Questions tagged [nurbs]

Non-uniform rational basis spline (NURBS) is a mathematical model commonly used in computer graphics for generating and representing curves and surfaces which offers great flexibility and precision for handling both analytic and freeform shapes.

Non-Uniform Rational B-Spline (NURBS) is a mathematical model commonly used in computer graphics and computer aided design for representing curves and surfaces which offers great flexibility and precision for handling both analytic and freeform shapes.

NURBS allow representation of geometrical shapes in a compact form. They can be efficiently handled by the computer programs and yet allow for easy human interaction. NURBS surfaces are functions of two parameters mapping to a surface in three-dimensional space. The shape of the surface is determined by control points.

NURBS are commonly used in computer-aided design (CAD), manufacturing (CAM), and engineering (CAE) and are part of numerous industry wide used standards, such as IGES, STEP, ACIS, and PHIGS. NURBS tools are also found in various 3D modeling and animation software packages, such as form•Z, Blender,3ds Max, Maya, Rhino3D, Cinema 4D, Cobalt, Shark FX, and Solid Modeling Solutions. Other than this there are specialized NURBS modeling software packages such as Autodesk Alias Surface, solidThinking and ICEM Surf.

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nurbs straight line between first two control points

I have been working on a piece of code that takes in a curve (cloud of points with x,y coordinates only for now) and parameterises it to approximate the given shape with nurbs. The issue I have is that the resultant parameterised curve is linear(!)…
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cinema4D - Use Boole Object with Extruded Spline

Background I drew a letter (that's about as far as my drawing skills go) by hand using the Freehand Spline tool and extruded it using the Extrude Nurbs. Now as you can see the letter is a P and so I need to subtract the center of it. Therefore I…
LinusGeffarth
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Nurbs trimmed surface

I am reading NURBS surfaces from a STEP file, as well as their boundary curves. Now I want to tessellate those surfaces. Every algorithm I have read talks about boundary curves in parametric space, curve with a parameter t, that maps onto a 2D…
leandro
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Read NURBS control points in Maya from an ASC file

Say I have an ASC file with 100 (x,y,z) coordinates (representing a helix-like world line trajectory). I want to import that file in Maya and create a NURBS with each of the coordinate from my ASC file as a control point. I know how to import asc…
KPJ
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Length of NURBS line

I have a NURBS line which is always composed of 3 points, 3 weights, the knot vector, and is of degree 2. I need to calculate the length of this line, but I can't find any method online to do so. It doesn't have to be 100% accurate, converting into…
djcmm476
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Is it a reasonable to have the following in the BSpline?

I have a closed 3-order(degree 2) BSpline which has the following parameters 9 control points 14 knot points why the relation is 9 + 3 + 2 = 14?
Adam Lee
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Ogre3D - render water with waves by vertex? nurbs?

I have an Ogre3D application and I would like to render a surface that represents the water with waves. I think I am not the only one that has this purpose, so I was looking for an example to follow. I imagine that if I want to create a water…
Simu
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NurbsCurve MatrixMath Maya api Python

I am creating a toolset for creating nurbs curves/surfaces inside maya using python. I have a set of dictionaries that include cvPositions, knots, form etc. each of which describe a preset 3d shape (cube, circle, pyramid etc). I also have a 3d…
Pax
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B-spline Curve ending and starting at origin?

I am generating a B-spline curve of degree 3 with 10 control points. My knot vector has 14 entries ranging from 0 to 1. For some reason my curve always begins and ends at the origin. It also fails to draw a curve if any knot is equal to another…
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QtOpenGL, where is GLUnurbsObj?

In my qt5 code I've included module and I would like to declare a GLUnurbsObj object but my IDE do not recognize it. Is glu.h included in QtOpenGL module?
Colet
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Is there a difference in printing quality between polys vs. NURBS for Maya 3D models?

I've been reading a lot about the many differences, pros and cons between NURBS and polys, but is there a difference when it comes to 3D printing?
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Does increasing the weight of control points have any effect on the continuity of a B-Spline?

I have a basic question relating to NURBs Spline and tension splines like v-splines. Does increasing the weight of a give control point or all control points have any effect on the continuity of the B-Spline ? For example in the case of a C2…
Umang
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Control points in nurbs surfaces

So I've read a lot about nurbs recently and completely understand nurbs curves ( even wrote a small library for it ). But I'm having some problem with surfaces. I can see that I need two sets of control points. My problem is that what the difference…
soroosh.strife
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How to initialize an array of a List

I am learning to build a surface using JMonkey api. The class Surface has a method createNurbsSurface(controlPoints, nurbKnots, uSegments, vSegments, basisUFunctionDegree, basisVFunctionDegree). I am trying to make a simple example to understand…
Esther
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What does RiBasis which is described in RenderMan mean?

I'm working on a plugin of 3ds Max. In this plugin, I export the geometry information into a .rib file which can be rendered by a RenderMan renderer. When I export a nubrs curve's data into .rib file described by RiBasis and RiCurve. I use the…
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