Instances are created with an "index" parameter used for persistence over
time through animation. Currently the geometry nodes instancer passes
the index in the array for this value, but the arrays created by the
"Point Distribution" node aren't necessarily stable in this way when
the input mesh is deformed. In D9832 we already mostly solved this
problem with an `id` attribute. The solution here is to create instances
with this attribute as well.
It's important to note that deforming the instanced points *after*
distribution will usually be a better solution for this problem. This
solution is likely still important though.
Differential Revision: https://developer.blender.org/D10024
In the report, the geometry is copied because it has two users and the
final join node needs to write to it. The join node also happens to
remove attributes apparently, because it exposed a mistake in the "copy"
method of the `MeshComponent` class. The copy is supposed to be
a deep copy, but the vertex group name map was not duplicated.
Differential Revision: https://developer.blender.org/D9991
The Point Instance node can instance entire collections now.
Before, only individual collections were supported.
Randomly selecting objects from the collection on a per point basis
is not support, yet.
Last part of D9739.
Ref T82372.
This is the initial merge from the geometry-nodes branch.
Nodes:
* Attribute Math
* Boolean
* Edge Split
* Float Compare
* Object Info
* Point Distribute
* Point Instance
* Random Attribute
* Random Float
* Subdivision Surface
* Transform
* Triangulate
It includes the initial evaluation of geometry node groups in the Geometry Nodes modifier.
Notes on the Generic attribute access API
The API adds an indirection for attribute access. That has the following benefits:
* Most code does not have to care about how an attribute is stored internally.
This is mainly necessary, because we have to deal with "legacy" attributes
such as vertex weights and attributes that are embedded into other structs
such as vertex positions.
* When reading from an attribute, we generally don't care what domain the
attribute is stored on. So we want to abstract away the interpolation that
that adapts attributes from one domain to another domain (this is not
actually implemented yet).
Other possible improvements for later iterations include:
* Actually implement interpolation between domains.
* Don't use inheritance for the different attribute types. A single class for read
access and one for write access might be enough, because we know all the ways
in which attributes are stored internally. We don't want more different internal
structures in the future. On the contrary, ideally we can consolidate the different
storage formats in the future to reduce the need for this indirection.
* Remove the need for heap allocations when creating attribute accessors.
It includes commits from:
* Dalai Felinto
* Hans Goudey
* Jacques Lucke
* Léo Depoix
