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USD Curve Export: Pinned CatmullRom Curve #108183

Merged
Michael Kowalski merged 1 commits from SonnyCampbell_Unity/blender:usd-curves-pinned-catmullrom into blender-v3.6-release 2023-05-23 19:18:23 +02:00
Conversation 0 Commits 1 Files Changed 2 +9 -2
2 changed files with 9 additions and 2 deletions
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7
source/blender/io/usd/intern/usd_writer_curves.cc
View File

@ -54,6 +54,13 @@ pxr::UsdGeomCurves USDCurvesWriter::DefineUsdGeomBasisCurves(pxr::VtValue curve_
if (is_cyclic) {
basis_curves.CreateWrapAttr(pxr::VtValue(pxr::UsdGeomTokens->periodic));
}
else if (curve_basis == pxr::VtValue(pxr::UsdGeomTokens->catmullRom)) {
/* In Blender the first and last points are treated as endpoints. The pinned attribute tells
* the client that to evaluate or render the curve, it must effectively add 'phantom
* points' at the beginning and end of every curve in a batch. These phantom points are
* injected to ensure that the interpolated curve begins at P[0] and ends at P[n-1]. */
basis_curves.CreateWrapAttr(pxr::VtValue(pxr::UsdGeomTokens->pinned));
}
else {
basis_curves.CreateWrapAttr(pxr::VtValue(pxr::UsdGeomTokens->nonperiodic));
}

4
source/blender/io/usd/tests/usd_curves_test.cc
View File

@ -192,8 +192,8 @@ static void check_catmullRom_curve(const pxr::UsdPrim prim,
<< "Wrap token should be periodic for periodic curve";
}
else {
EXPECT_EQ(wrap_token, pxr::UsdGeomTokens->nonperiodic)
<< "Wrap token should be nonperiodic for nonperiodic curve";
EXPECT_EQ(wrap_token, pxr::UsdGeomTokens->pinned)
<< "Wrap token should be pinned for nonperiodic catmullRom curve";
}
pxr::UsdAttribute vert_count_attr = curve.GetCurveVertexCountsAttr();