2.2Blocks: create, insert, redefine & block library
A block is a group of objects combined into a single reusable element: a door, a window, an electrical symbol, a piece of furniture, a screw… Instead of redrawing the same component a hundred times, you create a block once and insert it as many times as needed. It is a pillar of productivity and consistency in AutoCAD.
The great power of blocks: redefinition. Modify a block's definition, and all its insertions update automatically — a colossal time-saver. This is how you build libraries of reusable components (often through tool palettes or DesignCenter). Blocks also pave the way for the advanced features: attributes (data), dynamic blocks (parametric) and schedules, covered at level 3.
Section vocabulary
- Block
- Set of objects combined into a single named, reusable element (door, symbol, furniture…).
- Create a block (BLOCK / B)
- Define a block from objects, with a name and an insertion point (base point).
- Insert (INSERT / I)
- Place an occurrence of an existing block in the drawing, with scale and rotation.
- Redefinition
- Modify a block's definition: all its insertions update automatically.
- Block library
- Collection of reusable blocks, accessible through tool palettes or DesignCenter.
What is the great advantage of a block?
In practice — Creating and reusing blocks
- Draw a component (a door, a symbol) and turn it into a block (B): give it a name and a relevant insertion point.
- Insert this block (I) several times, with different scales and rotations.
- Redefine the block (modify its definition) and watch all the insertions update at once.
- Store your blocks in a tool palette to build your reusable library.
Key points to remember
- A block combines objects into a reusable element (drawn once, inserted everywhere).
- Redefining a block updates ALL its insertions automatically.
- You build libraries (tool palettes, DesignCenter).
- Blocks pave the way for attributes, dynamic blocks and schedules (level 3).
Frequently asked questions
What is the difference between a block and a group?
A group simply associates objects to handle them together, but each group remains independent. A block is a single definition from which occurrences are placed: modifying the definition updates all the insertions, and the block can carry attributes, be dynamic, be counted in a schedule. For any reusable, standardized component, the block is vastly superior to the group.
A « normal » block or one with an insertion point: what's the difference?
The insertion point (base point) is crucial: it is how the block « attaches » when inserted. Choosing it well (a corner, a center, a logical snap point) makes insertion precise and fast. A poorly placed base point forces you to reposition the block at every insertion. Always take the time to define a relevant base point when creating the block.