3.9. Blocks and Attributes

A block is a named group of entities stored once in the drawing and placed any number of times as a block reference (an INSERT). Moving or editing the definition updates every reference at once, which makes blocks the right tool for repeated symbols — manholes, trees, north arrows, title blocks, standard details.

Blocks live in the drawing they are defined in. They survive a save to .iqz, .dxf and .dwg, and can be imported from another drawing through the Block Manager.

3.9.1. Creating a Block

Draw or select the entities that make up the symbol.
Type BLOCK (alias B) and press Enter to confirm the selection.
Click the base point — the handle the block is inserted by, and the point the reference is rotated and scaled about.
Type a name and press Enter.

The selected entities are copied into the definition (with their coordinates made relative to the base point), removed from model space, and replaced by a single block reference at the base point. Nothing is lost: exploding the reference brings the geometry back.

Note

Block names are unique per drawing and the check is case-insensitive. If the name is already taken, the command reports it and asks again rather than overwriting the existing definition.

3.9.2. Inserting a Block

INSERT <name> (alias INS) starts a rubber-band insert of that block; click to place it.
INSERT with no argument lists the defined blocks and asks for a name.
BLOCKS (alias BL) prints the block table — name and entity count — without inserting anything.
Draw › Block Insert on the menu does the same as INSERT.

A placed reference carries its own scale, rotation and array settings, all editable in the Object Inspector:

Property	Meaning
Block name	The definition this reference points at.
Scale X / Y / Z	Independent axis scales. Negative values mirror the reference.
Rotation	Degrees counter-clockwise about the insertion point.
Columns / Rows	Rectangular array count. A reference with more than one cell is the equivalent of AutoCAD’s `MINSERT`; it draws the whole grid but stays one object.
Column / Row spacing	Centre-to-centre distance between array cells, in drawing units.

3.9.3. Editing a Block Definition

BEDIT <name> (alias BE) opens the block editor: the drawing area switches to the block’s own contents, drawn about its base point at the origin. Draw, modify and erase there exactly as in model space.

BEDIT with no argument prompts for a name; typing ? at that prompt lists every definition with its entity count.

BCLOSE (alias BC) saves the edited definition and returns to the drawing. Every reference to that block redraws with the new contents.

3.9.4. Block Manager

BLOCKMANAGER (alias BM) opens a dialog listing every definition in the drawing as a rendered thumbnail, with the selected block’s details on the right: name, origin (base point), entity count, and the number of references placed.

Button	Action
Insert	Closes the dialog and starts an insert of the selected block.
New	Starts a `BLOCK` definition from the current selection.
Edit	Opens the selected block in the block editor (as `BEDIT`).
Rename	Renames the definition; existing references follow the new name.
Delete	Removes the definition. A block that still has references cannot be deleted — erase or explode them first.
Purge Unused	Deletes every definition with no references left in the drawing. The same clean-up the `PURGE` drawing utility performs.
Import	Reads block definitions out of another `.dxf` or `.iqz` file and adds them to this drawing. This is how a shared symbol library is moved between drawings.

3.9.5. Exploding a Block

EXPLODE replaces a selected block reference with independent copies of the definition’s entities, transformed by the reference’s own scale and rotation. An arrayed reference explodes to every cell. The definition itself is untouched, so other references are unaffected.

3.9.6. Attributes

Attributes are text fields carried by a block reference — a manhole number, a pipe diameter, the fields of a title block — so that two references of the same definition can show different text.

IQcad reads and preserves attributes on import:

An ATTDEF in a block definition (the template that names the field) is staged as text carrying its attribute tag. A tag is a label, not drawable content, so ATTDEFs are not drawn when the block is inserted.
An ATTRIB on a block reference (the filled-in value) is attached to that reference and drawn with it. Attribute values move, rotate and scale with the reference, and are included in its bounding box and in the result of EXPLODE.
Attributes marked invisible are stored but not drawn.

Attribute text round-trips through DXF and DWG in both directions. IQcad has no attribute-definition command of its own: a block with attributes is authored in AutoCAD (or a compatible program) and then used here.

3.9.7. Blocks, Layers and Colours

Entities inside a definition keep the layer, colour and linetype they were drawn with. Entities drawn on layer 0 with colour and linetype set to ByLayer or ByBlock instead inherit from the reference — which is the standard way to build a symbol that takes on the layer it is inserted on. See Layers, Linetypes and Text Styles for the inheritance rules.

3.9.8. Blocks in the File Formats

Format	Behaviour
IQML (`.iqz`)	Definitions and references are written in full, with attributes.
DXF	Written to the `BLOCKS` section as `BLOCK` / `ENDBLK` with `INSERT` references; read back the same way.
DWG	Read and written natively, including `MINSERT` arrays, `ATTRIB` and `ATTDEF`. See DWG Compatibility.
PDF / SVG / image	Flattened to their drawn geometry.

The Drawing Utilities › Purge… command (File › Drawing Utilities) removes unreferenced definitions from the drawing, along with unused layers and styles, before a save.