Decompile a model from L4D2 using Crowbar and you'll have the necessary files for it.
NOTE: Some animations may not work properly as the decompiler ain't fully finished yet.
If the above mentioned method ain't working properly for you, try getting the default survivor / weapon's files from C:\Program Files (x86)\Steam\steamapps\common\Left 4 Dead 2\sdk_content. They are in the .dmx format mostly (the animations), but Blender can open those so far I am informed.
Friend, please help me. In my "C: \ Program Files (x86) \ Steam \ steamapps \ common \ Left 4 Dead 2 \ sdk_content" folder has no .dmx files only has the files shown in the image === >> http://prntscr.Com/d9otvhI
I did the following: I extracted the file "pak01_dir.vpk" from the "C: \ Program Files (x86) \ Steam \ steamapps \ common \ Left 4 Dead 2 \ left4dead2" folder to my desktop and got the "decompiled 0.36" folder inside it I got the files shown in the images === >> http://prnt.sc/d9ovge and http://prntscr.com/d9ovya But I can not open any of the animations (.SMD files) but the models I can load.
I have tried to load the model and then the animation, but do not succeed. I will thank you very much if you can help me.
Errors with animations .smd file === >> http://prntscr.com/d9oy4q and http://prntscr.com/d9oyft
Successful loading model ===>> http://prntscr.com/d9oxs6
Thank you for having responded and for your attention, thank you very much.