Polygon Reduction Editor
on this page: how it works | tips for best results | tips
for creating LODs
Find it: Click its button on the Editors palette: 
Use to:
-
Reduce polygon count of an object or group of objects in your scene,
while keeping the shape's integrity.
-
Create multiple Levels of Detail for an
object.

Click image for full view.
Viewing Your Edits
Click Viewing to see your reductions in the editor's preview
window. This window is an Examiner Viewer
with its controls hidden. Use Alt-drag to adjust the object in
the preview window.
Use the sliders to experiment with different types of polygon
reduction. Also see Tips for Best Results.
-
Delete Points by Curvature: Deletes points and re-triangulates the
shape to compensate for lost points. Measures the dihedral angle
between each adjacent pair of
triangles and removes those triangle pairs that have a common dihedral
angle less than the value you specify with slider. 0-90 corresponds to
the degree of dihedral angles.
-
Discard Triangles by Area: Finds the area of triangles in
the object and gets rid of the smallest triangles. Move the slider to
adjust the area of the triangles that are discarded.
-
Discard Edges by Length: Calculates the lengths of all edges
of the object and discards the smallest. Move the slider to adjust the
value of the edges that are discarded.
-
Merge Initial Coordinates: Merges nearby points into a
single point if they are within a certain distance of each other. Move
the slider to adjust the distance at which nearby points are merged.
-
Play with the different sliders to see which combinations yield the
best result. To start, try the Discard Edges by Length slider
with Conserve Surface Edge selected. This pair reduces many
polygons while keeping the original shape of the object.
-
Try sliding a bar a little bit, clicking Accept, and
repeating--this incremental reduction can work well with some objects.
You can always undo mistakes in the main scene with Ctrl-z.
-
If you find a slider combination that gives you a pretty good result
except for a few points, turn on Lock/Unlock Points then
click points to specify those that should not disappear when you reset
the slider. You can toggle on and off the markers for
Lock/Unlock Points by clicking Display Lock Markers. It
is often useful to work in hidden line or wireframe mode while choosing
points to lock (Popup Menu > Display).

Polygon reduction with Lock/Unlock Points. Notice the red
cross-hairs in the scene. These move with your mouse cursor to help you
identify and select the correct points you want to lock. Locked points
appear as light-blue Xs.
-
Instead of Lock/Unlock Points, you can first try Conserve
Surface Edges. This helps keep the object's original shape intact when
you reduce it. Sometimes holes may appear; if this happens, using Lock/Unlock
Points gives you a better result.
-
Create a new file for each LOD, then specify its use in your scene by
using the Level of Detail Editor.
-
When working in the Polygon Reduction Editor, periodically adjust your
view of the model at the range the LOD object will be viewed. This
helps you gauge how much detail you really need.
-
Use Octahedron or Bbox for the lowest level of
detail. Use the sliders for LODs that will be viewed more closely.
Jump to: