Action3D Reducer is a great polygon reduction tool that changes the level of detail in real-time and creates both .3ds and .x files. This is the demo version which is save-disabled.
To reduce a 3d object, Reducer creates a progressive mesh. You can reduce and increase the number of triangles displayed by a progressive mesh in real-time using a slider control. You can also display a progressive mesh with the lowest triangles count for the selected level of details and of quality. You have total control on the reduction parameters although the default setting works fine. Reducer can reduce big models and was tested with 3D objects containing up to 300 000 triangles.
This is a user-friendly button driven desktop application. You can create multiple documents and each document is a virtual world in which you can move like in a first-person shooter game, pick and rotate the 3d objects with your mouse. To make it easier to inspect your 3d objects, you can enable up to 6 directional lights, change the light and the background color.
You can load 3d objects from a .3ds and .x file and save them in either file formats. Action3D Reducer can also load the following texture file formats: .bmp, .dds, .dib, .jpg, .png, and .tga.
Not all models can be reduced by a factor of 10 while keeping a decent level of quality. Obviously, it depends on the density of the original model and its geometry. But Action3D Reducer is a real polygon cruncher and you will have a hard time to find a competing product that can reduce further a 3d object reduced with Action3D Reducer without a great loss in quality.
If you want a small foot-print for your 3D objects while still looking good, Action3D Reducer is the right tool for you.