reading trimmed surface by parasolid kernel

Hi,

There are couple occasions when using Parasolid kernel to read trimmed
surface of from a prt/step/sldprt file, I found that there are some
differences in topology for the boundary representation.

Say I have a rectangle model with circular hole of 4mm diameter. The
hole is actually fill by a 4mm diamater cylinder.

Consider the circular hole(CH) represented by 2 curves : curve A-B and
curve B-A whereas
the end part of the cylinder(CY) is represented by 2
curves too: curve C-D and curve D-C.

Most of the times, curve A-B does not match curve C-D and
curve B-A does not match curve D-C.

As a result, I ended up having a mesh mismatched at those region.

I wonder in what way I could fix the problem like after getting the
trimmed surface from the kernel, I could do addition step that able to
identify that CY and CH share common boundary and ensuring both curves
having the same end nodes?

Or is there any better solution to this?

Is this very common in prt/sldprt that they are not as strict as IGES
topologically?

Please correct me if I am wrong.

Thank you.

jeff

 

Say I have a rectangle model with circular hole of 4mm diameter. The

Was there an actual boolean union of the two bodies?

What program are you talking about and how do they not match? Going back to
your rectangular model - if there was an actual merging of planar surfaces then
the curves should be irrelevant as all you've done is deleted the cylindrical
thru bore surfaces and the circular trim boundaries in the planar surfaces. If
the curves are not coincident, except for end vertices, they were incorrectly
defined. There is not a CAD system in common use today that will have trouble
with accuracy on planar analytic curves.

Still sounds like incorrect definition or the surfaces have not been merged if
we're still working with the block. If the surfaces are more complex then there
is a problem with edge coincidence or continuity.

There is no such thing as IGES topology. IGES is a translation medium used to
translate various topology representations.

Maybe you should start over and describe in detail what you are doing with what
program and the results you are observing. There is a real good chance the
problem is the mouse pilot.

 

Jeff,

First of all,,, what are you trying to do ?????

Are you importing data into Solidworks ?????

Are you trying to write your own Parasolid based application ???

Your post is very fuzzy.

Mark