What would you do to a Nurbs surface in order to create a curve on that surface?

What would you do to a Nurbs surface in order to create a curve on that surface?

1. Select the surface on which you want to draw a curve-on-surface.
2. In the Status Line, click the “Make the selected object live” icon.
3. Choose Create > CV Curve Tool or Create > EP Curve Tool.
4. Draw a curve on the live surface.
5. When the curve is finished, click the “Make selected object live” icon again.

How do you make a Nurbs surface?

To create a NURBS surface from curves:

1. Draw two or more open NURBS curves to create an enclosed region.
2. Select the NURBS objects being used to create the NURBS surface.
3. Select Model > 3D Power Pack > Create Surface from Curves.

Does AutoCAD use NURBS?

NURBS stands for nonuniform rational B-spline curves. In AutoCAD, you can treat a NURBS surface as a 3D spline with fit points. They also enable better control of the surface; and by using different densities of fit points on AutoCAD 3D surfaces, you can control the degree of precision of the surface.

Is AutoCAD a NURBS?

NURBS stands for nonuniform rational B-spline curves. In AutoCAD, you can treat a NURBS surface as a 3D spline with fit points. … They also enable better control of the surface; and by using different densities of fit points on AutoCAD 3D surfaces, you can control the degree of precision of the surface.

What are the coordinates of the NURBS surface?

Notice the t parameter – it is a coordinate along the curve and has a range of [0, 1]. The NURBS surface have two of those coordinates, by convention called u and v (that’s important for the drawing function). So, the ctrlpoints structure from the code holds all point coordinates.

How is the NURBS curve related to knot vector?

The NURBS curve (Equation 1) with the knot vector (Equation 4) is a Bezier-like curve. It interpolates the endpoints and is tangential at the endpoints to the first and last legs of the control polygon. Most properties nonrational curves apply to NURBS as well. Some details follow later.

How is the NURBS surface drawn in OpenGL?

The NURBS surface is drawn using Evaluator and is defined with the Map function. You’re supposed to define control points in the init (void) function, like so: Good explanation of the function can be found on the MSDN Site for glMap2f.

Are there any drawbacks to using a NURB?

NURBS are genuine generalizations of nonrational B- spline forms as well as rational and nonrational Bezier curves and surfaces. However, NURBS have several drawbacks: Extra storage is needed to define traditional curves and sur- faces.