add support for scene

requirements.txt

@@ -1 +1,2 @@
-usd-core
+usd-core
+compas >= 2.0

scripts/scene.py

@@ -0,0 +1,22 @@
+import compas
+from compas.scene import Scene
+from compas.geometry import Box, Sphere, Translation
+from compas.datastructures import Mesh
+from compas_usd.conversions import stage_from_scene
+
+scene = Scene()
+group1 = scene.add_group(name="Boxes")
+group2 = scene.add_group(name="Spheres", transformation=Translation.from_vector([0, 5, 0]))
+
+mesh = Mesh.from_obj(compas.get("tubemesh.obj"))
+mesh.flip_cycles()
+scene.add(mesh, name="MeshObj", transformation=Translation.from_vector([-5, 0, 0]))
+
+for i in range(5):
+    group1.add(Box(0.5), name=f"Box{i}", transformation=Translation.from_vector([i, 0, 0]))
+    group2.add(Sphere(0.5), name=f"Sphere{i}", transformation=Translation.from_vector([i, 0, 0]))
+
+print(scene)
+
+stage = stage_from_scene(scene, "temp/scene.usda")
+print(stage)

src/compas_usd/conversions/__init__.py

@@ -20,6 +20,7 @@
     apply_rotate_and_translate_on_prim,
     frame_and_scale_from_prim,
 )
+from .scene import stage_from_scene
 
 __all__ = [
     "prim_from_box",
@@ -36,4 +37,5 @@
     "apply_transformation_on_prim",
     "apply_rotate_and_translate_on_prim",
     "frame_and_scale_from_prim",
+    "stage_from_scene",
 ]

src/compas_usd/conversions/geometry.py

@@ -1,7 +1,7 @@
 from pxr import UsdGeom
 from compas.geometry import Frame
 from compas.geometry import Box
-from compas.utilities import flatten
+from compas.itertools import flatten
 from compas.geometry import transpose_matrix
 
 from .transformations import apply_rotate_and_translate_on_prim
@@ -76,7 +76,7 @@ def prim_from_sphere(stage, path, sphere):
     """
     prim = UsdGeom.Sphere.Define(stage, path)
     prim.GetPrim().GetAttribute("radius").Set(sphere.radius)
-    UsdGeom.XformCommonAPI(prim).SetTranslate(tuple(sphere.point))
+    UsdGeom.XformCommonAPI(prim).SetTranslate(tuple(sphere.frame.point))
     return prim
 
 

src/compas_usd/conversions/scene.py

@@ -0,0 +1,102 @@
+from compas.scene import Scene
+from compas.scene import SceneObject
+from compas.data import Data
+from compas.geometry import Box
+from compas.geometry import Sphere
+from compas.geometry import Transformation
+from compas.datastructures import Mesh
+from compas_usd.conversions import prim_from_transformation
+from compas_usd.conversions import prim_from_box
+from compas_usd.conversions import prim_from_sphere
+from compas_usd.conversions import prim_from_mesh
+
+from pxr import Usd, UsdGeom
+
+
+def stage_from_scene(scene: Scene, file_path: str) -> Usd.Stage:
+    """
+    Converts a :class:`compas.scene.Scene` to a USD stage.
+
+    Parameters
+    ----------
+    scene : :class:`compas.scene.Scene`
+        The scene to convert.
+    file_path : str
+        The file path to the USD stage.
+
+    Returns
+    -------
+    :class:`pxr.Usd.Stage`
+        The USD stage.
+    """
+    stage = Usd.Stage.CreateNew(file_path)
+    UsdGeom.SetStageUpAxis(stage, UsdGeom.Tokens.z)
+    for obj in scene.root.children:
+        prim_from_sceneobject(stage, obj, parent_path=[scene.name])
+
+    stage.Save()
+    return stage
+
+
+def prim_from_sceneobject(stage: Usd.Stage, sceneobject: SceneObject, parent_path=[]) -> Usd.Prim:
+    """
+    Converts a :class:`compas.scene.SceneObject` to a USD prim.
+
+    Parameters
+    ----------
+    stage : :class:`pxr.Usd.Stage`
+        The USD stage.
+    sceneobject : :class:`compas.scene.SceneObject`
+        The scene object to convert.
+    parent_path : list[str], optional
+        The path to the parent prim.
+
+    Returns
+    -------
+    :class:`pxr.Usd.Prim`
+        The USD prim.
+    """
+    path = parent_path + [f"{sceneobject.name}"]
+
+    transformation = (
+        sceneobject.transformation
+        if sceneobject.transformation is not None
+        else Transformation()
+    )
+
+    prim = prim_from_transformation(stage, "/" + "/".join(path), transformation)
+    if sceneobject.item is not None:
+        prim_from_item(stage, sceneobject.item, parent_path=path)
+
+    for child in sceneobject.children:
+        prim_from_sceneobject(stage, child, parent_path=path)
+
+    return prim
+
+
+def prim_from_item(stage: Usd.Stage, item: Data, parent_path=[]) -> Usd.Prim:
+    """
+    Converts a :class:`compas.scene.SceneObject` to a USD prim.
+
+    Parameters
+    ----------
+    stage : :class:`pxr.Usd.Stage`
+        The USD stage.
+    item : :class:`compas.scene.SceneObject`
+        The item to convert.
+    parent_path : list[str], optional
+        The path to the parent prim.
+
+    Returns
+    -------
+    :class:`pxr.Usd.Prim`
+        The USD prim.
+    """
+    path = parent_path + [f"{item.name}"]
+    if isinstance(item, Box):
+        prim = prim_from_box(stage, "/" + "/".join(path), item)
+    elif isinstance(item, Sphere):
+        prim = prim_from_sphere(stage, "/" + "/".join(path), item)
+    elif isinstance(item, Mesh):
+        prim = prim_from_mesh(stage, "/" + "/".join(path), item)
+    return prim