You require DOOM to DOOM 3 Map Converter (1.4) software (written by redM) to perform actual map/textures conversion.
Download it at first and extract at this front-end's install folder.
You also read the README of DOOM to DOOM 3 Map Converter carefully.
Required to configure every time you launch this front-end. Fill DOOM3 installation folder and select MOD folder.
Copy wad file to converter folder
You have to have at least one of following retail package of Doom software, then copy your main wad file to converter folder:
Build texture pk4 package from wad file. Proceed this section every new release of map converter.
Copy pk4 package files to your Doom 3 installation
Copy the required pk4 package to your Doom 3 base or MOD folder.
Convert your custom Doom map or original map to Doom 3 map format. Proceed this section every new release of map converter.
The following actions in one step:
Copy map file to Doom 3 base or MOD folder.
Formalize map file so that Doom 3 bsp compiler performs for it.
Auto map compile by Doom 3 bsp compiler.
Auto map launching after compiling.
DOOM -> DOOM3 Map Converter written by Michael
Stokes and redM
Unofficial GUI front-end for DtoD3 converter and Cleanqm written
by kentaro-k.21