I've never dealt with NURBS in Maya at all, but I know the BS at the end of NURBS stands for B-Spline.
On Monday, 5 March 2018 08:05:54 UTC+11, katisss wrote: > > I want to query a maya nurbs curve for its basis / interpolation style but > nothing in the api looks like it > http://download.autodesk.com/us/may...urbs_curve.html > <http://download.autodesk.com/us/maya/2009help/API/class_m_fn_nurbs_curve.html>I > > seem unable to find anything about it > In the end I need to match it up with the renderman ones: > > A Bezier basis generates a 3D curve that passes through every third > control vertex. The remaining control vertex positions are used to > determine the incoming and outgoing tangent of the curve of the adjacent > vertex that the curve does pass through. When using a Bezier basis with > curves that contain multiple segments (that is, more than 4 control > points), some care should be taken to ensure that incoming and outcoming > tangents line up at vertices that are on the rendered curve, or there > will be a discontinuity in the smoothness of the curve where it suddenly > changes direction. > > B-Spline - While a B-Spline basis function can be somewhat less intuitive > to use in that it generates a curve that typically only > approximately comes close to passing through the given control vertices, > an advantage is that this basis function tends to yield very smooth > curves. Discontinuities in the smoothness of the curve are possible if > multiple control vertices are repeated consecutively. > > Catmull-Rom - This basis function generates a curve that is guaranteed to > pass through every interior, non-endpoint control vertex, > and it tends to generate smooth curves, although there can sometimes be > unexpected "wobbles" in areas of high curvature with this basis function > choice (see images below for an example). Using a B-Spline basis > instead can smooth out the wobbles, although a B-Spline basis typically > produces a curve that does not pass through the control vertices > exactly, unlike the Catmull-Rom basis (for non-endpoint control > vertices). > > Hermite - The Hermite basis function generates a curve that passes through > every other control vertex; the remaining control "vertices" are > actually vectors that determine the tangent of the curve. The length of > the tangent vectors determines the amount of curvature; longer tangent > vectors yield more curvature along the spline than shorter vectors. A > Hermite basis function tends to produce smooth curves, although using a > B-Spline basis can often yield qualitatively a more "natural" or uniform > smoothness along the curve with comparatively less specification > effort. > > Linear - Specifying linear curves yields straight line segments, which can > result in gaps or other geometric artifacts when close to the > camera (this may be acceptable for distant and/or very thin curves). > -- You received this message because you are subscribed to the Google Groups "Python Programming for Autodesk Maya" group. To unsubscribe from this group and stop receiving emails from it, send an email to python_inside_maya+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/python_inside_maya/d42d0657-52f0-48ad-8f74-8b82725d8959%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
