This is the "plain text" of the 3D world. It is a simple, non-proprietary format that represents 3D geometry—vertices, textures, and normals—in a way that almost every 3D software (like Blender, 3ds Max, or Maya) can read. The Conversion Process: Step-by-Step
This is a proprietary format used by Rockstar Games' RAGE engine. Unlike a simple 3D model, a YDD file is a "container." It often holds multiple high-detail and low-detail versions of an object (LODs), along with information about how the mesh should behave in a physics engine. ydd to obj converter work
3D models are made of points in space called vertices. In a YDD file, these are stored in "buffers" to save memory. The converter scans these buffers to find the X, Y, and Z coordinates for every point of the model. 3. Mapping UVs and Normals This is the "plain text" of the 3D world