Well - that was intentional. The design assumes that we are staying in a specific space - inside a given file / workspace. Importing then is bringing sth in (from out of blender-specific space), while exporting is dispatching it out (to a foreign environment).
Design is very synthetic and uses the assumption that the user reads from left to right, which is not obvious. A possible improvement would be to add an anchor point that specifies "from" and "to".

So logically, on the theory of reading left to right, you have in left and out left when it should be in left, out right.

@Lin Fo - nope. Now "in" comes from left to right, while "out" goes from right to left.
Anyway, will try to make different design.

I really don't see what the issue is here, current icons are perfectly fine.
Either way it is quite irrelevant, direction is completely arbitrary.
I don't think there is any convention for this, both would be explicit as long as it follows some logic.

If this causes confusion perhaps something along these lines (please excuse crude mockup), once again directions could be flipped.

Also included a possible alternative for the save icon.

BTW congrats to @Andrzej Ambroz (jendrzych) for the fantastic work on the icons. Some still need some tweaking, but overall it is fantastic work. Goes a long way in modernizing the appearance of Blender

I also stumbled over this particular topic a few days ago.

Maybe the idea left-in right-out comes from a timeline/workflow analogy ...

Also think of some everyday icons... like Arrival/Departure or upload/download etc...

Just my 2 cents :)

In T58167#565630, @Andrzej Ambroz (jendrzych) wrote:

I still prefer simplicity of current design, though.

Agree, but those are also quite acceptable. I'd go with either the left most or the right most family

Some more doodles:

I'll go with first from the left, since its the most common set of symbols used for import/export.

All these look great, I particularly like the first and third set
The straight up and down arrows may look like download/upload or save icons though, so I think the third set with "Bent Arrows" would be the way to go.

Thumbs up from me for the third one as well:)

For my perception it goes nicely with "coming in" from the left and "going out" to the right which is what i believe is a very common way to look at it. Well, at least i am used to look at things like this.

I think the third one is perfect :)

Well - third one seems to be ok, but after a while I find it tad too busy. The first one still is the best one, with vertical symmetry, similar silhouette and clearly underlined in/out depiction. If You don't like it, the second best is fourth then (by my mind, of course).

I fiddled a bit with your proposal...

@ Andrzej -If you swapped the 1st vertical arrows to Down on the Left and Up on the Right, then I think it's more understandable.
Import/Down/In, Export/Up/Out

Import/Down/In, Export/Up/Out - of course it is designed like that! I was so focused on making sketches and so fixed with the in/down - out/up concept, that I didn't notice the fact that icons are flipped. Sorry for confusion.