9

Surface Approximation Rollout 1249
Method=Sp atial and Cur vature
Edge=5.0
Distance=5.0
Angle=2.0
Merge=(Unavailable)
Advanced Parameters > Minimum=0,
Maximum=4
Save Tessellation Preset group
Click a button to save the current Tessellation
Method settings as a new Low, Medium, or High
preset. These values are saved in the 3dsmax.ini
file.
Note: There is a separate Low, Medium, and High
preset for B ase Surface and Displaced Surface
approximation. Check whether Base Surface or
Displaced Surface is on before you use the buttons
in this group box to save a custom preset.
Customizingpresetvaluesoverwritesthedefault
presets. To restore the defaults, you can re-enter
the default preset values shown above, and then
save them with the corresponding button. You can
also restore defaults by editing the 3dsmax.ini file
to delete the custom preset values.
When you customize the preset values, there is no
necessary correla tion between the button names
and the quality of surface approximation. The
software has no way of knowing how "good" a
tessellation is, and you can save a very high-quality
surfaceapproximationintheLowpreset,for
example.
Tessellation Method group
Thecontrolsinthisgroupboxaffectthedisplay
of the NURBS surfaces in either viewports,
ifViewportsischosen,orbytherenderer,if
Renderer is chosen. You can choose b etween five
algorithms. Each approximates NURBS surfaces
by tessellating them in a d ifferent way.
Note: When Viewports is chosen, you must also
choose Mesh Only in order to see the effect of the
Mesh Parameter settings in wireframe viewports.
Generally speaking, if the preset values you have
chosen give good results, you don’t need to adjust
thecontrolsinthisrolloutfurther.Usethemifyou
encounter problems with the preset alternative.
Tips
• Viewport Tessellation: The tessellation method
creates the mesh, so if you modify the NURBS
object with Mesh Select, choose the method
that gives the result you need. If you use
modifiers heavily, Spatial or Parametric might
be better than Cur vature, because of their
regular tessellation. Curvature-dependent
tessellation can cause problems with some
modifiers.
• Renderer Tessellation: Spatial and Curvature
usually obtains the most accurate rendering.
Curvaturecanbethemoreefficientchoice
when you render animated surfaces.
Regular—Generatesafixedtessellationacrossthe
surface based on U Steps by V Steps. Increasing
these parameters increases accuracy at a cost of
speed, and v ice versa, but in general this can be t he
quickest and least accurate way to approximate a
NURBS surface. Very low values for U and V Steps
using the Regular method u sually doesn’t provide
good results. Model complexity increases slowly
as U and V Steps values increase.
Para m et r i c—Generate s an adaptive tessellation
based on U Steps by V Steps. Low val ues for U
and V Steps using the Parametric method often
provide good results. Model complexity increases
rapidlyasUandVStepsvaluesincrease,so
take care when you switch from Regular, which
generally requires higher U and V values, to
Parametric, where lower U and V values generally
suffice.