Working with Blocks

Bolt heads, valve symbols, a title logo — drawings repeat things. A block lets you draw something once, give it a name, and place it wherever it's needed. Every placement draws from the same definition, so changing the block changes all of them.

---

Prerequisites

Before you begin, ensure that:

• You have some geometry drawn that you want to reuse, and can select it with the Select tool.

---

Blocks and Placements

Two words are worth keeping apart:

• A block (its definition) is the named, stored drawing: the geometry, its base point, and its name. It isn't drawn anywhere by itself.
• A placement is one use of a block in the drawing, with its own position, scale and rotation. A block can have any number of placements, or none.

A placement behaves as one object: click any part of it and the whole placement is selected, and it moves, rotates, scales and deletes as a unit.

---

Making a Block

Make Block is on the Draw partition of the command bar, and in the Draw menu.

1. Select the geometry the block is made of. It can include lines and curves, text notes, hatches, and placements of other blocks.
2. Start Make Block. The prompt reads "Click the point the block is placed by".
3. Click the base point — the point every future placement is positioned and rotated by. A corner, a centre or an insertion point is usually right; use object snaps to hit it exactly.
4. Type a Block name in the dialog and click OK.

The selected geometry becomes the block, and it's replaced in the drawing by a single placement of that block, in exactly the same spot — so nothing appears to move, but it now selects as one object. The status bar confirms: "Made the block Bolt."

If you start Make Block with nothing selected, it says "Select the geometry the block is made of first."

Tip: choose the base point deliberately

The base point is where the block is held when you place it. For a symbol that sits on a line, pick the point that should touch the line; for a part, pick a datum you'll snap to. It's much easier to choose well now than to work around later.

---

Placing a Block

Insert Block is on the Draw partition, next to Make Block.

1. Start Insert Block. The prompt reads "Click where the block goes", and a preview of the block follows the cursor.
2. Set the options on the Tool Options row if you need to (below).
3. Click where the block's base point should go.

The block is placed — "Placed Bolt." — and the tool stays active, so each further click places another. Press Escape when you're done.

Scale and angle are remembered for the next time you place a block.

Note: scaling differently across and up

A placement scaled differently in X and Y draws its circles as polylines and its text stretched, and the status bar warns you when you place one. Such a placement also can't be exploded (below). Keep Lock X/Y on unless you really need it off.

If the drawing has no blocks yet, the prompt reads "This drawing has no blocks yet — make one first".

---

The Blocks Tab

The side panel's third tab — View → Properties and Layers (Ctrl+1), then Blocks — lists every block in the drawing:

• Each row shows a picture of the block, its name, and how many times it's placed — or not placed. A block with placements scaled differently across and up says so.
• Find a block filters the list by name.
• Double-click a block to place it at the drawing's origin, selected, ready to move where you want it.
• Selecting a row makes it the block Insert Block places next.

Right-click a block for:

A block that's defined but not placed stays in the list — useful for a library of symbols you've imported but not used yet.

---

Changing a Block: Redefine

Redefining replaces what a block contains, and every placement updates to match.

1. Draw or select the geometry that should become the block's new contents.
2. Either:
   • start Make Block, click a base point, and give the existing name — Pingendum asks "Bolt is already a block in this drawing, placed 4 times. Replace what it contains? Every placement will change." — and click Yes; or
   • run Redefine block from command search (Ctrl+Shift+P), then pick the block from the list — "Replace the contents of:".
3. The selection becomes the block's contents, and every placement redraws: "Redefined Bolt, and its 4 placements followed."

A block can't be made to contain itself, directly or through another block — Pingendum refuses with "That would put the block inside itself."

---

Exploding a Placement

To turn a placement back into ordinary, independent geometry, select it and choose Explode — on the right-click menu, or Modify → Explode. The status bar confirms: "The block is now plain geometry."

• The result is independent: editing it doesn't affect the block or any other placement, and the block itself stays in the drawing.
• Any relations inside the block aren't carried over — exploded geometry is unrelated.
• A placement scaled differently across and up can't be exploded, because its circles would no longer be circles.

The same Explode command also splits a multi-line text note into single-line notes — see Working with Text.

---

Blocks and Layers

A placement goes on the layer that's current when you place it, like anything else you draw.

What's inside the block follows one simple rule:

• Geometry in the block that has no layer of its own takes the placement's layer, colour and style. Hide or freeze the placement's layer and the whole block disappears, rather than leaving its contents behind.
• Geometry in the block that was on a named layer keeps that layer wherever the block is placed.

This is why CAD users draw block contents on layer 0: a block made that way takes on whatever layer you place it on.

---

Attributes

Some blocks carry attributes — named text values such as a part number or a tag, which can differ from one placement to the next. In this release, attributes come with blocks imported from DXF or DWG files; you can't add new attribute definitions to a block yourself.

To see or change the values, right-click the block on the Blocks tab and choose Attributes…. The dialog lists every placement of the block, one row each, with a column per attribute. Edit any cell and click OK — all the changes are one undo step. Attributes that are the same on every placement are shown once above the table, and can't be edited there.

---

Moving, Copying and Transforming Placements

• Move, Rotate and Scale move, turn and resize placements with the rest of the selection. Symmetry reflects them. Mirror skips them — see Transforming and Duplicating Sketch Geometry.
• Delete removes a placement; the block stays in the Blocks tab.
• To stop clicks and selection boxes picking placements, turn off Edit → Selection filter → Pick blocks.

Note: a placement's own settings

In this release the Properties panel doesn't list block placements, so a placement's scale, angle and layer can't be changed there after it's placed. Use Rotate and Scale on it, or delete it and place it again with the right options on the right layer.

---

Blocks in DXF and DWG

Blocks travel both ways:

• Export as AutoCAD 2000 DXF (or DWG) writes each block as a real BLOCK and each placement as an INSERT, so the receiving CAD system gets blocks, not loose lines. Use AutoCAD 2000 rather than R12 for a drawing with blocks.
• Import brings a file's blocks in as blocks, nested ones included, with their attributes — see Exchanging Drawings as DXF.

---

Next Steps

You now know how to:

• Make a block from a selection, choosing its base point and name
• Place a block with Insert Block or from the Blocks tab, at any scale and angle
• Redefine a block so every placement updates, and explode a placement back into geometry
• Predict which layer a block's contents draw on
• Read and edit attribute values on imported blocks

Next: Dimensioning a Drawing