[Bf-docboard-svn] bf-manual: [8557] branches/blender-3.0-release/blender_docs/manual: Geometry Nodes: Update attributes reference page
Hans Goudey
noreply at blender.org
Thu Oct 28 06:29:26 CEST 2021
Revision: 8557
https://developer.blender.org/rBM8557
Author: HooglyBoogly
Date: 2021-10-28 06:29:25 +0200 (Thu, 28 Oct 2021)
Log Message:
-----------
Geometry Nodes: Update attributes reference page
Modified Paths:
--------------
branches/blender-3.0-release/blender_docs/manual/modeling/geometry_nodes/attributes_reference.rst
Added Paths:
-----------
branches/blender-3.0-release/blender_docs/manual/images/modeling_geometry-nodes_attribute-reference_attribute-field.png
Added: branches/blender-3.0-release/blender_docs/manual/images/modeling_geometry-nodes_attribute-reference_attribute-field.png
===================================================================
(Binary files differ)
Index: branches/blender-3.0-release/blender_docs/manual/images/modeling_geometry-nodes_attribute-reference_attribute-field.png
===================================================================
--- branches/blender-3.0-release/blender_docs/manual/images/modeling_geometry-nodes_attribute-reference_attribute-field.png 2021-10-28 03:50:30 UTC (rev 8556)
+++ branches/blender-3.0-release/blender_docs/manual/images/modeling_geometry-nodes_attribute-reference_attribute-field.png 2021-10-28 04:29:25 UTC (rev 8557)
Property changes on: branches/blender-3.0-release/blender_docs/manual/images/modeling_geometry-nodes_attribute-reference_attribute-field.png
___________________________________________________________________
Added: svn:mime-type
## -0,0 +1 ##
+image/png
\ No newline at end of property
Modified: branches/blender-3.0-release/blender_docs/manual/modeling/geometry_nodes/attributes_reference.rst
===================================================================
--- branches/blender-3.0-release/blender_docs/manual/modeling/geometry_nodes/attributes_reference.rst 2021-10-28 03:50:30 UTC (rev 8556)
+++ branches/blender-3.0-release/blender_docs/manual/modeling/geometry_nodes/attributes_reference.rst 2021-10-28 04:29:25 UTC (rev 8557)
@@ -6,20 +6,20 @@
An *attribute* is a generic term to describe data stored per-element in a geometry data-block.
For example, every vertex can have an associated number or vector.
-Attributes can be altered by the nodes in the *Attribute* category, but also some other nodes can
-change the values of specific attributes.
+Attributes can be altered by connecting a value to the *Group Output* node,
+but also many nodes can change the values of specific attributes.
.. note::
- Attribute data types are converted implicitly where possible, just like node sockets.
+ Attribute data types and domains are converted implicitly where possible, just like node sockets.
-Attribute Sockets
-=================
+Named Attributes
+================
-The blue attribute sockets are just string sockets, used to define which attribute in the geometry to use.
-When a node part of the evaluated node tree (connected to the root group input and output),
-the string input allows you to search and choose existing attributes.
+In the modifier, it is possible to access attributes with names, created and used in other areas
+of Blender like shaders, painting, and UV mapping. The attribute can be chosen with a name,
+and the string input allows you to search and choose existing attributes.
.. figure:: /images/modeling_geometry-nodes_attribute-reference_search.png
:align: center
@@ -31,35 +31,60 @@
To the right of the menu, the attribute data type is shown.
+Anonymous Attributes
+====================
+
+.. figure:: /images/modeling_geometry-nodes_attribute-reference_attribute-field.png
+ :align: center
+
+ The *Normal* and *Rotation* ouputs are examples of attribute fields,
+ which refer to an attribute stored on a geometry.
+
+Attributes exposed in Blender's interface all have names. However, for convenience, attributes
+can be passed around with node sockets in geometry nodes groups. In these cases, an *Attribute Field*
+output is created, which can be used by nodes to find attribute data in an input geometry.
+
+
Attribute Domains
=================
-All attributes have a domain and type associated with them. Knowing the domain of an attribute is important
-because it defines which parts of the geometry the attribute can affect.
+All attributes have an associated domain and type. Knowing the domain of an attribute is important
+because it defines how it may be interpolated and used in nodes and shading.
You can use the :doc:`Spreadsheet Editor </editors/spreadsheet>` to determine the domains of attributes.
-- Point domain attributes are associated with the vertices of the mesh or the points in a point cloud.
-- Edge domain attributes are associated with the edges of the mesh.
-- Face domain attributes are associated with the faces of the mesh.
-- Face Corner domain attributes are associated with the corners of the faces of the mesh.
- An example is the ``UVMap`` attribute.
+- **Point** domain attributes are associated with single locations in space with a position.
+ * Vertices of a mesh
+ * Points of a point cloud
+ * Curve control points
+- **Edge** domain attributes are associated with the edges of a mesh.
+- **Face** domain attributes are associated with the faces of a mesh.
+- **Face Corner** domain attributes are associated with the corners of the faces of the mesh.
+ An example is a UV map attribute.
