[GiDlist] Gauss points for tetrahedras. Postprocessing with

GiDList Archive 2002 - 2000
1

Hi there,
I have my results in the Gauss-Points
of a 3D mesh made of quadrilateral tetrahedras.
I have 24 gauss points placed at the boundary of each tetrahedra.
( 6 gauss points per face )
I guess that my GaussPoint definition block should be something like this :

GaussPoints “gauss_points_name” ElemType Tetrahedra
Number of Gauss Points: 24
Natural Coordinates : given
(***)
end gausspoints

Here are my questions :
1- what is the convention and the coordinate system used to give the natural coordinates in (***) ?
2- I notice that Kenji Furui reported a bug on Fri Sep 6 00:20:02 2002 when dealing with
4 gauss points in tetrahedras. I have GID 7.0 for linux, I wonder if this bug is already removed,
and if is there any patch fot this.

Thanks in advance
Andres


\

Andres B. Peratta
PhD Student
Wessex Institute of Technology
email: andres at wessex.ac.uk
TE: 44-(0)238-029-3239
Gate Cottage, Room3
Ashurst Lodge
Ashurst
Southampton (SO40-7AA)
UK

-------------- next part --------------
An HTML attachment was scrubbed…
URL: http://listas.cimne.upc.edu/pipermail/gidlist/attachments/20021004/d608a377/attachment.htm

2

hello,

  1. natural coordinates for triangles and tetrahedras are between 0.0 and 1.0,
    local to the element.
    for cuadrilaterals and hexahedras must be between -1.0 and 1.0
  2. the bug that Kenji Furui reported is solved and we are preparing a version
    to release it today or tomorrow.

miguel

Andres Peratta wrote:

Hi there,
I have my results in the Gauss-Points
of a 3D mesh made of quadrilateral tetrahedras.
I have 24 gauss points placed at the boundary of each tetrahedra.
( 6 gauss points per face )
I guess that my GaussPoint definition block should be something like this :
GaussPoints “gauss_points_name” ElemType Tetrahedra
Number of Gauss Points: 24
Natural Coordinates : given
(***)
end gausspoints
Here are my questions :
1- what is the convention and the coordinate system used to give the natural coordinates in (***) ?
2- I notice that Kenji Furui reported a bug on Fri Sep 6 00:20:02 2002 when dealing with
4 gauss points in tetrahedras. I have GID 7.0 for linux, I wonder if this bug is already removed,
and if is there any patch fot this.
Thanks in advance
Andres
–
Andres B. Peratta
PhD Student
Wessex Institute of Technology
email: andres at wessex.ac.uk
TE: 44-(0)238-029-3239
Gate Cottage, Room3
Ashurst Lodge
Ashurst
Southampton (SO40-7AA)
UK

Miguel A. de Riera Pasenau miguel at cimne.upc.es http://gid.cimne.upc.es

3

Dear Miguel,

It sounds like the beta version of GiD is being
updated very soon.
Please let us know if it becomes available.
I really appreciate for your quick work.

regards,

kenji furui
— “Miguel A. de Riera Pasenau” miguel at cimne.upc.es
wrote:
hello,
1. natural coordinates for triangles and tetrahedras
are between 0.0 and 1.0,
local to the element.
for cuadrilaterals and hexahedras must be between
-1.0 and 1.0
2. the bug that Kenji Furui reported is solved and
we are preparing a version
to release it today or tomorrow.
miguel
Andres Peratta wrote:
Hi there,
I have my results in the Gauss-Points
of a 3D mesh made of quadrilateral tetrahedras.
I have 24 gauss points placed at the boundary of
each tetrahedra.
( 6 gauss points per face )
I guess that my GaussPoint definition block should
be something like this :
GaussPoints “gauss_points_name” ElemType
Tetrahedra
Number of Gauss Points: 24
Natural Coordinates : given
(***)
end gausspoints
Here are my questions :
1- what is the convention and the coordinate
system used to give the natural coordinates in (***)
?
2- I notice that Kenji Furui reported a bug on
Fri Sep 6 00:20:02 2002 when dealing with
4 gauss points in tetrahedras. I have GID 7.0
for linux, I wonder if this bug is already removed,
and if is there any patch fot this.
Thanks in advance
Andres
–
Andres B. Peratta
PhD Student
Wessex Institute of Technology
email: andres at wessex.ac.uk
TE: 44-(0)238-029-3239
Gate Cottage, Room3
Ashurst Lodge
Ashurst
Southampton (SO40-7AA)
UK
–

Miguel A. de Riera Pasenau miguel at cimne.upc.es
http://gid.cimne.upc.es

GiDlist mailing list
GiDlist at gid.cimne.upc.es
_http://gid.cimne.upc.es/mailman/listinfo/gidlist_

Do you Yahoo!?
Faith Hill - Exclusive Performances, Videos & More
http://faith.yahoo.com

4

Hello:

I am currently trying to work on a mesh I have imported in GiD (the
original format is STL, but this has no importance).

