add group

[Licini]

Adding a Group object to Scene, which is a custom SceneObject. The usages are similar to Three.js:

from compas.scene import Group
from compas.scene import Scene
from compas.geometry import Point

scene = Scene()

group = Group(name="My Group")
scene.add(group)

point = Point(0, 0, 0)
group.add(point)

print(scene)

<Tree with 3 nodes>
└── <TreeNode: ROOT>
    └── <Group: My Group>
        └── <GeometryObject: Point>

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 61.85%. Comparing base (333d0a8) to head (fc52d3d).
Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1444      +/-   ##
==========================================
+ Coverage   61.83%   61.85%   +0.01%     
==========================================
  Files         207      208       +1     
  Lines       22321    22333      +12     
==========================================
+ Hits        13803    13814      +11     
- Misses       8518     8519       +1     

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[gonzalocasas]

I think this looks good, it's surprising that such a small change creates this feature, I guess this is just giving it a cleaner name to abusing empty SceneObjects

[Licini]

I think this looks good, it's surprising that such a small change creates this feature, I guess this is just giving it a cleaner name to abusing empty SceneObjects

@gonzalocasas I realized an issue when I'm adding group to the serialization test, where Data can not be serialized without __ data __ implemented, which means we still have to extend Data even it is not really doing much here..., in this case allowing SceneObject to take None item is perhaps a better route. It can also reduce footprint of serialized Scene especially when we have a lot of groups. Could you take a look again let me know what you think?

[tomvanmele]

LGTM just a minor remark

[tomvanmele]

should this not be: if item and not isinstance(item, Data)?

[Licini]

Indeed, looks more elegant, updated!

[tomvanmele]

Also, i was wondering if it would be cleaner to use a factory classmethod on SceneObject, instead of overwriting __new__

[Licini]

Also, i was wondering if it would be cleaner to use a factory classmethod on SceneObject, instead of overwriting __new__

Sure, Factory pattern could be more readable than __ new __, I can experiment the idea a bit in another PR