Revision: 78006
http://sourceforge.net/p/brlcad/code/78006
Author: starseeker
Date: 2020-12-18 20:24:20 +0000 (Fri, 18 Dec 2020)
Log Message:
-----------
Update facetize man page with examples showing the use of the
decimation-feature-size option in CM mode.
Modified Paths:
--------------
brlcad/trunk/NEWS
brlcad/trunk/doc/docbook/system/mann/facetize.xml
Modified: brlcad/trunk/NEWS
===================================================================
--- brlcad/trunk/NEWS 2020-12-18 19:57:27 UTC (rev 78005)
+++ brlcad/trunk/NEWS 2020-12-18 20:24:20 UTC (rev 78006)
@@ -13,6 +13,7 @@
--- 2020-xx-xx Release 7.32.2 ---
----------------------------------------------------------------------
+* added decimation control examples to facetize man page - Cliff Yapp
* changed gcv converter to append to existing .g files - Cliff Yapp
* added a '-f' forcing option to MGED's quit command - Cliff Yapp
* changed MGED's quit command to wait for subprocesses - Cliff Yapp
Modified: brlcad/trunk/doc/docbook/system/mann/facetize.xml
===================================================================
--- brlcad/trunk/doc/docbook/system/mann/facetize.xml 2020-12-18 19:57:27 UTC
(rev 78005)
+++ brlcad/trunk/doc/docbook/system/mann/facetize.xml 2020-12-18 20:24:20 UTC
(rev 78006)
@@ -148,6 +148,41 @@
</para>
</example>
+
+ <example>
+ <title>Increase Decimation in CM Mode</title>
+ <para>
+ <prompt>mged> </prompt><userinput>facetize --CM --feature-size 0.06
--decimation-feature-size 2.0 ellipse.r ell.bot</userinput>
+ <literallayout class="normal">
+CM: completed in 16 seconds with size 0.06
+CM: completed in 23 seconds with size 0.054
+CM: timed out after 30 seconds with size 0.0486
+CM: successfully created 6960500 faces, feature size 0.054
+CM: decimation succeeded, final BoT has 104 faces
+ </literallayout>
+ </para>
+ <para>
+ The default settings on this object in CM mode will produce a little
over 8000 faces in the final bot, but the addition of the
<option>decimation-feature-size</option> option with a >1.5 value has
dramatically reduced the count to 104.
+ </para>
+ </example>
+
+ <example>
+ <title>Decrease Decimation in CM Mode</title>
+ <para>
+ <prompt>mged> </prompt><userinput>facetize --CM --feature-size 0.06
--decimation-feature-size .01 ellipse.r ell.bot</userinput>
+ <literallayout class="normal">
+CM: completed in 16 seconds with size 0.06
+CM: completed in 23 seconds with size 0.054
+CM: timed out after 30 seconds with size 0.0486
+CM: successfully created 6960500 faces, feature size 0.054
+CM: decimation succeeded, final BoT has 247642 faces
+ </literallayout>
+ </para>
+ <para>
+ If the intent is preserve a more detailed mesh, reducing
<option>decimation-feature-size</option> will keep more of the original
triangles - in the above example, almost 250 thousand of the original 6.9
million faces were retained. NOTE: use lower values here cautiously, as
extremely large meshes can be very difficult for many tools to deal with.
+ </para>
+ </example>
+
</refsection>
<refsection xml:id="methodology">
@@ -193,7 +228,10 @@
process its initial mesh with a decimation routine to remove triangles
which are not necessary to actual
feature representation. This process is also feature-size based, and by
default is set to 1.5x the feature size.
However, if the user wishes to preserve more triangles than the default
behavior they may manually
- override this parameter with the
<emphasis>--decimation-feature-size</emphasis> option.
+ override this parameter with the
<emphasis>--decimation-feature-size</emphasis> option. Generally
+ speaking smaller values will lead to more meshes being retained in the
final output mesh, but experimentation
+ will likely be needed to zero in on desired results. See CM examples
above for an illustration using
+ the moss.g ellipsoid region.
</para>
<para>
Both NMG and CM assume a geometry hierarchy containing only
@@ -215,6 +253,9 @@
</para>
</refsection>
+
+
+
<refsection xml:id="util">
<title>USEFUL TRICKS</title>
<para>
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