The MAX file type is a complete scene file.
A CHR file is a Character Assembly file saved with Save Character.
A DRF file is a scene file from VIZ Render, a rendering tool included with AutoCAD Architecture (formerly Autodesk Architectural Desktop). The DRF file type is similar to MAX files saved using Autodesk VIZ.
If the file you're loading was created using plug-ins that are not installed, a dialog lists them. You can still load the file, but any entities in the scene that were created by the missing plug-ins are replaced with stand-ins: non-rendering boxes or placeholder modifiers. You can safely delete these from the scene, unless you are sharing the scene with a user who has the plug-ins installed.
If the file you are loading contains bitmaps that cannot be located, a Missing External Files dialog appears. This dialog lets you browse for the missing maps, or continue opening the file without loading them.
Automatic Unit Conversion
When Respect System Units In Files is turned on in the System Unit Scale group of the System Unit Setup dialog, loaded files that have a different scene unit scale display a File Load: Units Mismatch dialog. This dialog lets you rescale the loaded scene to the current scene unit scale, or change the current scene unit scale to match the one in the loaded file. No conversion is done when loading files created in 3ds Max 1.x.
- If you choose to match the units in the loaded file, the System Unit Scale setting in the System Unit Setup dialog is changed to the setting in the scene file.
This is the recommended choice, and it is the default in 3ds Max.
For example, if the current system unit scale is set to 1 unit = 1 inch, and the incoming file was set to 1 unit = 1 foot, a sphere with a radius of 100 feet remains 100 feet.
- If you rescale the file objects, the objects are scaled as if they had been created using the current scene unit scale.
For example, if the current system unit scale is set to 1 unit = 1 inch, and the incoming file was set to 1 unit = 1 foot, a sphere with a radius of 100 feet becomes 1200 inches in radius (assuming the unit display is set to generic units).
If Respect System Units In Files is off (which is not recommended), 3ds Max disregards the units chosen in the loaded scene file.
For example, a 100-unit radius sphere that was created in a 1 unit = 1 foot scene becomes a 100-inch sphere in a 1 unit = 1 inch scene.