grammar - How to use ところだった to express time related events

Can someone explain how だった changes the meaning when put after ところ?

From what I understand, ところ can be used to express when an action takes place：

1. するところ　- about to do [verb]

今から家にかえるところだ。I am about to go home.

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2. しているところ - in the middle of doing [verb]

氷が溶けているところです。The ice is in the middle of melting.

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3. したところ - just finished [verb]

今着いたところです。 I just arrived now.

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4. していたところ - was in the middle of doing [verb]

あなたのことを話してたところだよ。I was in the middle of taking about you.

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However I don't understand the nuance or how the meaning changes when だった is put after ところ.

1. するところだった - I understand this to mean "was about to do [verb] (but it didn't happen)"


2. しているところだった


3. したところだった - How is this different from したところ?


4. していたところだった

I would appreciate some example sentences to help me understand the difference between ところ by itself and ところだった

Answer

In my own experience with Japanese-learners, it has always seemed that the construct:

「Verb Form + ところ + だった」

is used incorrectly more often than one would expect. In particular, it has seemed difficult for them to tell whether the action in question actually did or did not take place.

Let us examine the four patterns that you have listed:

1) 「するところだった」 - I understand this to mean "was about to do [verb] (but it didn't happen)"

Precisely. It never happened. This means either it almost happened or it was about to happen. You might have just changed your mind or something unexpected happened that prevented the originally planned action from taking place.

「もう少{すこ}しで電車{でんしゃ}に乗{の}り遅{おく}れるところだった。」 = "I almost missed my train."

The action of 電車に乗り遅れる ("missing the train") did not take place. You were able to catch the train just in the nick of time.

2) 「しているところだった」

You were engaged in an action at the time that is being talked about in the context. You were in the middle of performing that action.

「母{はは}から電話{でんわ}が入{はい}ったとき、ボクは宿題{しゅくだい}をしているところだった。」 = "When my mother called, I was doing my homework."

The tense of the sentence, which is past tense, is expressed properly by 「だった」. That is why using 「している」 is grammatical here as it has no effect on the tense of the sentence as a whole.

3) 「したところだった」

This pattern forms the equivalent of the English pluperfect -- "I had just (performed an action) when X happened." The action had already taken place at the particular time that is being discussed.

「雨{あめ}が降{ふ}り出{だ}したのは、試合{しあい}が始{はじ}まった（ばかりの）ところだった。」 = "It started raining when the game had just started".

How is this different from したところ?

Not too sure what you mean by that, but perhaps you are talking about a sentence like:

「試合が始まったところで雨が降り出した。」, which is also natural and grammatical. It means virtually the same thing as the example sentence above (except for the fact that there is no pluperfect used in this new sentence).

4) 「していたところだった」

This construct expresses the same thing as 2) 「しているところだった」. You will see/hear the two equally often.

Finally,

I would appreciate some example sentences to help me understand the difference between ところ by itself and ところだった

I honestly have no idea what you mean by the difference between ところ by itself and ところだった.

In very informal speech, people say:

「ちょうどアンタの話をしてたところ！」 instead of:

「ちょうどアンタの話をしてたところだったの。」

If this is not what you wanted to know, please elaborate on your question.