Cinema 4D is a 3D modeling and animation software developed by Maxon. It is also capable of uploading various, pre-existing models, including 3D game models.
When opening a game model for viewing or animating, be aware that the files displayed aren't recognized by the computer, and attempting to open it through right-clicking doesn't always display the option to view them in Cinema 4D.
The proper way to view the models is to either open them through the C4D itself (Windows), or drag the model file you want to view into the program's icon (Mac).
Some ripped models come with textures pre-installed into the model. But some models are ripped with their textures separate requiring you to upload them into the Material section seen below:
To upload the models, double click on a material, or right click and choose Edit to open the Material Editor box:
Highlight "Color" and click the Ellipses button to open your OS system's file window and locate the textures needed to replace the standard gray material.
You soon notice that the model is shining which, for most models, never shows up in the games they were ripped from. Even if the models come with the texture pre-installed, the shine is still present. This is because Cinema 4D automatically checks "Specular" when a new Material is created.
The problem is easily rectified by either double clicking a material and unchecking Specular, or highlighting all materials used in the model and unchecking Specular on the bottom right corner of the layout.
Be aware that, like any other program designed for 3D viewing or animation, what you download is what will be displayed onscreen. There is no known way of smoothing low-resolution polygons such as PSX, N64, or NDS models, and attempting to do so without properly understanding the mechanics of the software could ruin the original appearance of the models being viewed.