PRG Mbox Designer Manual 3.8 - Manual (Page 144)

136 MBOX ® MEDIA SERVER USER MANUAL
b. Control Type Pop-up: This is where the property of the screen that is to be controlled is selected -
position, texture position, rotation, etc. Refer to
"Screen Object Control Types (Units, Typical Scale
Value)" on page 146 for more details on the control types.
c. Scale/Counts Pop-up: This switches between the two methods of scaling the incoming Art-Net data to
apply it to a control.
1) For example, if you are receiving a 16-bit offset value for X Positioning, but only ever need to move
a screen object 100 pixels left or right, then you may want to relate a range of 0-65535 to a range of
negative 100 to positive 100. Since the total range of movement is 200 pixels, your Scale value
would end up being 200/65535 = 0.0030518. Alternately since the movement on either side of the
default value is 100 pixels, the scale could be calculated as 100/32767 = 0.00305185 .
2) Alternately, counts (typically used for linear position controls) equates to the number of Art-Net
steps (counts) received per pixel of total travel. With the above example, since you are using 32767
steps to move the screen object 100 pixels, your Counts value ends up being 32767/100 = 327.67
3) The two methods are just the same information presented in a different ways, one is the reciprocal
of the other: 100px/32767counts = 0.00305185 (scale = pixels per count) and 32767counts/
100pixel = 327.67 (counts = counts per pixel).
Note: The sign (+ or -) of the scale value is be used to invert the property's direction of adjustment relative to the
incoming data.
d. Min and Max: These values are typically used to limit the travel of a linear control used for scenic
tracking to a specific number of pixels; so as to keep the screen object (2D or 3D) or its applied texture
from moving too far if incoming tracking data values exceed the expected limits. Their use with non-
linear controls may not be necessary, as the scale/counts value for non-linear controls tend to be set
more precisely.
e. Offset: The Offset value is used to preset a value for a control that does not respond to external data.
Offset is typically used with the Repeat controls, but can be used to move or rotate a screen object a
fixed amount. When using an offset value the Scale value should be set to zero (0).
Step 12. The opacity control that you have added now needs to be configured to respond to some Art-Net and also
to have the appropriate scale. First of all, use the universe popup to set the Universe to "(0) Universe 5", and
leave the address at 1.
Step 13. Choose "8-bit unsigned" for the data format, and "Opacity" (of course) for the control type. You'll need to
do some math for the stride value - assuming three channels per screen object (opacity, X position, & Y
position), nine screen objects, 3 x 9 = 27. And finally for your scale, an 8-bit control has a range of 0-255,
and the opacity parameter has a range of 0.0-1.0 so you need to divide 1 by 255 = 0.00392157. You don't
need an offset, min, or max.