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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Is there any difference between closed and open NURBS on control and knots?

I am wondering if there is any difference between closed and open nurbs on control and knots. I checked many documents, but cannot find the exact answer, so asked here.
Adam Lee
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Finding the bounding box (axially aligned) of a parametric range of a 3D NURBS surface

I'll apologize in advance in case this is obvious; I've been unable to find the right terms to put into Google. What I want to do is to find a bounding volume (AABB is good enough) for an arbitrary parametric range over a trimmed NURBS surface. For…
spurserh
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How is one NURBS surface rendered?

I know that GPU is efficient for rendering triangles. GPU can't render NURBS surface directly. From the link NURBS in the OpenGL Graphics Pipeline, we know that. To render NURBS, triangulation is required. I don't know where triangulation…
Jogging Song
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longest and shortest curves selected

I'm trying to create a script that will select a bunch of Nurbs curves, and measure the length of those curves. So ideally I could select the shortest curve leaving longer curves unselected (or the opposite). So far i have this: import maya import…
pj1138
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how to process sweeping surface whose section curve is a polygon?

I've got stumped by a question,recently.Now, I have a polygon and a NURBS Curve,then I want to make a sweeping surface that the NURBS Curve as a trojectory curve and the polygon as a section curve. Problem is the polygon can be triangle or…
mhsj
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NURBS surface - Finding points equally spaced

I have a NURBS surface of degree p,q, with the control points and the knot vectors U and V. I need to retrieve points on the surface that are distanced by xStep millimeters in the u direction and xStepV millimeters in the v direction. I searched…
Toyo
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How can I sectionwise scale a nurb surface

I'm trying to find a way to interpolate between sections of a wing.I have n aerofoil sections with n installation angles. However I have some more code which gives m scale fators for the wing geometry, where m>n. I've constrcted a surface nurb with…
wookie1
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Determing intersecting quads?

Is there a possibility to detect whether an object intersects another object in Opengl ? For example: I have 2 quads(later nurbs),I am moving these quads so that at some point they intersect. Now I would like to cut out those parts which are lying…
buddy
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texture does not map the whole nurbs surface

glGenTextures(1, &texName[0]); glBindTexture(GL_TEXTURE_2D, texName[0]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,…
Sean
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how to obtain 3d vertice of a NURBS surface with OpenGL

the function glEvalCoord2f() takes two coordinates as arguments and gives back a point in 3d space,I want to get the point with 3d coordinate,how to do it ?here is my code: #include #include #include #include…
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What is the best way to export a Blender Nurbs object to Rhino or Solidworks for mold production?

My question would be to model in blender and send the object to rhino or solidworks, for mold production. Would this be possible in nurbs? thank you for any help, thanks Edward When I export from Blender (.obj) to Rhino and export in (.xt) to…
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Creating Nurbs Curve from points in Maya

I'm trying to create a function that takes a list of xyz points and creates a nurbs curve in Autodesk Maya, using python. To generate the points, I've been grabbing the points from an existing curve that was made manually, using this: import…
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relocation R_X86_64_32S

Good day, friends! I have a problem with the NURBS library in the QT framework. I am doing a project on QT using the NURBS library. And it was after I added just one command to the code that is directly related to the NURBS library and compiled my…
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PCL Bspline fitting

I am currently trying to create a bspline surface from a pointcloud with 100,000 plus points. I cant seem to find a way to get the bspline definition. I dont have a way to access the knot vector or the control points. I see a nurb surface is created…
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Curve fitting with both interpolation and approximation

I need to fit a globally smooth cubic b-spline to interpolate through some points, while approximating others (i.e., 3rd case): As I understand it, given the above example, approximation would involve something like this: Input: Set of data points…
Matt-Heun Hong
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