and select a mesh. The dialog box is displayed:
Select the type of decimation
you want to apply:
Chordal Deviation if you want to preserve the shape of
even in areas with a high curvature,
Length if you want to remove triangles with tiny edges and
a more uniform mesh.
However this may result in a loss of accuracy in areas with a high
Then, decide how you want the decimation to
For a decimation by Chordal Deviation,
you can select the Maximum
check box and type a value.
It is the chordal deviation that should not be exceeded
Decimation stops when the chordal deviation limit has been
For a decimation by Edge Length,
you can select the Minimum check box and type a value.
The command stops when further
decimation could collapse edges of length
greater than the value typed.
For both types of decimation,
Target Percentage check box f
you want to obtain a given final number or percentage of
Type either the percentage value or the
Those fields are linked to each other and updated simultaneously.
Current Triangle Count indicates the current number of
either of the original model when you type the action,
or of the result model when you have clicked Apply.
Decimation with a Chordal Deviation
|Decimation by Edge Length set at 70%:
You may need to control the decimation of free edges, when
a rectangular shape sees its corners
cut off after decimation.
You can avoid this by checking the
This activates the maximum allowable deviation that can occur for vertices
on the boundary.
The resulting decimated boundary will not be at a distance greater than
this parameter from
the original boundary.
The chordal deviation that can be used as a stopping
criterion is an approximation of the chordal
deviation between the original mesh prior to decimation and the decimated
Therefore it may be useful to know the maximum distance and the mean
the original mesh and the result mesh at the end of the command.
To do so, select the
Analysis check box
before clicking Apply.
At the end of the decimation, the maximum and the mean deviation will
be reported as shown below.
Unlike the value typed in the Maximum field, they are the
true deviations between the original mesh
and the result mesh.
- However, Analysis may be time consuming, especially
for large models.
We recommend that you turn it off when you do not need it.
- The meshes can be decimated in several steps (click Apply=
The deviations displayed are those between the original model and
the last result
(not those between the previous and the current results).
For this reason, the deviations will be increasing in value after
- Any selection change resets the original model for the analysis.
- Undo is not taken into account by the Analysis.
Click Apply, a
progress bar is displayed. A Cancel button is available to stop
Click OK to confirm the decimation once you are
satisfied with the result.