Two families of cubic Hermite curves forming a parametric net are the basis of the bicubic Hermite surface. Learn more about Chapter 7: Bicubic Hermite. Parametric Bicubic Surfaces. ▫ The goal is to go from curves in space to curved surfaces in space. ▫ To do this, we will parameterize a surface. bicubic surfaces. We want to define We want to define smooth surfaces too. Parametric but also have the nice Hermite property of continuous tangent vector.
|Published (Last):||12 May 2012|
|PDF File Size:||2.39 Mb|
|ePub File Size:||18.2 Mb|
|Price:||Free* [*Free Regsitration Required]|
This is the course material for? Bilinear Surface A bilinear surface is derived by interpolating four data surfacw, using linear equations in the parameters u and v so that the resulting surface has the four points at its corners, denoted P 00P 10P 01and P 11as shown in Figure 1. For a 2-D parametric curve represented in terms of its arc length s. Do the results surfsce sense to you?
Equation 11 can be further expressed as. Use proper mesh and views to display the surface. They are the bicuvic corner data points, the 8 tangent vectors at the corner points two at each point in the u and v directionsand the 4 twist vectors at the corner points. Use proper mesh and view to display the surface. Hermite Bicubic Surface Because the blending functions are linear, the bilinear surface tends to be flat.
Because the blending functions are linear, the bilinear surface tends to be flat. Principle Curvature The principle curvatures are the roots of the following equation: Thus, the boundary matrix for the F-surface patch becomes Figure 3.
For a 2-D parametric curvenote thatandEquation 21 can be transformed into. And the unit normal vector is given by.
L11 Hermite Bicubic Surface Patch
This special surface is useful in design and machining applications. Describe how you can determine the shortest distance between, say, San Francisco and Taipei. A bilinear surface is derived by interpolating four data points, using linear equations in the parameters u and v so that the resulting surface has the four points at its corners, denoted P 00P 10P 01and P 11as shown in Figure 1.
The Hermite bicubic surface can be written in terms of the 16 input vectors: Construct a sphere to represent the earth. We assume that this point is obtained by dividing surfface line segment between P 0 v and P 1 v in the ratio u: EFand G are the first fundamental, or metric, coefficients of the surface.
The Gaussian curvature at a point on the surface is defined as. A parametric surface patch with its boundary conditions The twist vector at a point hermiye a surface measures the twist in the surface at the point.
L11 Hermite Bicubic Surface Patch – Free Download PDF
Finally, write down the surface equations of your F-surface patch and write a simple Matlab program to draw the F-surface. The mean curvature is defined as. Surface geodesics can, for example, provide optimized motion planning across a curved surface for numerical control machining, robot programming, and winding of coils around a rotor.
Write down eurface bilinear surface equation using Equation 4.
Substituting Equation 1 and 2 into Equation 3 gives the following equation of a bilinear surface: The attributes to be stored would be only four corner points because the surface represented by Equation bicugic can be reconstructed from these four corner points.
The normal to a surface is another important analytical property.
Write a simple Matlab program to draw the surface. We call the extreme values the?
Similarly, P uv is obtained from P 0 v and P 1 v as. Define 4 corner points in 3D space. The paths that have minimum lengths are analogous to a straight line connecting two points in euclidean space and are known as geodesics. Construct the boundary condition matrix [B] in Equation The twist vector at a point on a surface measures the twist in the surface at the point.
Referring to Figure 5, when we rotate the plane around the normal, the curvature varies and has a maximum and minimum value in two perpendicular directions.