+- **Spline** domain attributes are associated with a group of connected curve control points.
.. note::
For point cloud objects, every attribute has the *point* domain.
-.. tip::
- Use the :doc:`Attribute Convert </modeling/geometry_nodes/attribute/attribute_convert>` node to change
- the domain and type of attributes.
+Attribute Data Types
+====================
+The type of an attribute is the kind of data stored at each element.
+ :Float: Floating-point value
+ :Integer: 32-bit integer
+ :Boolean: True or false value
+ :Vector: 3D vector with floating-point values
+ :Color: RGBA color with floating-point precision
+
.. _geometry-nodes_builtin-attributes:
+
Built-In Attributes
===================
-Built-in attributes always exist, and cannot be removed. Their data type and domain can not be changed.
+Built-in attributes always exist, and cannot be removed. Their data type and domain cannot be changed.
.. list-table::
:widths: 10 10 10 50
@@ -73,18 +98,27 @@
* - ``position``
- *Vector*
- *Point*
- - Built-in attribute describing vertex or point locations, in the modifier
- object's transform space. Any node that changes the location of points will adjust
- this attribute, like the :doc:`Transform </modeling/geometry_nodes/geometry/transform>`
- and :doc:`Point Translate </modeling/geometry_nodes/point/point_translate>` nodes.
+ - Built-in attribute describing vertex or point locations, in a geometry's local space.
+ Any node that changes the location of points will adjust this attribute,
+ like the :doc:`Transform </modeling/geometry_nodes/geometry/transform>`
+ and :doc:`Set Position </modeling/geometry_nodes/geometry/set_position>` nodes.
* - ``radius``
- *Float*
- *Point*
- - A built-in attribute on point cloud data created by
- the :doc:`Point Distribute Node </modeling/geometry_nodes/point/point_distribute>`.
- Used to set the size for the points in the viewport.
+ - A built-in attribute on point clouds used to set the size for the points in the viewport.
+ Also built-in on curves, where it controls the size of each curve control point when
+ converted to a mesh, or for other operations.
+ * - ``id``
+ - *Integer*
+ - *Point*
+ - Created by the :doc:`/modeling/geometry_nodes/point/distribute_points_on_faces` to
+ provide stability when the shape of the input mesh changes, and used on instances to create
+ motion blur. The values expected to be large, with no order. The attribute values are used
+ by nodes that generate randomness, like the :doc:`/modeling/geometry_nodes/utilities/random_value`.
+ Unlike other built-in attributes, this attribute is not required, and can be removed if necessary.
+
* - ``material_index``
- *Integer*
- *Face*
@@ -96,14 +130,6 @@
- Edge attribute used by the Subdivision Surface node and modifier.
The values are limited to a range of 0 and 1.
- * - ``normal``
- - *Vector*
- - *Face*
- - Normal of a face. This is different from the other built-in attributes in that
- it cannot be modified. It is automatically derived from the mesh. If this attribute is
- accessed on non-face domains, it might not be normalized, because it is interpolated
- from normals of neighboring faces.
-
* - ``shade_smooth``
- *Boolean*
- *Face*
@@ -119,18 +145,26 @@
- *Spline*
- Determines whether the spline is cyclic or not.
+ * - ``handle_left``
+ - *Vector*
+ - *Point*
+ - Describes the location of the left handle of a curve control point, on the side
+ of the curve's start. Only exists when the curve contains a Bézier spline.
+ * - ``handle_right``
+ - *Vector*
+ - *Point*
+ - Describes the location of the right handle of a curve control point, on the side
+ of the curve's end. Only exists when the curve contains a Bézier spline.
+
+
Naming Conventions
==================
-These attributes do not exist by default, but are used implicitly by certain nodes. The data type of
-these attributes can be changed, just like any attribute besides the built-in attributes.
+These attributes do not exist by default, but are used implicitly by certain parts of Blender.
+The data type of these attributes can be changed, just like any attribute besides the built-in
+attributes. However, the attributes might be expected by Blender to have a certain type.
-If the attributes don't exist yet, a default value is used, which can depend on the situation.
-For example, in the :doc:`Point Instance Node </modeling/geometry_nodes/point/point_instance>`,
-the default value for ``scale`` is a unit scale of (1, 1, 1), but the default value for new attributes
-in the "attribute" nodes is zero.
-
.. list-table::
:widths: 10 10 50
:header-rows: 1
@@ -139,27 +173,11 @@
- Type
- Notes
- * - ``rotation``
+ * - ``velocity``
- *Vector*
- - Used in the :doc:`Point Instance Node </modeling/geometry_nodes/point/point_instance>` to
- control the rotation of instanced objects or collections. Adjusted by
- the :doc:`Point Rotate Node </modeling/geometry_nodes/point/point_rotate>` and
- the :doc:`Align Rotation to Vector Node </modeling/geometry_nodes/point/align_rotation_to_vector>`.
+ - Used to create motion blur when rendering animations.
- * - ``scale``
- - *Vector*
@@ Diff output truncated at 10240 characters. @@
More information about the Bf-docboard-svn
mailing list