NurbsCurves support in UsdView

[Quaxo (Anton Khelou)]

I’ve been working with UsdGeomNurbsCurves lately and testing out the some of the test files in the Git repo with USDView. 2 questions came up:

• Are the order/knots Attributes supported in UsdView. I am trying to change the value and see how it affects the curve, but I do not see any changes. Is this normal – all I see is the lattice of the curve? Is there some sort of option that I need to turn on to see the interpolation?
• In the following test file section OpenUSD/pxr/usdImaging/usdImagingGL/testenv/testUsdImagingGLNurbsCurves/testCurves.usda at release · PixarAnimationStudios/OpenUSD · GitHub, I noticed that there are 3 elements in the order attribute but there is only 1 element in the curveVertexCounts attribute – what does it mean to have 3 orders for 1 curve? (presumably there should be 1 order per curve?)

[spiff (F Sebastian Grassia)]

I am not a curves expert, and can only answer the first question, which is that your experience is as expected: none of our renderers (nor Hydra core) currently provides tessellation support for NurbsCurves. That said, to see (in Storm) tessellation of even BasisCurves, yo uneed to bump up usdview’s “Complexity” to something other than the default, lowest level.