Solidworks Nurbs Editor

Hello all,

I have written a small program that allows you to directly edit the
nurbs control points of virtually any face. It is seamlessly integrated
with the solidworks GUI. If you would like a copy of this free
software, simply email me at:



and I will send you the zipped program.

I really would like to get some feedback on this, as it is something
that i always wished was in SW (so I wrote it myself) and I would like
to see how many other users are interested.

Thanks!

_andrew_

 

My email is:

swnurbs _AT_ plasmadevelopment.com

Sorry about that

 

Pretty cool. And it is just a macro.

I tried it in 2004 and it seemed to work fine.

It is similar to some other SW functions in that you first have to
create the surface and then you can play with it.

I don't know if it make sense, but it would be nice to be able to set
tangency on the edges.

 

Hey Andrew,

Does it work on all versions of SW? 2003-2005?
Send it anyway. Leave out the obvous part in my mail.

Andy

 

ok well initial impression seems good but

1) crashed SW shortly after I picked a cylindrical face and had a warning
message about not being a...sorry didn't catch it...was trying multi body at
the time
2) I think it needs 5 nurbs in either direction to be more useful for
symmetrical changes.
3) I had to pull quite a long way out on the points ...didn't seem to made a
lot of difference to the actual shape...needs some sort of scale factor?

will look some more...
cheers
neil

 

I think he mentioned that in the README file under periodic surfaces.

Well, yes, it would be nice to have the ability to have more or fewer
control points

and

to be able to group them and move them together

but

it is pretty cool just the way it is.

I noticed the same thing, but that is kind of the way it is with NURBS.
This way it is not overly sensitive.

 

Andrew,

Looks like you're out of the guitar case business? You might remember
me from a past life.

Anyway, Your macro works nicely. To quickly give some shape to a face,
it's a nice tool, and at this point, the price is right.

This actually works a lot like a product called Shape Works by a company
called BarenBoym (www.baren-boym.com). Their version costs money, and
it has some handy directional drag handles at each control point, plus,
you can change the number of control points on the fly.

Also, take a look at a newish SolidWorks product called Cosmic Blobs.

It might be cool if yours did a "replace face" function automatically so
it felt more like you were working directly on the solid.

It would also be very cool if it could span multiple faces.

As always, some sort of curvature / tangency control at the edges would
be nice

It's interesting that it won't work on cylindrical (periodic) faces as
someone else pointed out, but it will work on spline based non-
analytical surfaces.

Something I've been hoping for with tools like this is some sort of a
"push" tool, like a thermoforming tool. Kind of like the "Indent"
function in SW05. I know there's the Deform / Surface Push, but that
isn't controllable, and it doesn't seem like it's possible to do
anything which you could call "intentional".

Anyway, it's cool stuff, thanks for sharing it with us!

Matt Lombard

 

Assume that your NURBS are *at least* cubic.
Leave the outer 3 sets of points alone. Then C2 will
remain (if it existed in the first place).
IF all you want is simple tangency, leave the outer 2
sets of points alone (assuming you had tangency to
begin with).

(Outer N points is defined as counting inwards from any edge,
starting with the point on the edge.)

Beyond that, I think that it gets complicated <G>.

 

Ummmm ..... knot points on the surface or hull vertex points?

 

P.
1) it wasn't mentioned in the readme in my email....but even so I would like
just the warning and not the crash which came immediately afterward.
2) specifically I was wishing for an odd number of points so that one fell
on the mid point of a surface.
3) it is good but it would be even cooler if some small changes were made
e.g.
it wasn't an issue of being overly sensitive it was about the movement being
more reflective of the actual result.

I hope Andrew appreciates that we really like what he has done and we are
offering suggestions for its improvement.

cheers
neil

 

Thanks everyone for the interest and kind words. This macro is still a
baby, so i will try to include the wish list in the next release. If I
compile it, then i will probably implement some openGL to run the
points instead of the windows GDI. The point distance issue is just a
fact of life when it comes to b-spline surfaces, however, I will look
into weighting the points to have more or less of an effect on the
shape. Also, im looking at creating a "preview surface" so you can see
what the surface will look like without commiting changes. Keep it up!
_andrew_

 

It might be handy to be able to generate more points on the surface
and use those instead of the original control points at times.
Where they are located could be sort of a variable .... as could
their density, local & otherwise.
Don't know if that's been considered. Neither should be hard to do.
but does allow the advanced user of such tings far wider control.
It also incerases either the degree of the surface or the number
of patches in it. Both can be options I suppose.

 

One thing about NURBS is that the control points are not usually on the
surface or anywhere near it. There are ways to generate control points
from information on where the surface is or should be, but that takes
more programming.

For this kind of application I use Rhino as the benchmark for the user
interface since I know a little Rhino and a lot of other people are
familiar with it, i.e., the learning curve will be shorter.

In production we have to be careful of the fact that the surfaces will
not regenerate if they are opened on a seat of SW that does not have
this macro installed. I would assume that this is not true if the model
is exported to a dumb geometry format like parasolid.

 

Still waiting for my copy.

"Preview surface" is likely within the ability of SW API. Look up
"temporary bodies" in the SW API help.

If you would like a hand turning this into an addin, drop me a line at
rol[3+1}_AT_LiquidSchwarz.com (do the math & remove the brackets)
I can also be contacet via <http://www.EsoxRepublic.com>.

 

Hmmmm, I wonder if SW corp could have been any less descriptive when it
came to periodic nurbs in the API... The macro now supports periodic
surfaces in any and all directions (you can now edit doughnuts!!) I
also fixed that variable edge problem emailed to me by Paul. To those
still waiting to get your copy, I apologize for the delay, I will be
posting it on my website so you may download it soon.
Thanks guys!

_andrew_

 

There are two "types", sort of.
The points on the surface (or near it of a tolerance
& weighting is allowed) and hull vertex points, whch
are handy displays to show curvature related things
and to modify when such is allowed.
If you look at an IGES file, as an example, it will
show the points on the surface which define the
surface.

Sounds like you are thinking of the hull vertex
points only. Are they the ones that define the surface
in SW?

 

Mostly its a matter of terminology.

In UniGraphics, and in geometry texts I have read, B-splines are
defined by poles, which are as you described. The poles "attract" the
spline by a factor varying from t=0 to t=1 along the length of a spline
patch, with "t" varying along the length of the spline patch.

Spline defining points are derived from the poles (closest point on
spline to pole, I believe). It is possible to manipulate a surface by
either splines or poles. Poles generally provide better curvature
control, while points provide better positional control. UniGraphics
has this ability. It would be nice to see it in SW.