operaguy opened this issue on Dec 28, 2011 · 171 posts
bagginsbill posted Mon, 09 January 2012 at 6:55 PM
LK,
If you were to use a map untransformed (no math nodes adjusting it) then obviously you have only the numbers to work with, multiplied by whatever you type into scale.
A map can create values between 0 and 1, inclusive. Black is 0. White is 1.
Connect that to any number parameter and the value, Pv, of the parameter modifies the node, N, as follows:
Pv * N
Simple multiplication.
So with an incoming map that is 0 to 1, multiplied by whatever you put in the scale, you will have Black = 0, and White = Pv.
If you plug a map directly into a scale with Pv=1.5, for example, then the map value of 255 would mean 1.5 scale. A map value (assuming linear gamma=1) of 200/255 would be 200/255 * 1.5 = 1.176. A map value of 0 would still be 0 because 0 times anything is still 0.
If, on the other hand, you do additional math between the map and the Scatter node, then you can make it be anything you want.
Consider if you insert a Math:Add node, with both Value_1 and Value_2 = 1, and you plug the map into one of those. Then you use this to plug into Scatter.Scale. What is that?
Well the map is [0, 1]. Then the Math:Add node is [0, 1] + 1, giving [1, 2]. The map now means black=1, and white = 2.
If you plugged that into Scatter.Scale, with the parameter value Pv = 1.25, then black (1) is multiplied with 1.25, giving 1.25, and white (2) is multiplied with 1.25 giving 2.5.
See how that works?
It's simple arithmetic. You can transform the black value and white value to anything and then it is multiplied with the parameter value.
You want black = .2 and white = 7?
Then make a Math:Add Value_1 = .2, Value_2 = 6.8 and plug the map into Value_2. This node now converts the map to the range .2 to 7. You could then plug that directly into Scatter.Scale, with Pv = 1 and you'd have scale controlled from .2 to 7 by the map.
There is no end to the combinations you can make.
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