Because the mesh was done with triangles, and my solver needs quads, I
would like to change the mesh. Although GiD provides some functions to
modify/delete elements, there does not seem to be provisions for the type
of work I am trying to do.

Furthermore, the geometry and mesh are two independent entities in GiD,
thus making it impossible to use the imported mesh to create a geometry
(which I could then re-mesh at will). Or at least, this is my current
impression.

I would like to know if anyone has worked on such a problem and come up
with a solution.

Thanks.

Philippe

5

You can import your mesh of triangles with Files-Import-Surf Mesh (from a
STL or GiD mesh ascii format file)
This read the mesh, and convert it to a pseudo-geometic entity, named
“surfmesh” in GiD (this is not a standard surface as a NURB, internally is
stored the shape of the underlying mesh). This “surfmesh” can be remeshed to
obtain the derided quadrilaterals.

Note: The meshing of a “surfmesh” can fail if the shape of the mesh is not
smooth.

Enrique
----- Original Message -----
From: “Philippe Bouchilloux” pb at magsoft-flux.com
To: “GiDList” gidlist at gatxan.cimne.upc.es
Sent: Friday, October 04, 2002 10:03 PM
Subject: [GiDlist] A mesh to geometry feature?


Hello:
I am currently trying to work on a mesh I have imported in GiD (the
original format is STL, but this has no importance).
Because the mesh was done with triangles, and my solver needs quads, I
would like to change the mesh. Although GiD provides some functions to
modify/delete elements, there does not seem to be provisions for the type
of work I am trying to do.
Furthermore, the geometry and mesh are two independent entities in GiD,
thus making it impossible to use the imported mesh to create a geometry
(which I could then re-mesh at will). Or at least, this is my current
impression.
I would like to know if anyone has worked on such a problem and come up
with a solution.
Thanks.
Philippe

GiDlist mailing list
GiDlist at gid.cimne.upc.es
_http://gid.cimne.upc.es/mailman/listinfo/gidlist_

6

Why doesn’t the Utilities version of Move work like the Geometry-Edit version which will move a singe point of a higher entity structure and then update the links? In a 3D model having to move a series of related points one point at a time rather than as a group is needlessly time consuming. Having to destroy all the higher entities first in order to use the Utilities version and then having to recreate the higher entities would be even worse.

-----Original Message-----
From: Enrique Escolano [SMTP:escolano at cimne.upc.es]
Sent: Friday, October 04, 2002 2:15 PM
To: gidlist at gatxan.cimne.upc.es
Subject: Re: [GiDlist] GiD 7.1, UtilitiesMove, Malfunction
This is not a bug, the utility move, create a copy of entities only if the selection cannot be moved because it is joined to another unselected entities (or exists higherentites).
If you select a group of isolated entities, then this entitites are only moved.
For example:
File: Move.gif
Regards
Enrique Escolano
----- Original Message -----
From: “LEWIS, RANDEL E” rlewis at oppd.com mailto:rlewis at oppd.com
To: gid at gatxan.cimne.upc.es mailto:gid at gatxan.cimne.upc.es&gt gidlist at gatxan.cimne.upc.es mailto:gidlist at gatxan.cimne.upc.es
Sent: Friday, October 04, 2002 8:19 PM
Subject: [GiDlist] GiD 7.1, UtilitiesMove, Malfunction

The Utility function “Move” in GiD 7.1 appears to behave the same as the “Copy” function. It creates new entities and does not reform the links to moved entities. This is a severe limitation when editing 3D models. Is there a work around or patch to fix this?
Randy

GiDlist mailing list
GiDlist at gid.cimne.upc.es mailto:GiDlist at gid.cimne.upc.es
_http://gid.cimne.upc.es/mailman/listinfo/gidlist_

7

The option “Move Point” not only apply a translation, also deform the
geometry.
This geometric deformation is a badly defined operation It can corrupt the
model
(if you deform moving a point, the lines must be also deformed, but the
interior of a surface
witn this contour lines is not able to be deformed on a compatible way).
This deformation, in general, only is valid for small displacements.

