Creating Natural Materials in Cycles - Blender 2.6 Cycles: Materials and Textures - page 92

5. Now we need to expose the values to modify the material from the inter-
face. From the Fac input of the first Multiply node, click and drag a link
to the left border of the group. In the newly appeared input socket name,
enter Big waves strength . This value actually drives the strength (the
multiplication value) of the Big Waves bump summed to the main Sand
Bump .
6. Do the same with the second Multiply node and rename the input as
Granularity . Again, this value will drive the amount of multiplication of the
sand grain to the rest of the bump effect.
7. Now click on the Value node inside the Big Waves frame and press X to
delete it. Click and drag to the border around the second Value socket of
the first Wave node and rename the exposed new socket as Big waves
repeat . Also, Click and drag a link also from the second Value socket of
the second Wave node and connect it to the Big waves repeat socket.
By clicking on the upper little arrow on the socket side, move it up just
before the Granularity frame.
8. We also need to expose the Multiply node inside the Total Bump
Strength frame, by dragging the second Value socket. Rename the new
socket on the interface as Bump strength . This is, in fact, the value for
the overall bump of the material.
9. Press Tab to close the group. On the interface we have the controls to
increase or decrease the overall bump effect, the sand grain, and the
waves' strength and scale/repetition. We can have exposed even more
values, for example, also the first bump amount for more finer tweaking,
and the two color inputs in the Sand Color frame.