To reduce the polygon count in Cinema 4D:
1. Open your 3D model in the viewport and display the number of polygons by selecting the “Objects” in the menu on the right hand side and choosing “Object information”.
2. This will display the number of polygon in your objects (or in your scene).
3. To Reduce the polygon, select the “Bend” tool on the toolbar then “Polygon Reduction”.
4. A “Polygon Reduction” object will be added in the object list on the left hand side. You can then edit the “Polygon Reduction object” to set the reduction percentage.
5. Slide the “Polygon Reduction” object onto the object that you want to decimate. Doing so will automatically reduce the polygons by the percentage you set. After reducing the polygons, check their count as in step 1 right above.