Inaccurate Bnd_Box

Hi there!

Even after setting the gap to 0.0, a Bnd_Box does not enclose an added BSpline accurately, but is approximately 0.25 units larger.

Does anybody know a reason for this weird behaviour?

Zoltan Gaal's picture

How do you get the bounding box? If you're using BRepBndLib, it has two function: Add -> slove/accurate and AddClose: fast, but only for polyhedras.

MerryLoggings's picture

I am using BRepBndLib::Add(), not AddClose().

After taking a look at the algorithm's source, I came to the conclusion, that it is not able to produce accurate results for BSplines, due to internal tesselation.

Does anybody know a numerically precise solution of building a bounding box for BSplines? Anything "outside" open CASCADE? Execution time does not matter, but precision.

Stephane Routelous's picture

if you cannot fine a good solution for you, you still have the possibility to triangulate the face/bspline/shape and compute the bounding box of the generated points.

Stephane Routelous's picture

if you cannot find a good solution for you, you still have the possibility to triangulate the face/bspline/shape and compute the bounding box of the generated points.