Is there a relationship between ~たところで and するところだった?


I am studying an JLPT book on listening, and in two questions very close to
each other, the grammatical forms `~たところで` and `するところだった` came up.

My book defines `~たところで` as giving an impression of giving up because
something is perceived to be impossible. An example they give is:

> 走{はし}ったところで...

My rough translation is, "(we won't make it) even if we run."

My book defines `するところだった` as meaning something was intended, but it did not
happen. An example they provide is:

> 危{あや}うく、だまされるところだった。

My approximate translation is, "that was close - we were almost tricked."

Both mean something won't happen in spite of intention...?

This sentence came up in a question:

> お伝{つた}えするのを忘{わす}れるところでした。

And apparently it means that the speaker did not forget to tell someone
something.

First, I got a little confused about which of the above two variations on
`ところ` was being used, but either way, it seems like it's saying the person did
not forget in spite of intending to. Intending to forget something seems a
little weird, though, so I think something isn't adding up.

Am I right that `~たところで` and `するところだった` are similar in meaning? Do they have
anything to do with intention? And does `忘{わす}れるところでした` have anything to do
with intending to forget?




I understand `~たところで` as "even if you try ... it's not possible that...". As
such, I don't think it's really about intention, it's more about an impossible
situation (though maybe it can be argued that the impossible outcome is the
intention).

Your sentence might be finished with 「もう間に合わない」- making it on time is not
possible despite the effort:

> 走ったところで、もう間に合わない。 (Even if we run, we won't make it on time).

* * *

As for `するところだった`, I understand it as "something almost happen/didn't happen,
it was close". It's often used with phrases like
「もうちょっとで」,「もう少しで」,「[危]{あや}うく([危]{あぶ}なく)」 to show that it was really close to
something happening or not happening. There may be intention involved but it's
not the focus of this structure and sometimes the intention may be less clear.
Examples might be:

> もう少しで乗り遅れるところだった。  
>  I almost missed the train. (It was my intention to board that train.)
>
> もう少しで階段から落ちるところだった。  
>  I almost fell down the stairs. (Here the intention is less clear. People
> generally don't want to fall down the stairs but it's a rather "passive"
> intention.)

In the case of your sentence, I understand it as:

> お伝えするのを忘れるところでした。  
>  I almost forgot to pass the message. (I wanted to do it. I almost forgot
> but I just remembered.)




I understand `~たところで` as "even if you try ... it's not possible that...". As
such, I don't think it's really about intention, it's more about an impossible
situation (though maybe it can be argued that the impossible outcome is the
intention).

Your sentence might be finished with 「もう間に合わない」- making it on time is not
possible despite the effort:

> 走ったところで、もう間に合わない。 (Even if we run, we won't make it on time).

* * *

As for `するところだった`, I understand it as "something almost happen/didn't happen,
it was close". It's often used with phrases like
「もうちょっとで」,「もう少しで」,「[危]{あや}うく([危]{あぶ}なく)」 to show that it was really close to
something happening or not happening. There may be intention involved but it's
not the focus of this structure and sometimes the intention may be less clear.
Examples might be:

> もう少しで乗り遅れるところだった。  
>  I almost missed the train. (It was my intention to board that train.)
>
> もう少しで階段から落ちるところだった。  
>  I almost fell down the stairs. (Here the intention is less clear. People
> generally don't want to fall down the stairs but it's a rather "passive"
> intention.)

In the case of your sentence, I understand it as:

> お伝えするのを忘れるところでした。  
>  I almost forgot to pass the message. (I wanted to do it. I almost forgot
> but I just remembered.)

