Выкройка нужна, чтобы кроить ткань.

Выкройка means a pattern in the sewing/clothing sense: a paper template or model used to cut fabric into the right shapes.

It does not mean just any pattern or design. For a visual pattern on fabric, Russian would use other words, such as узор or рисунок.

Because выкройка is a feminine singular noun, and нужна agrees with it.

The short-form adjective changes by gender and number:

• нужен — masculine
• нужна — feminine
• нужно — neuter
• нужны — plural

So:

• Выкройка нужна. — A pattern is needed.
• Нож нужен. — A knife is needed.
• Платье нужно. — A dress is needed.
• Ножницы нужны. — Scissors are needed.

Not exactly. Нужна is the short form of the adjective нужный (necessary / needed).

In Russian, short-form adjectives are often used like predicates:

• Книга интересна. — The book is interesting.
• Помощь нужна. — Help is needed.

So in Выкройка нужна, Russian does not use a separate present-tense verb like is. The idea of is is simply understood.

Here чтобы means in order to or so that.

It introduces a purpose clause:

• Выкройка нужна, чтобы кроить ткань.
• Literally: A pattern is needed, in order to cut fabric.

This is a very common structure in Russian:

• Мне нужен словарь, чтобы читать эту книгу. — I need a dictionary to read this book.
• Мы пришли рано, чтобы всё подготовить. — We came early to prepare everything.

Because after чтобы in this kind of sentence, Russian often uses the infinitive to express purpose, especially when the subject is general or not explicitly stated.

So:

• чтобы кроить ткань = in order to cut fabric

This works much like English to cut fabric.

You could also have a finite verb after чтобы if the clause has its own subject or a more fully developed action:

• Я взял выкройку, чтобы скроить платье. — I took the pattern to make/cut out a dress.

But in your sentence, the infinitive is natural and simple.

Because кроить is a more specific sewing/tailoring verb.

• резать = to cut, in a general sense
• кроить = to cut fabric according to a pattern; to cut out garment pieces

So кроить ткань means something like to cut fabric for sewing, not just to slice fabric with scissors.

That is why выкройка and кроить fit together naturally: a pattern is used specifically for this kind of cutting.

Ткань is the direct object of кроить, so it is in the accusative case.

However, for this noun, the nominative and accusative singular look the same:

• nominative: ткань
• accusative: ткань

This is because ткань is a feminine noun of the third declension.

You can see the case change more clearly in other forms:

• nominative singular: ткань
• genitive singular: ткани
• dative singular: ткани
• instrumental singular: тканью

So the object is accusative here, even though the form does not visibly change.

Because the sentence expresses a general purpose, not one single completed result.

• кроить (imperfective) focuses on the process/activity: to be cutting / to cut as an activity
• A perfective verb would suggest a more specific completed result

So чтобы кроить ткань means for cutting fabric / in order to cut fabric in a general sense.

If you changed it to a perfective verb, the meaning would become more specific, for example:

• чтобы раскроить ткань — in order to cut up / cut out the fabric completely

That is possible in some contexts, but the original sentence is more general and textbook-natural.

Yes. Russian word order is fairly flexible, though the original version is very natural.

Original:

• Выкройка нужна, чтобы кроить ткань.

You could also say:

• Чтобы кроить ткань, нужна выкройка.

This puts more emphasis on the purpose first: To cut fabric, a pattern is needed.

Both are correct. The difference is mostly one of emphasis and style, not basic meaning.

Because Russian has no articles.

So выкройка can mean:

• a pattern
• the pattern

and ткань can mean:

• fabric
• the fabric

The exact meaning depends on context.

In this sentence, English would usually translate it generically:

• A pattern is needed to cut fabric.

Yes, the sentence is general. It does not say who needs the pattern or who is cutting the fabric.

So the meaning is something like:

• A pattern is needed in order to cut fabric
• You need a pattern to cut fabric
• One needs a pattern to cut fabric

Russian often leaves this kind of general subject unstated when it is obvious or unimportant.