Using blocks allows you to group together entities which belong to a single feature in a drawing. Once grouped in a block, the entities can be more easily manipulated together.
The use of blocks means that a design feature (a collection of entities) can be:
- given a meaningful name
- added very quickly to another part of the drawing
- removed quickly
- modified once and the modifications propagated automatically throughout the drawing
- copied easily into other drawings
Blocks may be nested to any level. That is, any block may itself contain blocks (often referred to as its sub-blocks).
Use Block - New to create a block from selected entities. Use Block - Insert Block to create a new block insertion from an existing block. If you want to modify entities within a block, you need to move into the block first - use Block - Change Current or Block - Quick Change to change your current block (see below). When you have made the changes, use Block - Save Current to save them. See Block Tools for further information.
The organisation of the layers and blocks in the current drawing is shown on the Drawings Hierarchy page of the Impact Explorer. You can right-click in the Block Inspector area to display a context menu showing many of the block tools.
Every block insertion has a parent block - this is the block (or layer) in which the block was inserted. (If you move from a block to its parent, and then to the parent’s parent, and so on, you will eventually reach the drawing layer.)
Many tools, notably the Diemaking tools, have options to create blocks containing any new geometry. This is normally configured in the Master Tool Settings.
A similar concept of Groups is also available, which offers a simplified solution for grouping entities together.
Block Insertions
It is important to distinguish between a block and a block insertion. A block is a group of entities but it is not itself an entity. A block insertion is an entity which references a block. A block insertion also contains information about its position and size. A block can be inserted into a drawing several times - so several block insertions will refer back to a single block. A block can exist even if there are no longer any block insertions which refer to it. Block insertions may be manipulated - selected, moved, deleted - in the same way as other entities. Blocks can only be deleted by purging them.
The Current Block
Impact uses the concept of the current block. If you want to modify the entities within a block (or add more or delete some), you must first make the block your current block. Otherwise you will not be able to select individual entities, only the entire block insertion entity.
When you first create a drawing, there are usually no blocks. Your current block is the layer itself. When you create entities, including block insertions, they are added to the current layer.
The name of the current block (or the current layer) is optionally shown on the status bar, to remind you whether you are within a block.
As you change your current block, the extents indicator, if displayed, changes to reflect the extents of the chosen block insertion. Additionally the entities which are not in this block may be greyed out. The options may be set from the Visibility form.
While you are within a block, you can also change the position of the origin. Simply use Block - Move Block Origin to pick a new origin point. This point becomes the new origin for the block coordinate system. It also becomes the point by which new insertions of the block are positioned.