Meaning of ~を~に(して) / ~を~として / ~を~にする / ~を~とする / ~を~にした / ~を~とした


While studying I found this grammar form, which I kinda understand by
instinct, but can't actually formalize in my head; this is what the book say:

> [~を~であると考えて]
>
> 1) 祖父は今日も孫のヒロシを話し相手 **にして** 散歩に出かけた。
>
> 2) 今回のキャンプを最後に、わたしたちのグループは解散することになった。
>
> 3) 卒業を1つの区切り **として** 、これからは自立して生きていきたい。
>
> 4) この大会に参加できるのは社会奉仕を目的 **とする** 団体だけです。
>
> 5) この研究会では環境問題を中心 **とした** さまざまな問題を話し合いたいと思う。
>
> 「N1をN2にして」という形で、ある行動や場面において、N1はN2であると言いたいときの表現。

I think I kinda get the general meaning:

> 1) 祖父は今日も孫のヒロシを話し相手 **にして** 散歩に出かけた。
>
> Today Hiroshi's grandfather went out walking again with is grandchild
> Hiroshi as speaking partner [something like they speak while they walk, I
> guess?]
>
> 2) 今回のキャンプを最後に、わたしたちのグループは解散することになった。
>
> It was decided that at the end of this camp our group would be dispersed
>
> 3) 卒業を1つの区切り **として** 、これからは自立して生きていきたい。
>
> As one of the end of graduation, I want to be able to live indipendently
> from now on
>
> 4) この大会に参加できるのは社会奉仕を目的とする団体だけです。
>
> Only associations working in the voluntary social services can attend this
> assembly
>
> 5) この研究会では環境問題を中心 **とした** さまざまな問題を話し合いたいと思う。
>
> In this seminar, whose focus are enviromental issues, I wat to discuss many
> issues

My problem is, I can't formalize this in my head, and my Japanese is failing
me in clearly understanding the book's explanation (`[~を~であると考えて]` and
`「N1をN2にして」という形で、ある行動や場面において、N1はN2であると言いたいときの表現`); it seems to mean "N1 is
N2", but then again I'm not sure about the sentences:

> 祖父は今日も孫のヒロシを話し相手にとして散歩に出かけた

This seems to be `祖父はN1をN2として`, whith N1 = `孫のヒロシ` and N2 = `話し相手`; so... the
grandchild is the speaking partner? And the sentence means something like "As
for the grandfather [祖父は], he went out to take a walk [散歩に出かけた] with his
grandchild as speaking partner [孫のヒロシを話し相手にとして]"? Is in て-form because after
the sentence continues, while `とする` would be used if the sentence ended?

If I were to asnwer to the question "Ok, but what does it mean?" I'd be
confused explaining; it's kinds "N1 as N2", "N1 is N2", but I'm not sure
that's all there is. The second sentence is proving particulary difficult to
fit in this framework:

> 2) 今回のキャンプを最後に、わたしたちのグループは解散することになった。

N1 = `今回のキャンプ`, N2 = `最後(に)`? Or does N2 comprise something more? I can't fit
it in "N1 is N2" frame no matter how I parse it.

I also found [this](https://japanese.stackexchange.com/questions/18593/what-
is-the-difference-
between-%E3%82%92-%E3%81%A8%E3%81%99%E3%82%8B-and-%E3%82%92-%E3%81%A8%E3%81%97%E3%81%9F-before-
nouns) question, which kinds seems to confirm my intuition, but it doesn't
really help in formalizing it.

Edit: the book explains all the forms in the title with the same examples and
explanation, hence this question's title; not sure about any difference among
those forms.




Most of the time, you can think of the "AをBに(して)" construction as "with A as
B", "with A at/in B", or "thinking/making/using A as B". This has been asked
many times, so please take a look at [these
questions](https://japanese.stackexchange.com/questions/linked/20854?lq=1)
linked to [this](https://japanese.stackexchange.com/q/20854/5010). AをBにする and
AをBとする are usually interchangeable, but for the subtle difference, see
[とする・にする before a noun](https://japanese.stackexchange.com/q/33722/5010)

  * 孫のヒロシを話し相手に  
= 孫のヒロシを話し相手にして  
= 孫のヒロシを話し相手として  
with his grandson Hiroshi as his chat partner (にとして must be a typo.)

  * 卒業を1つの区切りに  
= 卒業を1つの区切りにして  
= 卒業を1つの区切りとして  
with/making this graduation as a turning point (of my life)

  * 今日のキャンプを最後に  
= 今日のキャンプを最後にして  
= 今日のキャンプを最後として  
with/thinking/making this camp as the last one

These are adverbial (i.e., verb-modifying) expressions, but "AをB{と/に}{した/する}"
forms attributive (i.e., noun-modifying) expressions as relative clauses.

  * 社会奉仕を目的に(して)  
with social services as the purpose  
→ for the purpose of social services

  * 社会奉仕を目的{にする/にした/とする/とした}団体  
organizations for social services

  * 環境問題を中心に(して)  
with environmental problems as the core  
→ focusing on environmental problems

  * 環境問題を中心{にする/にした/とする/とした}さまざまな問題  
various issues around environmental problems




Most of the time, you can think of the "AをBに(して)" construction as "with A as
B", "with A at/in B", or "thinking/making/using A as B". This has been asked
many times, so please take a look at [these
questions](https://japanese.stackexchange.com/questions/linked/20854?lq=1)
linked to [this](https://japanese.stackexchange.com/q/20854/5010). AをBにする and
AをBとする are usually interchangeable, but for the subtle difference, see
[とする・にする before a noun](https://japanese.stackexchange.com/q/33722/5010)

  * 孫のヒロシを話し相手に  
= 孫のヒロシを話し相手にして  
= 孫のヒロシを話し相手として  
with his grandson Hiroshi as his chat partner (にとして must be a typo.)

  * 卒業を1つの区切りに  
= 卒業を1つの区切りにして  
= 卒業を1つの区切りとして  
with/making this graduation as a turning point (of my life)

  * 今日のキャンプを最後に  
= 今日のキャンプを最後にして  
= 今日のキャンプを最後として  
with/thinking/making this camp as the last one

These are adverbial (i.e., verb-modifying) expressions, but "AをB{と/に}{した/する}"
forms attributive (i.e., noun-modifying) expressions as relative clauses.

  * 社会奉仕を目的に(して)  
with social services as the purpose  
→ for the purpose of social services

  * 社会奉仕を目的{にする/にした/とする/とした}団体  
organizations for social services

  * 環境問題を中心に(して)  
with environmental problems as the core  
→ focusing on environmental problems

  * 環境問題を中心{にする/にした/とする/とした}さまざまな問題  
various issues around environmental problems

