surface-trim workflow

hi all,
i am still struggling with the basics.
what is the typical workflow to trim a surface with a curve?
to be more precise:
1 planar curve in the xy-plane
2 extrusion surface in z-direction
3 trim curve, planar in yz
now the extrusion surface should be trimmed with the trim curve, projected onto the surface.
also possible: extrude the trim curve, intersect with the extrusion surf, trim
for both workflows, i cant find the appropriate components.
maybe there is a different, more effective workflow...

thanks in advance roberto

Replies to This Discussion

Permalink Reply by David Rutten on May 20, 2009 at 3:27am

Trimming (poly)surfaces with curves is not yet possible, so you'll have to extrude the cutting curve as well, then cap it to make sure it's a closed polysurface (or you could convert the curve into a surface first and then extrude it).

Permalink Reply by roberto gagliano on May 20, 2009 at 3:58am

the trim curve is an open curve and it should stay point-editable.
what is the best workflow to make a closed polysurf from such a curve?
and what would be the final step to trim the extrusion surface with the resulting polysurf? a solid difference?

Permalink Reply by Vicente Soler on May 20, 2009 at 10:15am

There's no trim surface component but it's relatively simple to script a split (if you omit all the error checking). Create the following definition:

In the script component, just paste this line:
a = rhutil.RhinoSplitBrepFace(y, 0, x.ToArray, doc.AbsoluteTolerance)

The script component outputs a split brep, so you need to explode it and extract the surface you want to keep.

Permalink Reply by roberto gagliano on May 20, 2009 at 1:45pm

thanks a lot. i will try to reproduce it....

Permalink Reply by MARIO VERGARA on May 20, 2009 at 3:47pm

hey vicente.
thanks for the script!!!
does ity work with multiple crs and srfs?????
thanks again

Permalink Reply by Vicente Soler on May 20, 2009 at 5:29pm

I forgot to mention that the 'x' input has to be set as 'list'.

Yes, it allow multiple curves and surfaces, but, as it is right now, each surface will be trimmed with all the curves.

If you want each surface to be trimmed with it's corresponding curve of the curve list, disable 'list' in the x input and use this code:

dim crv(0) as oncurve
crv(0) = x
a = rhutil.RhinoSplitBrepFace(y, 0, crv, doc.AbsoluteTolerance)

Permalink Reply by roberto gagliano on May 22, 2009 at 8:17am

hello vicente
i tried to make the trim work, but it does not.
not shure if i really understand, what the different input and output parameters should do, so i post the rhino file and ghx here. could you please check it or post your definition here?
thanks again roberto

Attachments:

trimtst.3dm, 25 KB
trimtst.ghx, 64 KB

Permalink Reply by Vicente Soler on May 22, 2009 at 8:54am

You almost have it. Right click on the 'x' input and set the type hint as 'oncurve'.

Permalink Reply by roberto gagliano on May 23, 2009 at 4:51am

thanks a lot again!

Permalink Reply by Vittorio Menna on July 23, 2009 at 9:58am

hi vicente,
i tried to do that but i m getting a null from the script and this error:

do u know why? thanx

Permalink Reply by Simon Vorhammer on September 24, 2009 at 11:14am

Hi Vicente,
I tried that but it didn´t work out. Could you take a look at my definition and tell me whats wrong with it, please. Thanks very much.

Best, Simon

Attachments:

090924_Circles_on_Srf.ghx, 480 KB
090925_Circles_on_Srf.3dm, 57 KB

Permalink Reply by Nathan Hoofnagle on November 1, 2009 at 8:46pm

HI vincente

Is it possible that you could upload your actual ghx file so we could all disect ourselves and save you the trouble of the mass reply? I have tried to replicate this function and only get a 'null' value to return. I am new to scripting and the component so I could be missing something. x is set to 'list'. What do you mean by (if you omit all the error checking). Any ideas?