#!F-adobe-helvetica-medium-r-normal--18*
#!N 
#!N  #!Risosurf Isosurface #!N 
#!N Category #!N #!N  #!Lcatrel,dxall759 h Realization  #!EL  #!N #!N Function #!N #!N Computes 
isosurfaces and contours. #!N #!N Syntax #!CForestGreen #!N #!N  #!F-adobe-courier-bold-r-normal--18*    #!F-adobe-times-bold-r-normal--18*   
#!N surface #!EF = Isosurface(  #!F-adobe-times-bold-r-normal--18*   data, value, number, gradient, flag, 
direction #!EF ); #!EF #!N #!N #!EC #!N #!N Inputs #!T,1,91,276,461,646 
 #!F-adobe-times-medium-r-normal--14*    #!F-adobe-times-bold-r-normal--18*   #!N TAB Name TAB Type TAB Default TAB Description 
#!EF #!N TAB data TAB scalar field TAB none TAB field 
from which one or more #!N TAB - TAB - TAB 
- TAB surfaces are to be derived. #!N TAB value TAB 
scalar or scalar list TAB data mean TAB isosurface value or 
values #!N TAB number TAB integer TAB no default TAB number 
of isosurfaces or contours #!N TAB - TAB - TAB - 
TAB to be computed #!N TAB gradient TAB vector field TAB 
no default TAB gradient field #!N TAB flag TAB flag TAB 
1 TAB 0: normals not computed #!N TAB - TAB - 
TAB - TAB 1: normals computed #!N TAB direction TAB integer 
TAB -1 TAB orientation of normals #!N TAB - TAB - 
TAB - TAB #!EF #!N #!N Outputs #!T,1,161,321,646  #!F-adobe-times-medium-r-normal--14*    #!F-adobe-times-bold-r-normal--18*   #!N 
TAB Name TAB Type TAB Description #!EF #!N TAB surface TAB 
field or group TAB isosurface #!N TAB - TAB - TAB 
#!EF #!N #!N Functional Details #!N #!N This module computes any 
of the following: #!N #!I0 #!N  #!F-adobe-times-medium-r-normal--18*   #!N #!N #!I30 #!N 
o points (for an input field consisting of lines) #!N #!I30 
#!N o lines (for a surface input field) #!N #!I30 #!N 
o surfaces (for a volumetric input field). #!N #!I0 #!N #!EF 
#!N All positions in the output field are isovalues (i.e., they 
match a specified value or values). #!N #!N The module also 
adds a default color to the output (gray-blue for isosurfaces and 
yellow for contour lines and points) if the input object is 
uncolored. If the object is colored, its colors are interpolated in 
the output object. #!N #!N A "data" component with the same 
value as the input  #!F-adobe-times-bold-r-normal--18*   value #!EF is added to the 
output field. #!N #!N #!I0 #!N #!N #!I0 #!N  #!F-adobe-times-bold-r-normal--18*    #!F-adobe-times-bold-r-normal--18*   
data #!EF #!EF #!I50 #!N is the data object for which 
an isosurface or contour is to be created. #!N #!I0 #!N 
 #!F-adobe-times-bold-r-normal--18*    #!F-adobe-times-bold-r-normal--18*   value #!EF #!EF #!I50 #!N is the isovalue or 
isovalues to be used for computing the isosurface(s) or contour(s). #!N 
#!N If this parameter is not specified, the module bases it 
calculations on the value specified by  #!F-adobe-times-bold-r-normal--18*   number #!EF (see below). 
