Following parameters guide the data reduction:
Data reduction parameters of
Tosca Structure.smooth |
Parameter |
Value |
Description |
Supported by |
GUI-TS.pre |
GUI-TS.smooth |
TExt |
REDUCTION_RATE |
Real value between 0 and 100
Default: 0.3 |
Defines the percent of faces that should be
removed during the data reduction; if set to 0, no data reduction occurs.
If set to 100, the data reduction stops when no faces can be removed
(that is checked using the REDUCTION_ANGLE parameter). |
x |
x |
x |
REDUCTION_ANGLE |
Real value in degrees between 0 and 90 Default: 15 |
Defines the maximal angle between adjacent faces at a node such that the node might be removed during the data reduction. |
x |
x |
x |
MIXED_MESH |
yes (unite triangles to quadrilaterals)
no (no change)
default: no |
If set to YES, then the quadrilaterals are formed from adjacent triangles; applies to VTFX, ONF, and IGES output formats only. |
x |
x |
x |
SELF_INTERSECTION_CHECK |
off (no checks)
check (check once)
runtime (check always)
iterative (first run without check, rerun if required)
Default: iterative |
Defines if the self-intersection checks are to be performed during the isocut, smoothing, and data reduction. See below. |
x |
x |
- |
MIN_ANGLE |
Real value between 0 and 90 Default: 15 |
Defines the minimal angle of the triangles that
result from the smoothing and data reduction; triangles with smaller
angles might be present if they are created during the isocut. Too large
value might prevent the smoothing; too small value may lead to degenerated
triangles. |
- |
x |
- |
The data reduction consists in decreasing the number of surface triangles;
it might be needed in case that the surface is produced from a very fine
FE model or simply has too many faces. The data reduction can be applied
to isosurfaces as well as surfaces of models with or without optimization
displacements. During the data reduction, the adjacent triangles with
nearly coinciding planes get united and subsequently subdivided so that
a triangular surface with smaller number of faces is obtained. This process
is repeated until the decrease of the number of triangles reaches a certain
percentage of the starting number of triangles; this percentage is the
value of the parameter REDUCTION_RATE
. If set to 0 (default),
no data reduction is performed; if set to 100, the data reduction is
repeated until the number of triangles cannot be decreased further. The
conditions that define if a local data reduction can be made are as follows:
- the angle between the normals of adjacent triangles is less than the
value of the
REDUCTION_ANGLE
parameter (default value is 15°);
- the angles of triangles after the reduction are larger than the value
of
MIN_ANGLE
parameter;
- no self-intersection occurs after the reduction (only checked if the
SELF_INTERSECTION_CHECK
parameter is set to iterative
or runtime
).
As seen from the example shown below, in order to achieve maximal data
reduction, the REDUCTION_RATE
parameter should be set to 100 and the
REDUCTION_ANGLE
parameter to a large value (for example, 45). However,
the surface then becomes coarse. By changing the REDUCTION_ANGLE
parameter, the surface with sufficient smoothness and reasonably small
number of triangles can be obtained.
The parameters MIN_ANGLE
and SELF_INTERSECTION_CHECK
usually do not influence the number of triangles remaining after the
data reduction, unless MIN_ANGLE
is set to a large value (30
or more; default value is 15). Note that these parameters are also used
in the surface smoothing.

|

|
REDUCTION_RATE = 0 (default) REDUCTION_ANGLE = 15 (default) 4842 faces (100%) |
REDUCTION_RATE= 100 REDUCTION_ANGLE = 15 (default) |

|

|
REDUCTION_RATE = 50 REDUCTION_ANGLE = 15 (default) 2420 faces (50.0%) |
REDUCTION_RATE = 100 REDUCTION_ANGLE = 45 480 faces (9.9%) |
Data reduction can also be achieved by generating the mixed triangular-quadrilateral
surface. If the parameter MIXED_MESH
is set to yes
,
then the quadrilaterals are formed from adjacent triangles. The triangles
can only be united when the resulting quadrilateral is convex and nondegenerated,
and the angle between the normals of the triangles is smaller than a
certain constant value (currently 15°). An example of using the MIXED_MESH
parameter is presented in the following figure.

|
MIXED_MESH = no (default): 4842 triangles |

|
MIXED_MESH = yes: 2642 triangles, 1100 quadrilaterals |
The generation of the mixed mesh can be combined with the data reduction
described above; it is performed after the data reduction is finished.