This tool is mostly obsolete. Use HLAM instead. It can do almost everything this program can, and works with more models.

https://github.com/Solokiller/HL_Tools/releases

modelguy

This tool modifies Half-Life models without decompiling them.

Usage:
modelguy <command> <parameters> <input.mdl> [output.mdl]

Commands

• merge - Merges external texture and sequence models into the output model. If no output file is specified, the external models will also be deleted.
• crop - Crops a texture to the specified dimensions. Used after compiling model. Takes <width>x<height> as parameters.
• rename - Renames a texture. Takes <old name> <new name> as parameters.
• info - Write model info to a JSON file. Takes <input.mdl> <output.json> as parameters.

Examples:
modelguy merge barney.mdl
modelguy crop face.bmp 100x80 hgrunt.mdl
modelguy rename hev_arm.bmp Remap1_000_255_255.bmp v_shotgun.mdl
modelguy info barney.mdl barney.json