Hello, I am trying to understand why the following doesnt work :
I have a simple structure like this :
root.usda → Two prims each referencing a different asset, asset_1, and asset_2. Both are flagged instanceable.
asset_1.usda → a cube, with a material assigned. The material is brought in by a reference, which is flagged instanceable.
asset_2.usda → a cube, with a material assigned. The material is brought in by a reference, which is flagged instanceable. The material layer referenced here is the same as in asset_1.
Now - I would have expected the material to end up instanced / reused, even if the assets are different.
However, instead, I end up with two prototypes for the material…each instanced once…?
Is “nested” material instancing like so no expected to work? Am I missing something?
At a high level, i want to reference in different assets, which themselves reference the same material - and I want that material to be instanced in the composed scene.
Here are the layers :
root.usda
#usda 1.0
(
defaultPrim = "root"
metersPerUnit = 0.0254
upAxis = "Z"
)
def Xform "root"
{
def Xform "box" (
instanceable = true
prepend references = @./Asset_1.usda@
)
{
matrix4d xformOp:transform = ( (1, 0, 0, 0), (0, 1, 0, 0), (0, 0, 1, 0), (0, 0, 0, 1) )
uniform token[] xformOpOrder = ["xformOp:transform"]
}
def Xform "box2" (
instanceable = true
prepend references = @./Asset_2.usda@
)
{
matrix4d xformOp:transform = ( (1, 0, 0, 0), (0, 1, 0, 0), (0, 0, 1, 0), (10, 0, 0, 1) )
uniform token[] xformOpOrder = ["xformOp:transform"]
}
}
Asset_1.usda :
#usda 1.0
(
defaultPrim = "root"
metersPerUnit = 0.0254
upAxis = "Z"
)
def Xform "root"
{
def Cube "Asset_1" (
prepend apiSchemas = ["MaterialBindingAPI"]
)
{
rel material:binding = </root/mtl/mysharedmaterial>
}
def Scope "mtl"
{
def Material "mysharedmaterial"
(
prepend references = @./mysharedmaterial.usda@</mysharedmaterial>
instanceable = true
)
{
}
}
}
asset_2.usda :
#usda 1.0
(
defaultPrim = "root"
)
def Xform "root"
{
def Cube "Asset_2" (
prepend apiSchemas = ["MaterialBindingAPI"]
)
{
rel material:binding = </root/mtl/mysharedmaterial>
}
def Scope "mtl"
{
def Material "mysharedmaterial"
(
prepend references = @./mysharedmaterial.usda@</mysharedmaterial>
instanceable = true
)
{
}
}
}
mysharedmaterial.usda :
#usda 1.0
(
)
def Material "mysharedmaterial"
{
token outputs:surface.connect = </mysharedmaterial/mysharedmaterial.outputs:surface>
def Shader "mysharedmaterial"
{
uniform token info:id = "UsdPreviewSurface"
float inputs:clearcoat = 0
float inputs:clearcoatRoughness = 0.01
color3f inputs:diffuseColor = (1.0, 0.0, 0.0)
float inputs:displacement = 0
color3f inputs:emissiveColor = (0, 0, 0)
float inputs:ior = 1.5
float inputs:metallic = 0
normal3f inputs:normal = (0.047379453, 0.013452399, 0.86981463)
float inputs:occlusion = 1
float inputs:opacity = 1
float inputs:opacityThreshold = 0
float inputs:roughness = 0.5
color3f inputs:specularColor = (0, 0, 0)
int inputs:useSpecularWorkflow = 0
token outputs:surface
}
}
