Toolbar Menu Shortcut



Blocks >

Create Block Definition

Ctrl (CMD) + B

The Block command defines a block object from the selected objects and replaces the selected objects with an instance of the block.

Using blocks lets you

Define a block in a model

  1. Select the objects.

  2. 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 block control point is placed at the base point of the block.

  3. Type a name for the block definition.

    The block definition is created with the active unit system (model/layout).

Block Definition Properties


The name of the block definition.

See: Naming conventions in Rhino


Optional descriptive information.


Adds hyperlink information to a block definition. This information can be retrieved with the Hyperlink command.


A description of the URL.


A web address. Click the address to open the page in the default browser.

Define a block by inserting another file into a model

Define a block by dragging another file onto a model

  1. Drag and drop a supported file from Windows Explorer onto the model.
  2. Specify the Insert file option.
    A block definition will be added to the model.

To redefine a block


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.

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.


Grouped objects will not maintain their grouped status inside a block.

Properties by parent

This option is only useful for objects in blocks. Think of a block instance as a container that contains objects (block members). A block instance is the parent of its block members. A block instance has its own properties. If By Parent is selected in the properties of a block member, the properties will be controlled by the block instance.

Simple block example:
Nested block example:

By Parent can be selected for Display Color, Linetype, Print Color and Print Width in object properties. For the Render material, select Use Object Parent. Render materials are only visible in Rendered and Raytraced display modes by default.


Toolbar Menu



Blocks > Block Definitions


Panels > Block Definitions

The BlockManager command opens the Block Definitions panel for managing the block definitions in the model.

Block Definitions panel

Create a new block definition

Creates a new block definition from objects in the model as what the Block command does.


Show <n> hidden block definitions

Lists hidden block definitions.

Hidden block definitions have names beginning with * (asterisk character), such as *Chair.

Show reference block definitions

Lists the blocks in linked block definitions as separate top level items.

Show unused block definitions

Lists the block definitions that do not have instances in the model.

Show all objects in block definitions

Lists objects in block definitions. Otherwise, only lists top level block definitions.

Show children of nested blocks

Lists the block definitions nested in other ones.

Group similar block instances

Duplicate nested blocks in the same block definition will be listed only once.

Show embedded block definitions

Lists the block definitions saved in the model.

Show embedded and linked block definitions

Lists the block definitions saved in the model also referencing external files.

Show linked block definitions

Lists the block definitions referencing external files.

Search box

Enter a text string to filter items in the list.

Options menu

Collapse All

Collapses the list to only show items of the top level.

Expand All

Expands the list to show items of all levels.

Get selection from viewport

Selects the block definitions referenced by the selected block instances in the viewport.

Purge unused block definitions

Deletes the block definitions that do not have any instances inserted to the model or layout spaces.

Use the Purge command to delete more types of unused data.

Embedded and linked block should

These options decide how "embedded and linked" block definitions will update each time a model is opened.

Always update

Update without any prompt.

Prompt when update required

The Block Definitions to Update dialog box appears for actions.

Never update

Never update and prompt.

List structure


The block definition name.

Top Level

The instance number of the block definition.


The instance number of the block definition nested in other block instances.


The instance number of the block definition regardless of Top Level and Nested.

Object Count

The total number of objects and direct nested blocks in the block definition.

Block definition

Block A, B, C, and D are block definitions.

The icons indicate the definition types:

Embedded and linked

Block definition context menu

Select Instances

Selects instances of the selected block definition in viewports.


Inserts the block definition to viewports as block instances.

Or, you can drag and drop a block definition into a viewport.


Edits the block definition name.


Deletes the selected block definition and all of its instances in the model.

Block definitions nested in another block definition cannot be deleted.


Makes a new copy of the selected block definitions.


Reloads the external file to see the latest changes.

The icon appears behind the block definition name when the linked block is out of date.


Lists the details of the selected block definition in the Block Instance Info dialog box.


Saves the block definition's component objects to one of the file formats supported by Rhino.

Instance/Nested instance numbers

Block A has 5 top-level instances and 2 nested instances in the model.

Objects in block definition

Block A contains a curve (a1) and a surface (a2).

The icons indicate the object types.

Block object context menu


Selects the object in viewports.


Edits the name of the block object.


Deletes the block object from the block definition.

Block definition with nested blocks

Block A and B are nested in Block D.

The icon indicates they are nested blocks.



The name of the block definition.

Pop out

Brings up a larger and resizable Block Definition Properties window.


Displays the text information of the block definition.


The preview image of the block definition.


(Embedded block definitions only)

Block units

The units of the block definition.

If you change the Block units, you will be prompted if you want to scale the block definition.

Definition Type


Saves geometry in the model. The block definitions will not update when the external file changes.

