Each model vertex takes 12 bytes. Each model triangle takes 6 bytes. The memory usage for textures is the width, times the height, times (the color depth divided by 8). Animation frames vary more. Vertex animation stores each vertex's positions for every frame so for 1000 vertices and 2000 faces, you'd be using 12000+12000 or 24000 bytes. If you had 100 frames, this becomes 2.4 million bytes. For bones animation, the positions and angles of each bone are stored, 24 bytes per bone.