Having the same issue when trying to add window open/close animation to an existing truck model. The steps i perform:
1. Import interior and anim models (model.pmg and anim.pmg) into blender
2. Find windows piece in model.pmg and copy it.
3. Edit windows piece to remove side windows from model.pmg
4. Edit copied windows piece to only keep side windows. Assign this piece to anim.pmg (relations -> parent)
5. Perform all of animation work (create vertex groups, assign vertices to groups, create animations, add bones, create animation actions, assign everything to correct places, etc)
6. Test if animations work in blender (they do)
7. Check if everything is in correct places in blender (they are)
8. Set correct paths for exporting (/vehicle/truck/xxx/interior so the collision file is found)
9. Export everything successfully. No errors or warnings are shown in blender
10. Move exported files to Conversion Tools' base dir (it being empty)
11. Clear @cache folder of Conversion Tools
12. Run conversion. Everything is converted successfully, no errors or warnings are present in console or logs.
13. Pack converted file into .scs
14. Start game, go to dealer, check interior.
Everything from here is just a mess. All of animated models are out of place (steering wheel being outside of truck interior, sideways, for example). It seems as if the animated models are not attached to their correct position any longer. But i cannot pinpoint to what is causing this issue. Everything goes smootly, from adding thigs, animating them to exporting and converting.
Game log shows no errors or warning. No crashes are present during truck customization or driving.
Can anyone give me some clues as to what am i doing wrong?
Edit: My added animation now seems to be working correctly, however existing old ones are still messed up...
Edit2: As per this thread viewtopic.php?f=159&t=283144
it seems that when importing interior animations model (*.pmd) for editing in blender, all related animations (*.pma) must also be imported, otherwise after exporting, old animations will no longer work. I will try to do just that tomorrow and will report the results.
Edit3: Indeed, importing all .pma files along with anim.pmg, adding new animations and exporting everything solved all of my problems with animations. Everything is at the right place, working correctly. Hopefully someone will find this helpful.