The requirements you must meet to retexture are the following
1. Vampire the Masquerade Bloodlines: You must have the game installed.
2. Quick and Dirty Bloodlines Tools v3.9a build, you can download it here.
3. You must have an image manipulation program such as gimp or photo shop
You can do it in 6 easy steps:
- Extract Files
- Convert Texture
- Editing Textures
- save texture as dds
- convert dds to ttz and tth
- copy files into right location, and test
for a detailed description please go here: Gamemodscore.org