3ds Optimize tool

After you have done with your scene select the object that you're going to optimize

Now go to the modifier list and choose the optimize modifier

You can now see the parameter list, and the most important parameters is the face thresh, it is the angle between faces that will be used to

verify if those two faces can become one. I mean if you have two faces linked and between them there is a 30 degree angle, you'll have to

choose a face thresh of 30 to make the two faces become one plane.
To explain the other parameters I'll use the definition from the help of 3dstudio max 9.

Edge Thresh—Sets a different threshold angle for open edges (those that bound only one face). A low value preserves open edges. At the same

time you can apply a high face threshold to get good optimization. Default=1.0.

Bias—Helps eliminate the skinny or degenerate triangles that occur during optimization, which can cause rendering artifacts. Higher values

keeps triangles from becoming degenerate. The default of 0.1 is enough to eliminate the skinniest triangles. Range=0.0 to 1.0 (a 0 value

turns Bias off).

Max Edge Len—Specifies the maximum length, beyond which an edge cannot be stretched when optimized. When Max Edge Len is 0, it has no effect.

Any value greater than 0 specifies the maximum length of the edges. Default=0.0.

Along with Bias, this control helps you avoid creating long skinny faces while optimizing.

Auto Edge—Turns edges on and off following optimization. Turns on any open edges. Turns off any edges between faces whose normals are within

the face threshold; such edges beyond the threshold are not turned on. Default=off.

Well, Now that you have understanded the basics, you should try to experiment a set of values that will match with your needs.

you might want to watch the number of vertices and faces through the status below on the parameter list.