Instances(インスタンス)

3種類のインスタンス。

In addition to storing real data like a mesh or a curve, objects can store instances, which themselves can reference more geometry, an object, or a collection. The purpose of instancing is to allow duplicating geometry and storing it in an object, without duplicating the actual data. This optimization allows render engines like Cycles to handle the same geometry data in many different locations better than when the data is duplicated.

Each instance keeps track of which geometry it corresponds to and how the instanced is transformed compared to it's source geometry. Instances can also store the id attribute, which is used to correct motion blur when instances move in an animation.

Instances can be created with geometry nodes using the Instance on Points(ポイントにインスタンス作成)ノード.

警告

現在、ジオメトリノードからのインスタンス化は 、プロパティエディタの Instancing(インスタンス化) パネルからのインスタンス化と混在させることはできません。

ネストしたインスタンス化

Since instances can store a geometry, and a geometry can contain instances, nested instancing is possible. In other words, it is possible to instance an instance, or even a collection of instances. For example, by default, the Instance on Points(ポイントにインスタンス作成)ノード will create nested instances by instancing instances on the points of real geometry.

A node group that creates nested instancing by chaining Instance on Points nodes.

Here, nested instancing is used to distribute geometry that contains both a mesh and instances. The output geometry contains a "real" mesh and a group of instances. Each instance contains a sphere mesh and many instances of a cone geometry.

上記の例のインスタンス化されたジオメトリのツリー。

What makes this method helpful is the output geometry only contains three unique meshes: the plane, the sphere, and the cone. This would make the performance much better if the meshes were more complicated.

警告

Only eight levels of nested instancing are supported for rendering and viewing in the viewport. Though deeper trees of instances can be made inside geometry nodes, they must be realized at the end of the node tree.

Realizing Instances

The term "realizing" instances referes to converting the instances into unique geometry. When instances are realized they will take up more memory and manipulation to geometry will have to be processed individually rather the once per instancing geometry.

To realize instance use the Realize Instances(インスタンス実体化)ノード.

インスタンス処理

Almost all nodes that process geometry do so by processing each unique geometry separately rather than realized geometry. For example, if a Subdivision Surface Node was placed at the end of the example above, it would only have to subdivide three meshes, rather than each instance of a mesh. Another important example is processing with the output of the String to Curves Node, where each unique character only has to be processed once.

この方法はパフォーマンスを大幅に向上させることができますが、操作の結果は特定のジオメトリのすべてのインスタンスで同じになることを意味します。インスタンスごとに一意の結果を得るには、 Realize Instances(インスタンス実体化)ノード を使用できます。