View source for How to add new models

First you need a model which is in .md2; .md3; .md5 or .obj format. 
Then make some folders so the final result is like this: 
"Platinum arts sandbox/my stuff/packages/models"
then make a folder which has the name you want into models folder.
for example: "Platinum arts sandbox 2.4/my stuff/packages/models/human"
Then you need to copy your model and its skin into your model folder (in current case human).
then rename the model file to tris (if its a md3 file then tris.md3 and so on)
now place your texture into the same folder.
rename the texture file to skin (if its a png file then skin.png).
now you need a configuration file.
create a text document and rename it to your model format .cfg (for example md3.cfg).
if you are using .md3 then write the following into the .cfg file:
md3load tris.md3
md3skin skin.png
now open up sandbox.
create a new map.
write the following into command line while being in editmode:
mmodel your models location
in current case: mmodel human
now press f1 and the last model on the list should be your model.

Tutorial by Siimvuss