Raf ünitesi hacim hesabına göre seçildi.

Because raf ünitesi is a Turkish noun compound.

• raf = shelf
• ünite = unit
• raf ünitesi = shelf unit / shelving unit

In this kind of compound, the second noun usually takes the 3rd person possessive ending:

• ünite → ünitesi

This does not necessarily mean his/her/its unit in English. In compounds, this ending is just part of the normal structure.

Compare:

• okul kapısı = school gate
• araba kapısı = car door
• raf ünitesi = shelving unit

So ünitesi here is grammatical compound marking, not a separate possessive meaning like the shelf’s unit.

-A göre means according to, based on, or in accordance with.

Here:

• hesabına = to its calculation / according to the calculation
• göre = according to

Together:

• hacim hesabına göre = according to the volume calculation

The word göre requires the noun before it to be in the dative case:

• hesabı → hesabına

So this pattern is very common:

• plana göre = according to the plan
• kurallara göre = according to the rules
• ihtiyaca göre = according to need

There are two things happening here.

First, hacim hesabı is another noun compound:

• hacim = volume
• hesap = calculation
• hacim hesabı = volume calculation

As with raf ünitesi, the second noun gets the compound ending:

• hesap → hesabı

Second, because of göre, this noun has to be in the dative case:

• hesabı → hesabına

That -n- is a buffer consonant used before case endings after this kind of possessive/compound form.

So the steps are:

• hesap
• hacim hesabı
• hacim hesabına göre

Yes. seçildi is the passive past form of seçmek (to choose / select).

Breakdown:

• seç- = choose/select
• -il- = passive marker
• -di = past tense

So:

• seçti = he/she/it chose
• seçildi = it was chosen / it was selected

In this sentence, Raf ünitesi is the thing being selected, so the passive is natural:

• Raf ünitesi ... seçildi. = The shelving unit was selected ...

Turkish does not normally use articles like the or a/an the way English does.

So:

• raf ünitesi can mean the shelving unit, a shelving unit, or just shelving unit, depending on context.

In this sentence, English usually translates it as the shelving unit because the context probably makes it specific.

This is very normal in Turkish. You often understand definiteness from context rather than from a separate word.

The sentence follows a very typical Turkish pattern: the verb comes at the end.

Structure:

• Raf ünitesi = subject
• hacim hesabına göre = adverbial phrase (according to the volume calculation)
• seçildi = verb

So the order is roughly:

Subject + modifier phrase + verb

Turkish often places important descriptive information before the final verb.

English:

• The shelving unit was selected according to the volume calculation.

Turkish:

• Raf ünitesi hacim hesabına göre seçildi.

Yes, Turkish word order is fairly flexible, although the verb usually stays at the end.

For example, you could also say:

• Hacim hesabına göre raf ünitesi seçildi.

This puts more emphasis on according to the volume calculation.

Both are grammatical, but the original sentence sounds neutral and natural.

In Turkish, changing the order often changes focus or emphasis, not the core meaning.

Yes. Raf ünitesi is the subject of the sentence.

In a passive sentence like this, the thing affected by the action becomes the grammatical subject:

• Raf ünitesi ... seçildi.
• The shelving unit ... was selected.

Turkish does not need a special marker here because the subject is in its basic form.

If it were a direct object in an active sentence, you might see a different structure, for example:

• Raf ünitesini seçtiler. = They selected the shelving unit.

There, raf ünitesini has the accusative ending because it is the object.

Seçildi is in the simple past tense.

So it means:

• was selected
• got selected (depending on context)

This is a completed action in the past.

Breakdown:

• -di = past tense marker

Examples:

• geldi = came
• yazıldı = was written
• seçildi = was selected

The sentence does not say who did the action because it uses the passive.

That is one of the main uses of the passive in Turkish, just as in English:

• when the doer is unknown
• when the doer is unimportant
• when the focus is on the result or the thing affected

So:

• Raf ünitesi hacim hesabına göre seçildi. focuses on the shelving unit and the basis for choosing it, not on the person or people who chose it.

If you wanted to name the doer, Turkish would normally switch to an active sentence instead.

Yes. Hacim hesabı is a normal technical or practical expression meaning volume calculation.

It works like many Turkish noun compounds:

• maliyet hesabı = cost calculation
• alan hesabı = area calculation
• zaman hesabı = time calculation

So hacim hesabına göre naturally means according to the volume calculation or based on volume calculations.

An active version would name the person or group doing the selecting. For example:

• Mühendisler raf ünitesini hacim hesabına göre seçti.
• The engineers selected the shelving unit according to the volume calculation.

Compare:

Passive:

• Raf ünitesi hacim hesabına göre seçildi.
• focus on the shelving unit

Active:

• Mühendisler raf ünitesini hacim hesabına göre seçti.
• focus on who selected it

Notice that in the active sentence:

• raf ünitesi becomes raf ünitesini because it is now the direct object.