Blocks

Block

Defines a single object that combines one or more objects.

Using blocks lets you:

Create parts libraries.
Update all instances by modifying the block definition.
Keep a smaller model size by using block instances instead of copying identical geometry.
Use the BlockManager
command to view information about the blocks defined in the model.
Use the Insert
command to place block instances into your model, which scales and rotates the instance.

To define a block

Select
the objects.
Pick
a base point for the block.
This is the point around which the instance will be located, scaled, and rotated when it is inserted.
A control point is placed at the base point of the block.
Type a name and description for the block definition properties.
You can also add a URL to the block.
The objects you selected are converted into a block instance.

To redefine a block

Follow the steps for defining a block and re-use the same block name.

Block Instances and Layers

The properties of the geometry (curves, surfaces, etc.) that are contained in the block instance are controlled either by the layer properties or object properties of the geometry itself. Block instances that you insert to the model insert onto the current layer and can be moved to any other layer. There is no relationship between the block instance’s layer and the geometry contained in the block. For example, the block geometry does not change to match the layer color onto which the block instance is inserted.

When the block contains objects on a specific layer, turning that layer off will turn off only the objects on that layer. However, if the layer the block instance is inserted on is turned off, all of the objects will disappear.

Example

Create an object on Layer 01.
Make this object into a block.
Make Layer 02 current.
Insert an instance of the block you just made.
Turn off Layer 02.
The block instance placed on Layer 02 disappears because the (invisible) insertion point of the block instance is on Layer 02, but the original block instance was inserted on Layer 01 when it was created, so it does not turn off.
Turn Layer 02 back on and make it current.
Make some new geometry on Layer 02.
Make this into a block.
Make Layer 01 current and insert an instance of this new block.
Turn off Layer 02.
Because the geometry is on Layer 02, the block instance you inserted onto Layer 01 disappears. The original block instance also disappears because both the geometry and the insertion point are on Layer 02.

Two factors are involved: the layer or layers of the original geometry (there is nothing to stop blocks from containing objects on different layers) and the invisible insertion point of the block instance, which can be on any layer.

Locking Layers

When you lock a layer, only the layer that contains the insertion point of the block instance is locked. If a block has objects that are on the locked layer, but the block instance insertion point is not on that layer, the object itself is not locked because the controlling factor is the layer of the block insertion point.