O necesitas aprender ingles... sin animo de ofender eh.
De todos modos habeis provado con el source SDK?
http://www.valve-erc.com/srcsdk/prerelease_notes.html
The current SDK release has added these features:
Sources for six Half-Life 2 maps. They can be found under sourcesdk_content\hl2\mapsrc.
XSI addon for importing and exporting SMD files.
[...]
http://www.valve-erc.com/srcsdk/models/compiling_models.html
http://www.valve-erc.com/srcsdk/
http://www.valve-erc.com/srcsdk/general/content_directory_structure.html :
Creating a model for Half-Life 2:
Create a model in Softimage|XSI EXP, and export it as an .SMD in the hl2\modelsrc directory, which is under Content Sources.
Create the .QC model definition file with a text editor, and save it in the hl2\modelsrc directory, which is under Content Sources.
Compile the model with Studiomdl.exe, which is in the SDK Tools Directory.
The model is compiled as a .MDL and automatically placed in the hl2\models Game Content directory.