DTE tutorial part 5 : Creating component 2 of texture A                                                            Feb 2000
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Open Altitude filter in texture B To find out what makes Basic Altitude work , we'll open it in the DTE for a closer look. 
Open the DTE for texture B (rosy button top left) and click the pebbles for phase and noise, if the palettes aren't there. 
(If you left the DTE previously with Noise and Phase pallet on, they'll still be there when you open it again).

This texture has a noise and a phase setting of Nothing ( the top left corners of both Noise and Phase palette are grey).

Open the Filter Dialog (if it isn't there) for the first component by clicking the pebble in the bottom of the DTE or the blue circle in the top righthand corner of the component.
The settings are (approx.) a = 2.2 b = - 0.1 mode = X(a*Altitude+b).

The mode indicates that the noise pattern will depend on height ( Altitude ).
If factor a is higher, the noise pattern will change more quickly from black to white,
while adjusting factor b shifts the change up or down. 
Factor c is not in the equation,which means it has no effect.

If you look more closely at this component , you'll see that C (Colour) and B (bump) are turned on and A (Alpha) is off.
A bit confusing since the Alpha information is still driving the diffusion in our material.
Well even if A is turned off , the alpha information is still there.
If you have more than one component, the alpha information will come from those components which have A turned on. 
If all the A's are turned off then the alpha information from all components will be used.

 

 


 
Choosing the mode for the noise filter Clicking on the formula in the filter dialog opens a choice of several modes.
Some of these ( Quantize, Sawwave,..) will directly influence the noise pattern (for instance make the darker parts smoother and the lighter parts noisier,..).

The others (like Xb + (a*Altitude), X(a*Orientation + b) will influence the pattern according to altitude or  orientation or slope.

These come in handy if you want the pattern to differ on a steep slope versus a horizontal surface.Or if you want to colour one side of trees green with moss.

Choose the Altitude dependent mode and make a note of the settings for a and b.
We'll use them in texture A.

How can a noise filter work when there is no noise ( = a noise setting of 'Nothing') ?
Well, think of a setting of Nothing as a featureless sheet with no pattern in it. 
You can still colour it and change its level of white to black with a filter like Altitude.
Filters like Quantize and Sawwave that influence 'real' noise patterns will have no effect.


 
 Now we'll recreate this component in  texture A ,so close texture B with the cancel mark ('X') and open the DTE for texture A.
Creating a second component Click on the darkened 2 in the top left corner of the DTE : this will create a second component.

Click on C , A and B of the second component till only A (alpha)  is highlighted, because that's the one we are going to use.
The colours will disappear and only alpha information will remain.

Click the rosy button top left of the second component to switch the noise palette to the second component.
You could do this by clicking the second position of the blue ball in Noise palette too.


 
Setting the noise to Nothing Click on the top left corner of the Noise palette to open the Noise Dialog and click on the setting for Type.
Select Nothing from the list and leave the Noise Dialog with the check mark to enter your settings.

If you happen to get a component 2 with a phase ( the top left corner of the Phase palette is green) , open the phase dialog by clicking on the top left corner of the Phase palette and set the type to Nothing too.

Now we have a plain second component without a noise pattern and without phase.


 
Adjust Noise filter in component 2 We now need to set the Noise filter to Altitude mode and adjust the parameters a and b.

Open the Filter Dialog (if it isn't there) for component 2  by clicking the pebble in the bottom of the DTE or the blue circle in the top righthand corner of component 2.

Click on the formula and select X(a*Altitude+b).

Drag on the graph itself ( left - right to adjust a , up - down to adjust b ).
The faster you drag the larger the change in a or b . The slower you drag the smaller the change to a or b.
You can also drag on the values behind a or b to adjust them separately.

If factor a is higher, the noise pattern will change more quickly from black to white,
while adjusting factor b shifts the change up or down. 
Change a to about 2.2, b to -0.1 .
Factor c is not in the equation, it has no effect : we don't need to adjust it.
(Try changing a to -2.2 and b to 1.8 for a moment. The alpha information will be upside down : black on top, white at the bottom)


 
Opening the Texture Library To save this texture to the texture Library we click the UPPER button on the right of the combination window. 
The bottom one would randomize our texture, ruining all our efforts. 
Ctrl(Command)-Z would save us unless we accidentally clicked the randomize button twice.
Put it somewhere in Rocks and name it.You could even delete the first one you made and save this one in its place. (go to page 3 for a detailed explanation on saving textures)

Make a habit of saving your textures regularly while working on them. You can always delete the unwanted ones from the Texture library later, but it bites to lose hours of work because you click the wrong button or your PC crashes.


 
Using channel A to drive the Diffusion Leave the DTE with the check mark to enter our changes : the middle windows (alpha) of each texture look identical now.

At the moment , we are using texture A for color and bump and texture B for alpha.

Click channel A for Diffusion : the alpha information from texture A is now driving the diffusion.
If we leave the Materials Lab (with the check mark !) and open it again the  texture Basic Altitude will be gone, because it is no longer used.

Your preview looks dark all over again, doesn't it ?
Don't worry : go to part 6.
 

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