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.

125 questions
0
votes
0 answers

How to merge two 2D Splines on orthogonal planes into one 3D Spline in python

I need to create a 3D Spline (or NURBS, both would be possible as I can convert these internally) based on two 2D Splines (or NURBS). The two base Splines are on orthogonal planes in a 3D space. Let's say, for simplicity, spline A is on the…
0xhexdec
  • 17
  • 6
0
votes
1 answer

How to select only Nurbs curves in scene with Python in Maya (without objects in hierarchy)

Suggest please a method to select all Nurbs curves in the Maya scene using Python. But I must select only curves without any other objects in the hierarchy before or after. For example, I have a hierarchy like…
Ihor Hurin
  • 17
  • 7
0
votes
0 answers

Does nurbs-python geomdl feature similar functionality as R mba package

I have R code that uses the multilevel B-spline approximation as implemented in the mba R package for two tasks. Interpolate a surface defined by around 1000 (x, y) coordinates and scalar values to a new coordinates. Use the mba to create a…
FordPrefect
  • 320
  • 2
  • 11
0
votes
0 answers

What is the validation and verification of NURBS?

I have point clouds on the object. If I want to model the object by using NURBS, How can I understand NURBS modeling is appropriate for this data? In the other words What is the validation and verification of NURBS?
Atiyeh
  • 1
  • 1
0
votes
1 answer

Nurbs curve parameters in Maya?

I get a Maya .ma file, I want to understand the parameters for nurbsCurve, the file has contents like this: createNode nurbsCurve; # create a nurbsCurve setAttr -k off ".v"; # set attribute about knots? setAttr ".cc" -type "nurbsCurve" #…
XueYu
  • 2,355
  • 29
  • 33
0
votes
1 answer

How to add a geomdl NURBS curve to an existing axis?

I'm trying to work with NURBS using geomdl. I already have an matplotib axis, where several elements are plotted using: plot() scatter() imshow() (for Background image) add_patch The result looks like this:…
0
votes
1 answer

How I can parse nurbs surface from dxf file? Or do you know library(for js, if exists or any other language) for parsing it?

I am trying to parse autocad nurbs surface and draw with triangulation using webGL in javascript. I already looked for dxf parser by bjnortier. It supports majority entities like line,arc,3Dface, polyline, lwpolyline, etc., but doesn't support…
Toni
  • 3
  • 3
0
votes
1 answer

Using Nurbs Surface (Verb) in webGL, indices are always wrong unless I use corners instead of controlPoints

I am trying to make Verb's Nurbs Surface to work with vanilla webGL (cheating a bit with webgl-utils though). PIXI.js also yields the same results, corners work, but not the control points. I could do it using corners…
Hooman Askari
  • 1,486
  • 16
  • 30
0
votes
0 answers

What is a non rational function and how to choose its degree?

I am trying to approximate a surface from a set of given points in 3D space in sets like [[X1,Y1,Z1],[X2,Y2,Z2],.....] and I found this very nice library called geomdl this approximates the surface quite well. but I am not able to understand its…
0
votes
1 answer

How to combine Rational B-spline Surfaces?

How to combine Rational B-spline Surfaces into one or fewer? How do metrics such as tolerance, u/v degree, u/v span influence the final result, if any?
June Wang
  • 499
  • 2
  • 6
  • 20
0
votes
2 answers

How to move the scaled point and keep the shape of the curve?

For a curve, I wanna move the start and end point to new position, and then how to keep the shape of the curve ? From the points which circulated on the yellow curve, move them to red curve position which circulated on the red curve, how to keep…
Jim Green
  • 1,088
  • 3
  • 15
  • 40
0
votes
0 answers

How to find a point on a b-spline that is on the normal plane of a point on another b-spline using goemdl / nurbs

So the first problem will be explaining what I am after clearly. I have two non-rational 3D b-splines. The first b-spline it the guiding spline. The second b-spline is a reference and it is essentially 'inside' of the first spline. ( the splines…
Burtski
  • 451
  • 5
  • 19
0
votes
0 answers

How to grade the NURBS curve with the grading point when use CAD?

When we parse DXF file which related to CAD, we can see the grade rule table file and the base size DXF file which export dxf using Gerber model . The base size DXF provides some knot points which on the NURBS curve , how to grade the NURBS curve…
Jim Green
  • 1,088
  • 3
  • 15
  • 40
0
votes
1 answer

Find the radius ( or curvature ) at a point on a bspline using geomdl / nurbs

I would like to find the curvature at a given point on a 3D b-spline. I believe that I want to use the derivatives of the spline at that point to calculate the curvature at that point but I do not understand how. I have defined a 3D bspline (taken…
Burtski
  • 451
  • 5
  • 19
0
votes
1 answer

Is this a bug in NURBS-python when updating the control points?

I used NURBS-python and found an interesting problem, and not sure this is done like this intentionally or it is simply a bug. I would like to introduce this with 2 codes. The first one should output the same as the second one, while it is not. The…
Westack
  • 105
  • 5
1 2 3
8 9