Positions in curves?

[Bixelator Q]

Hi,

I'm trying to use I/OCurve classes for my application, but I'm confused about the positions (m_positions). 

Are they positions of control points (not necessarily on the curve) or curve points (on the curve)?  

Thanks,

Bella.

[Lucas Miller]

I think they are control points based on how they are used in the Maya AbcImport plugin.

Lucas

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[Nicholas Yue]

I believe they are control points base on the following

(1) It's modelled after RenderMan Curves [https://github.com/alembic/alembic/blob/master/lib/Alembic/AbcGeom/OCurves.h#L54]

(2) RenderMan curves are spline based [https://rmanwiki.pixar.com/display/REN25/Curves]

HTH

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Nicholas Yue
https://www.linkedin.com/in/nicholasyue/

[Bixelator Q]

Thank you for your insights! 

Then how about other attributes such as width (m_widths) and uvs (m_uvs)? I would assume they are also per control point. How would I get those values for curve points
if I'm tessellating the curve to line segments?

Bella

[Lucas Miller]

Something to keep in mind about the widths is that it doesn't necessarily have to be per control point, it could be for all curves in that schema or even a single width per curve.

(Sadly I'm unsure about the interpolation math per your original question)

Lucas

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[Bixelator Q]

Thank you for the note! 

I might just try running De Boors on those attributes as well.