There are certain file name extensions that plug-in DLLs must use. 3ds Max uses these standard extensions as part of its search algorithm to determine which files it will attempt to load. Below is a list of the extensions and the plug-in types associated with each one:

• BMI - Bitmap Manager IO DLLs.
• BMF - Bitmap Manager Filter plug-ins.
• BMS - Bitmap Manager Storage DLLs.
• DLB - Shader plug-ins.
• DLC - Controllers.
• DLE - Scene Export plug-ins.
• DLF - Font Loaders.
• DLH - Sampler plug-ins
• DLI - Scene Import plug-ins.
• DLK - Filter Kernels (Anti-aliasing filters)
• DLM - Modifiers.
• DLO - Procedural Objects.
• DLR - Renderers.
• DLS - Object Snap plug-ins.
• DLT - Materials and Textures.
• DLU - Utility plug-ins.
• DLV - Rendering Effects
• DLX - MAXScript extension plug-ins.
• FLT - Image Filter plug-ins.
• GUP - Global Utility plug-ins.

Note that it is acceptable to have several different plug-in types present in a single DLL. As long as the DLL uses one of the file name extensions listed above, 3ds Max will load all the plug-ins present. For example, if a developer created a system plug-in using both a procedural object and a controller, they could place them both in the same DLL. 3ds Max would load them all (provided the file name extension matched one of those above).