If neither parameter is specified, the module uses the arithmetic mean 
of the data input as a default. #!N #!I0 #!N  #!F-adobe-times-bold-r-normal--18*   
 #!F-adobe-times-bold-r-normal--18*   number #!EF #!EF #!I50 #!N is ignored if  #!F-adobe-times-bold-r-normal--18*   value 
#!EF has been specified. If that parameter is not specified, the 
module uses the value of  #!F-adobe-times-bold-r-normal--18*   number #!EF to compute a 
set of isosurfaces or contours with the following isovalues: #!CForestGreen #!N 
#!N  #!F-adobe-courier-bold-r-normal--18*   #!N min + delta, min + (2*delta),..., min - 
delta #!EF #!N #!N #!EC where delta = (max - min)/( 
 #!F-adobe-times-bold-r-normal--18*   number #!EF + 1), and "max" and "min" are the 
maximum and minimum data values of the input field. #!N #!I0 
#!N  #!F-adobe-times-bold-r-normal--18*    #!F-adobe-times-bold-r-normal--18*   gradient #!EF #!EF #!I50 #!N is the gradient 
field used to compute normals for shading (see  #!Lgradien,dxall857 h Gradient  #!EL  ). #!N 
#!N If this parameter is not specified, the module adds normals 
by computing the gradient internally (  #!F-adobe-times-bold-r-normal--18*   flag #!EF can nullify 
this behavior; see below). Note: If only one isosurface is to 
be computed, it is probably more efficient to have module compute 
the gradient internally. If many are to be generated, it is 
probably more efficient to compute the gradient of the entire field 
once, so that the system can use it for every isosurface. 
#!N #!I0 #!N  #!F-adobe-times-bold-r-normal--18*    #!F-adobe-times-bold-r-normal--18*   flag #!EF #!EF #!I50 #!N specifies 
whether normals are to be computed for shading. A setting of 
0 (zero) prevents the computation of normals. The default is 1 
(one) #!N #!I0 #!N  #!F-adobe-times-bold-r-normal--18*    #!F-adobe-times-bold-r-normal--18*   direction #!EF #!EF #!I50 #!N 
specifies whether the normals should point against (0, the default) or 
with (1) the gradient. #!I0 #!N #!N #!N #!N #!I0 #!N 
Notes: #!N #!I30 #!N 1. This module adds an attribute called 
"Isosurface value," which has as its value the isovalue(s) used. To 
extract this attribute (e.g., for use in a caption for an 
image), use the Attribute module. #!N #!I30 #!N 2. For contour 
lines, this module adds a "fuzz" attribute so that the line 
will be rendered slightly in front of a coincident surface (see 
 #!Ldisplay,dxall807 h Display  #!EL  ). #!N #!I30 #!N 3. A surface or contour is 
considered to be undefined if every point in the input volume 
or surface, respectively, is equal to  #!F-adobe-times-bold-r-normal--18*   value #!EF . In 
such cases, the module output is an empty field. #!N #!I30 
#!N 4. Isosurface does not accept connection-dependent data. #!N #!I30 #!N 
5. With disjoint data fields, there may be no data crossings 
(i.e., points along a connection element where the interpolated data value 
equals the isovalue), even though the isovalue itself falls in the 
range of the actual data. #!I0 #!N #!N #!N #!N Components 
#!N #!N Creates new "positions" and "connections" components. For surfaces output, 
the default is to create a "normals" component. Any component dependent 
on "positions" is interpolated and placed in the output object. #!N 
#!N Example Visual Programs #!N #!N Many example visual programs use 
the Isosurface module, including: #!CForestGreen #!N #!N  #!F-adobe-courier-bold-r-normal--18*   #!N AlternateVisualizations.net #!N 
ContoursAndCaption.net #!N InvalidData.net #!N MappedIso.net #!N Sealevel.net #!N UsingIsosurface.net #!N SIMPLE/Isosurface.net 
#!EF #!N #!N #!EC #!N #!N See Also #!N #!N  #!Lband,dxall779 h Band  #!EL  
,  #!Lcolor,dxall792 h Color  #!EL  ,  #!Lgradien,dxall857 h Gradient  #!EL  ,  #!Lmap,dxall891 h Map  #!EL  ,  #!Lsimpsur,dxall947 h SimplifySurface  #!EL  #!N #!N #!N 
 #!F-adobe-times-medium-i-normal--18*   Next Topic #!EF #!N #!N  #!Lkeyin,dxall882 h KeyIn  #!EL  #!N  #!F-adobe-times-medium-i-normal--18*   #!N