# Tag Info

Accepted

### How to raytrace Bezier surfaces?

First off, here's the Kajiya method I think you're thinking of: Kajiya, Ray Tracing Parametric Patches, SIGGRAPH 82. The tech report version might be more informative. What I hope you get from that ...
• 751

### Algorithm to find the center of a Bezier curve

Bézier curves are mathematical entities and have no clearly defined center. One can in fact define many different things as the center of the Bézier curve. I have tried to depict some of the possible ...
• 8,159

### How to raytrace Bezier surfaces?

is it a total pipe dream to hope to solve the Ray/Bezier-surface intersection algebraically Yes, it's a pipe dream. A bicubic Bezier patch is an algebraic surface of degree 18. To intersect a ray ...
• 330
Accepted

### How to calculate matching roundness of two offset rectangles?

What you (probably) want to achieve is something like this: When having a closer look at one of the corners and add a few lines, we see this: The black lines indicate that the center points of the ...
• 1,200
Accepted

### Determining Rational Quadratic Bezier Curve Weights for Circle

Check out the section on Circular Arcs and Circles, from Ching-Kuang Shene's excellent computational geometry course notes: [G]iven three control points P0, P1 and P2 such that P0P1 = P1P2 holds, if ...
• 811

### Reliable test for intersection of two Bezier curves

An alternative way to formulate the problem is to define a function that gives the distance between points on the two curves, as a function of the curves' parameters. Then attempt to find the global ...
• 23.7k

### Reliable test for intersection of two Bezier curves

[Disclaimer: I think the following should work but have not actually coded it myself] I couldn't think of a "trivial" method of producing a yes/no answer but the following would be a reasonable ...
• 3,941
Accepted

### Apply distortion to Bézier surface

Edit: changed the answer according to new images and clarification. for every control point p(k, n) p'(k, n) = ( p(k, n) - p(k) ) * d * l(k) + p(k, n) where <...
• 166

### How to raytrace Bezier surfaces?

Another option, which I used a couple of decades ago (yikes!), is to use Toth's scheme from 1985 that employed interval arithmetic to narrow down the search space. IIRC, eventually it will resort to ...
• 3,941
Accepted

### Bezier Curve Tool Controlled by Mouse

Instead of using cubic Bezier spline, you should use cubic Hermite spline. For cubic Hermite curve you specify the segment end points and tangents, which is what you then control in the tool. Hermite ...
• 3,541

### Does this 3D rendering method exist? How is it called? Is there any C++ algorithm for it?

Yes, such rendering exists. It is called a parametric surface and there are several methods you can render such entities. In this case you are talking of bezier patches. Turn the object into enough ...
• 8,159

### Does this 3D rendering method exist? How is it called? Is there any C++ algorithm for it?

The 1994 game Ecstatica and its 1997 sequel rendered ellipsoid segments instead of triangles, but I don't think anyone else has ever used this exact technique. Direct raytracing of Bézier patches was ...
• 6,440

### Join two bezier curves so that the result is two-times continuously differentiable

For 2 bezier curves to connect and be continuous at all, the last control point of the first curve (C in your case) must be the same as the first control point of the next curve (D). So c3 has to ...
• 3,321

### Bicubic bezier surface from 4 bezier curves

Yes, its pretty standard stuff. Most 3D applications our there can do this. Since the nomenclature of 3d applications is not standardized, the tool has different names in different applications: Loft (...
• 8,159