Because it is a ‘trimmed NURBS surface’,
The underlying shape is provided by the full NURBS surface, in this case a plane defined by a NURBS of degree 1 with only 4 control points
And the ‘valid shape’ is the region inside the trimming curves, that are its boundary lines.
When creating the surface by boundary, it the boundary has ‘4 sides’ (4 strong corners) you can force GiD to create a ‘untrimmed NURBS surface’,
During the surface creation open the contextual menu (click right mouse button) and select ‘No try planar’
and then select the boundary lines to create the surface.
Enrique
De:
gidlist-bounces at listas.cimne.upc.edu [mailto:
gidlist-bounces at listas.cimne.upc.edu] En nombre de Hoang Giang Bui
Enviado el: domingo, 20 de octubre de 2013 2:11
Para:
gidlist at listas.cimne.upc.edu
Asunto: Re: [GiDlist] nurbs data
Thanks. I can use this technique to generate a data file for NURBS. However, I don't understand how GID generate a NURBS surface by tensor product of 2 NURBS curve. I created a NURBS surface on 2D by contour lines but the result is just a rectangle, although the screen showed a seemingly correct surface. May I know why ?
Bui
On Mon, Sep 16, 2013 at 10:47 AM, Enrique Escolano
escolano at cimne.upc.edu wrote:
As Adrià said, you must use Tcl commands to get the NURBS information,
Instead of
GiD_Info list_entities
I recommend you the more specialized GiD-Tcl command GiD_Geometry
e.g.
GiD_Geometry get surface $num
Enrique
De:
gidlist-bounces at listas.cimne.upc.edu [mailto:
gidlist-bounces at listas.cimne.upc.edu] En nombre de Adria Melendo
Enviado el: lunes, 16 de septiembre de 2013 9:26
Para:
gidlist at listas.cimne.upc.edu
Asunto: Re: [GiDlist] nurbs data
Dear Giang Bui,
The only way to access to geometrical data is using a tcl command.
To get information of surfaces you must use:
GiD_Geometry get surface 3
( 3 = num of surface you are interested on )
more info here:
http://www.gidhome.com/component/manual/customizationmanual/tcl_and_tk_extension/special_tcl_commands/geometry
or:
GiD_Info list_entities surfaces 3
( 3 = num of surface you are interested on )
more info here:
http://www.gidhome.com/component/manual/customizationmanual/tcl_and_tk_extension/gid_info_function/list_entities
If you want to do it on a .bas , you must use: *tcl (that is a special command that let you execute any tcl expression)
You can define your own tcl procedures on .tcl file
In the .bas file:
*set var num=3
*tcl(WriteSurfaceInfo *num)
In the .tcl file:
proc WriteSurfaceInfo { num } {
return [GiD_Info list_entities surfaces $num]
}
more info here:
http://www.gidhome.com/component/manual/customizationmanual/template_files/commands_used_in_the_bas_file/specific_commands
Regards,
Adrià
El 15/09/2013 11:04, Hoang Giang Bui escribió:
Dear Gid list,
I'm interested in reading NURBS data in GID problem type. For example to
write custom calculation file using customization command specialized
for .bas file. The problem is that I don't want the mesh from GID, I
want to access raw geometrical data using GID command in .bas file. Does
anyone has any idea on how to achieve this?
BR
Giang Bui
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With Best Regards !
Giang Bui
To learn and to excel
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