SrfSeam misbehaviour/bug


#1

This one really caused me to scratch my head (and throw about 9 hours of production patterning away).

To replicate:

Draw a sphere.
Increase the isocurve display density to 9. This is fine and on a symmetrical object like a sphere it creates evenly spaced isocurves as you would expect.
Now move the surface seam to a new spot.

The surface isocurves are now randomly spaced. And of course the randomness is just a little too subtle to be seen by eye, so silly old me assumed everything was still evenly spaced.

See attached.


#2

Looks like it’s related to the “special case degree 2” of spheres.
Rebuilding to a high enough degree to keep the deviation to a minimum seems to shut the problem up.
It’d be nice if this could be fixed though (if mathematically possible) because it sure as hell caused me a bunch of grief.


(Pascal Golay) #3

On a sphere, is there any reason not to just rotate the the whole sphere? You can see the point arrangement may change pretty dramatically as well with SrfSeam, I don’t know that this is a bug exactly, it is how the command works, it has to add knots and spans to the surface.

-Pascal


#4

Hi Pascal,

No problem to rotate the whole sphere IF I know that’s what I need to do at the beginning of the design process.
It was just such a nasty and unexpected surprise to have that happen, that I thought I’d mention it in case someone else gets trapped by it. I’m certainly not likely to make that mistake again :wink:

Cheers, Steve