Embedded and Linked

Saves geometry in the model and maintains a link to the external file. Linked geometry will update when the external file changes. If the external file cannot be located, the geometry saved in the model is still available.


Only maintains a link to the external file. Linked geometry will update when the external file changes. If the external file cannot be located, the geometry will be missing in the model.

Linked block definitions use both absolute and relative paths.

When the external file of a linked block is not found

The missing block location is marked with a text dot object listing the missing block name.

For a description of the process Rhino uses to locate files used by worksessions and linked instance definitions, see Rhino Wiki: File finding.

To resolve the issue

  • Click the Browse button to locate the missing block file.
    Or, right-click on the block name and select Delete from the right-click context menu to remove the link.

Options for "Embedded and linked" and "linked"


The path and name to the external file.


Change the path of the external file.

Found at:

The path of the external file.


Edit the external file with the associated application.

Read linked blocks from external file

Linked blocks in the file being inserted are also inserted.

Layer Style

Defines how layer names are organized


Merges layers with the same names.


Creates a parent layer using the name of the linked file. Layers in the linked file appear as sub-layers under the parent layer.


Adds hyperlink information to a block definition. This information can be retrieved with the Hyperlink command.


A description of the URL.


A web address. Click the address to open the page in the default browser.


Opens the URL in the default web browser.

Related commands




New in V8



Blocks > Add Objects to Block

The AddObjectsToBlock command adds objects to an existing embedded block definition.


  1. Select an instance of an embedded block definition.

  2. Select the objects to add to the block definition

To remove objects from a block definition, use the BlockEdit command.


Toolbar Menu



Blocks >

Edit Block in Place

The BlockEdit command allows selecting a block instance to change the block geometry and update the block definition.


  1. Select a block instance to edit.
    Double-click a block instance.
    The block geometry opens in the Rhino window. All other objects are locked.
    You can now edit the geometry in the block using any editing techniques.
  2. Click OK to accept the editing.
    To cancel, click the [X] button at the upper-right corner.
Command-line options


Linked blocks are not stored in the Rhino file, but are a connection to an external model. To edit linked blocks, Rhino opens the external model in a separate instance of Rhino. The current editing session is paused until the external file is locked.


Prompts to open a linked block.


Opens the linked block without prompting.

In the Edit Linked Block dialog box, checking the Don't ask this question again... box automatically sets the PromptToEditLinkedBlocks to No.

Block Edit options

The Block Edit dialog box displays the block name and a list of any blocks nested in it.

Add Object

Adds selected objects to the block definition. If the selected object is a block, this becomes a nested block and will display in the tree the next time the BlockEdit command is run.

The object added is copied to the block definition and the original object remains in the model.

Remove Object

Removes selected objects from the block definition.

When the block is updated, the removed objects are added to the model as separate individual objects.

Set Base Point

Repositions the block insertion point.

When the block is updated, the block instance will shift so the new insertion point is placed at the block insertion location.



Toolbar Menu



Blocks > Reset Block Scale

The BlockResetScale command resets the x, y, and z scales of a block instance to 1, or applies the best-fit scale to all axes.

A non-uniform scaled block instance is reset to the original scale.

Command-line options


Resets the x, y, and z scales of a block instance to 1.


If any two axes have the same scale, applies the scale to the third axis.

If all three axes have different scales, applies the average scale to all axes.

See Also

Edit a block

Manage blocks


Toolbar Menu

Not on toolbars.

Not on menus.

The CopyLinkedBlockDefinition copies a linked block with Reference style layers.

To create your own example:

  1. Create a simple file called BlockDef.3dm that will be used as a block definition.
  2. Start a new model called "FancyModel.3dm".
  3. Use the Insert command to create a linked block definition with "reference style" layers.
  4. Name this block "A".
  5. Run the CopyLinkedBlockDefinition command and copy "A" to new block named "B".
  6. Run the CopyLinkedBlockDefinition command and copy "A" to new block named "C".
  7. Adjust the layer settings for the three blocks.
  8. Run BlockManager and see that you have three linked blocks that reference the same "BlockDef.3dm".




New in V8


The CreateUniqueBlock command duplicates the block definition of a block instance and changes the block instance to reference the new block definition.



Toolbar Menu


Not on menus.

The ReplaceBlock command redefines selected block instances with a different block definition.


  1. Select block instances to change in the viewports.
    If you select one of several instances in the model, a command-line message displays the number of additional instances in the model.
  2. Select a block instance that uses the desired block definition.

Command-line options


Displays a list of block definitions in the model to select from.


Selects all instances of the current block definition including unselected, hidden, and locked instances.


Selects no additional instances. Only the selected instances will be changed.


Selects the replacement block definition by entering its name.

See also

Work with blocks, groups, and worksessions

McNeel Wiki: Using blocks




Rhinoceros 8 © 2010-2024 Robert McNeel & Associates. 28-Feb-2024