Enrique
----- Original Message -----
From: “LEWIS, RANDEL E” rlewis at oppd.com
To: gidlist at gatxan.cimne.upc.es
Sent: Monday, October 07, 2002 2:54 PM
Subject: RE: [GiDlist] GiD 7.1, UtilitiesMove, Malfunction


Why doesn’t the Utilities version of Move work like the Geometry-Edit
version which will move a singe point of a higher entity structure and then
update the links? In a 3D model having to move a series of related points
one point at a time rather than as a group is needlessly time consuming.
Having to destroy all the higher entities first in order to use the
Utilities version and then having to recreate the higher entities would be
even worse.

-----Original Message-----
From: Enrique Escolano [SMTP:escolano at cimne.upc.es]
Sent: Friday, October 04, 2002 2:15 PM
To: gidlist at gatxan.cimne.upc.es
Subject: Re: [GiDlist] GiD 7.1, UtilitiesMove, Malfunction
This is not a bug, the utility move, create a copy of entities only if
the selection cannot be moved because it is joined to another unselected
entities (or exists higherentites).

If you select a group of isolated entities, then this entitites are only
moved.

For example:
File: Move.gif
Regards
Enrique Escolano
----- Original Message -----
From: “LEWIS, RANDEL E” rlewis at oppd.com mailto:rlewis at oppd.com
To: gid at gatxan.cimne.upc.es mailto:gid at gatxan.cimne.upc.es&gt
gidlist at gatxan.cimne.upc.es mailto:gidlist at gatxan.cimne.upc.es
Sent: Friday, October 04, 2002 8:19 PM
Subject: [GiDlist] GiD 7.1, UtilitiesMove, Malfunction

The Utility function “Move” in GiD 7.1 appears to behave the same as
the “Copy” function. It creates new entities and does not reform the links
to moved entities. This is a severe limitation when editing 3D models. Is
there a work around or patch to fix this?

Randy

GiDlist mailing list
GiDlist at gid.cimne.upc.es mailto:GiDlist at gid.cimne.upc.es
_http://gid.cimne.upc.es/mailman/listinfo/gidlist_

GiDlist mailing list
GiDlist at gid.cimne.upc.es
_http://gid.cimne.upc.es/mailman/listinfo/gidlist_

8

Thanks for the explanation.

-----Original Message-----
From: Enrique Escolano [SMTP:escolano at cimne.upc.es]
Sent: Monday, October 07, 2002 9:10 AM
To: gidlist at gatxan.cimne.upc.es
Subject: Re: [GiDlist] GiD 7.1, UtilitiesMove, Malfunction
The option “Move Point” not only apply a translation, also deform the
geometry.
This geometric deformation is a badly defined operation It can corrupt the
model
(if you deform moving a point, the lines must be also deformed, but the
interior of a surface
witn this contour lines is not able to be deformed on a compatible way).
This deformation, in general, only is valid for small displacements.
Enrique
----- Original Message -----
From: “LEWIS, RANDEL E” rlewis at oppd.com
To: gidlist at gatxan.cimne.upc.es
Sent: Monday, October 07, 2002 2:54 PM
Subject: RE: [GiDlist] GiD 7.1, UtilitiesMove, Malfunction

Why doesn’t the Utilities version of Move work like the Geometry-Edit
version which will move a singe point of a higher entity structure and then
update the links? In a 3D model having to move a series of related points
one point at a time rather than as a group is needlessly time consuming.
Having to destroy all the higher entities first in order to use the
Utilities version and then having to recreate the higher entities would be
even worse.

9

Hi there:

Thanks for the tip regarding the import-surface_mesh feature. It seems to
work well.

The next step was to re-mesh the surfaces with quads. However, GiD does
not accept to do that with the pseudo-surfaces obtained (I get the error
message “Quadrilaterals not accepted for Surfmeshes”). The only solution I
found was to delete the pseudo-surfaces and create NURBS from the
lines. Is there a simpler way to go?

Thanks.

Philippe

10

You have reason, it is not implemented now the
quadrilaterals meshing of a “surfmesh”.

Enrique
----- Original Message -----
From: “Philippe Bouchilloux” pb at magsoft-flux.com
To: “GiDList” gidlist at gatxan.cimne.upc.es
Sent: Monday, October 07, 2002 4:36 PM
Subject: [GiDlist] Import-Surface_Mesh


Hi there:
Thanks for the tip regarding the import-surface_mesh feature. It seems
to
work well.
The next step was to re-mesh the surfaces with quads. However, GiD does
not accept to do that with the pseudo-surfaces obtained (I get the error
message “Quadrilaterals not accepted for Surfmeshes”). The only solution
I
found was to delete the pseudo-surfaces and create NURBS from the
lines. Is there a simpler way to go?
Thanks.
Philippe

GiDlist mailing list
GiDlist at gid.cimne.upc.es
_http://gid.cimne.upc.es/mailman/listinfo/gidlist_