SUBTOPICS Formats File IO for 3D objects. Advanced classes: DPITriFileC Tri file IO. DPOTriFileC Tri file IO. DPIMeshObjC Tri file IO. DPOMeshObjC Tri file IO. Develop classes: DPITriFileBodyC Tri file IO. DPOTriFileBodyC Tri file IO. DPIMeshObjBodyC Tri file IO. DPOMeshObjBodyC Tri file IO.