>Can I use the $sequence or $animation via a lua script in order to make it animated by pressing 'use' on it in game for example?

Yes.

So if you tell that in model viewer it works, then everything ok.

Not working ingame depends on what you willing to use the model for. For weapon you need to additionally program lua which tells how to play these animations.

For mapping, you place it as prop_dynamic and specify which animation to play.

More context please

Yes

If it's smd/vta, add some lines in flexfile block in $model like:


for dmx, in export table in Flex Properties set it to Simple

See NLA tracks, possibly long one slipped into

Początkowo opublikowane przez R.A:

Then how do I save the animation in sfm correctly in order to transfer it to blender?

IIRC there's dedicated option to export scene as animation (or export for specific object). You would then import the animation while the model armature is selected

The dmx file you want to import is not valid model or animation

This is intended. Sources use 1 unit dimension as 1 inch

Also, it's wrong. Should probably be //my_sword

The folder you export to is not allowed for user account

Nope