adjusted by by using the
Distance parameter. If you select a unit of 100 with the "D" button, fall-off
begins at 100 units away from the light, with objects beyond 100 receiving less
light, and object closer that 100 units receiving more light. If you haven't
specified a "D" parameter, fall-off begins at whatever unit distance the
light's target is from the light.
One of the more interesting things that I do in DIRECTION, is to combine
things on a single point. If I have a moving object that will move out of the
influence of the main light source rendering almost indecernible, I use a
hierarchal light segment bulb without shadows, applying the the hierarchal
light segment target at the same point as the figure, with the light it self a
little distance off. Then as the figure moves, it has a light keeping it
illuminated, even when it leaves the influence of the main light source, while
still keeping the mood that the main source is creating.
Hope this helps.
Michael S. Flynn