[GiDlist] displaying quadratic elements

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Mark Smith

[GiDlist] displaying quadratic elements

Post by Mark Smith »

Enrique,
Thanks very much, I ended up doing something very similar myself, I took it
a bit further thought for quadratic surface elements. I wrote out the mesh
using files import/export write mesh then applied an external routine to
produce a batch file which connected each 3 point edge as an arc. The
resulting geometry just then needed to have the midside nodes deleted from
the arc and the result looks very good.
See attached images of an unstructured meshed spherical surface.
Should I get enough requests for the code I'll spend the time and post it
here.

Regards
Mark.

P.S. I think it would be useful if there was a down load area on gidlist
where users could place their routines which they want to share like you
find on Yahoo groups this would have the added benefit of reducing
attachments on the emails. Just a thought







-----Original Message-----
From: Enrique Escolano [mailto:escolano at cimne.upc.es]
Sent: 09 August 2002 16:55
To: gidlist at gatxan.cimne.upc.es
Subject: Re: [GiDlist] displaying quadratic elements


1- It is easy create a small template .bas to convert the surface mesh to
wireframe mesh.:
Example (for quatratic triangles and repeating shared edges)

Wireframe.bas

MESH dimension 3 ElemType Linear Nnode 2
Coordinates
*loop nodes
*nodesnum *nodescoord
*end nodes
end coordinates

Elements
*set var cont=0
*loop elems
*set var cont=operation(cont+1)
*cont *elemsconec(1) *elemsconec(4)
*set var cont=operation(cont+1)
*cont *elemsconec(4) *elemsconec(2)
*set var cont=operation(cont+1)
*cont *elemsconec(2) *elemsconec(5)
*set var cont=operation(cont+1)
*cont *elemsconec(5) *elemsconec(3)
*set var cont=operation(cont+1)
*cont *elemsconec(3) *elemsconec(6)
*set var cont=operation(cont+1)
*cont *elemsconec(6) *elemsconec(1)
*end elems
end elements

A quadratic triangle can be written also as four linear triangles.

Copy this file Wireframe.bas inside the directory /templates, and use it
with
Files-Export-Using Template bas (only mesh)-Wireframe

After , read the ouput file with Files-Import-GiD mesh


2- You can convert the surface mesh to geometry (DXF format) using the
template DXF.bas
Files-Export-Using Template bas (only mesh)-DXF
Note: this template write quadratic elements as linear, but it can be
modified.

3- If you have interest to read/write directly the GiD .geo format, I'
attach a beta documentation of this format
(this document is spanish language and word format)

Regards

Enrique Escolano

----- Original Message -----
From: "Mark Smith" mailto:mark.smith at linx.co.uk mark.smith at linx.co.uk
To: mailto:gidlist at gatxan.cimne.upc.es gidlist at gatxan.cimne.upc.es
Sent: Thursday, August 01, 2002 4:33 PM
Subject: RE: [GiDlist] displaying quadratic elements


Miguel
I can convert a mesh into a wireframe mesh of lines which I can then
import
into GiD to see all the mid-side nodes (via a .bas file and a little mesh
cleanup routine) but it occurred to me that I could convert it into
surface
geometry file (and then able to see a non faceted mesh) if only I knew
what
GiD's .geo file format was, would you be prepared to put this information
into the public domain?
Or is there an alternative method of saving a mesh as geometry?

Best regards
Mark

-----Original Message-----
From: Miguel A. de Riera Pasenau [mailto:miguel at cimne.upc.es]
Sent: 01 August 2002 13:22
To: mailto:gidlist at gatxan.cimne.upc.es gidlist at gatxan.cimne.upc.es
Subject: Re: [GiDlist] displaying quadratic elements


Hi,

now th only way to show the position of the middle nodes is
to draw the labels of these nodes. the middle nodes are not
drawn due to performance questions. we are planning to add
an option to drawn those middle nodes just with interconected lines
( not curves).


miguel

Mark Smith wrote:

Win98 GiD 6.3.0b

Dear GiD team
When I label the nodes of a quadratic element mesh I can see the
mid-side
node numbers but the mesh shown is the simple linear one. Is there any
way
of showing the quadratic mesh or are there any plans to do so?
Like wise, the rendered surface of a quadratic mesh appears far more
faceted
than is the case, which make it difficult to judge how well the surface
mesh
approximates the geometry.
Can we have an option in preferences to show quadratic curved elements,
both
normal and rendered.
Can you clarify what the meaning of the mesh quality window is for
quadratic
elements? since it reports the same information irrespective of the
element
order (linear or quadratic).

Regards
Mark


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This e-mail may contain privileged/confidential information and may be
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it in error, please contact the sender by return e-mail or by
telephoning +44 (0)1480 302100.
Please then delete the e-mail and do not disclose its contents to any
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