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1568 Chapter 16: Material Editor, Materials, and Maps
by other surfaces, and bright areas that are exposed
to the en vironment.
An example of AO applied to a scene
One important aspect of AO is that the user
cantunethedistanceitlooksinforoccluding
geometry.
AO looked up within a shorter radius
Using a radius creates a localized AO effect; only
surfaces within the given radius are considered
asoccluders(whichisalsofastertorender).
The pract ical result is that the AO provides nice
“contact shadow” effects and makes small crev ices
visible.
The Arch & Design m aterial gives you two ways
to utilize its built-in AO:
• Traditional AO for adding an omnipresent
ambient light that is then attenuated by the AO
to create details.
•UseAOfordetail enhancement together with
existing indirect lighting methods such as Final
Gathering or photons.
The latte r method is especially interesting w hen
using a high ly smoothed indirect il lumination
solution, such as a high photon radius or an
extremely low final gather density, which could
otherwiselosesmalldetails.ByapplyingtheAO
withshortraysthesedetailscanbebroughtback.
Round corners
Computer-generated imagery tends to look
unrealistic, par tly because edges of objects are
geometrically sharp, whereas most edges in the
real world are slightly rounded, chamfered, worn,
or filleted in some manner. This rounded edge
tends to “catch the ligh t ” and create highlights that
make edges more v isually appealing.
The Arch & Design material can create the illusion
of rounded edges at render time. This feature is
intended primarily to speed up modeling, so that
you need not explicitly fillet or chamfer edges of
objectssuchasatabletop.
Left: No round corners; Right: Round corners
Thefunctionisnotadisplacement;itismerelya
shading effect, like bump mapping, and is best
suited for straig ht edges and simple geometry, not
advanced, highly curved geometry.