[vtkusers] I think this is the problem......

John Platt jcplatt at lineone.net
Fri Mar 19 18:51:38 EST 2004


Jim,

Has your version of vtkDataSetSurfaceFilter got the following additions:

At about lines 886, 900 & 925

            outputCD->CopyData( cd, cellId, this->NumberOfNewCells++ );
            outputCD->CopyData( cd, cellId, this->NumberOfNewCells++ );
            outputCD->CopyData( cd, cellId, this->NumberOfNewCells++ );

John.

-----Original Message-----
From: vtkusers-admin at vtk.org [mailto:vtkusers-admin at vtk.org] On Behalf
Of James C. Robinson
Sent: 19 March 2004 18:47
To: goodwin.lawlor at ucd.ie
Cc: Vtk Users
Subject: RE: [vtkusers] I think this is the problem......

Goodwin,

Thanks for the tip. Stated in true gentlemanly style.

You know, given the most recent exchange on the can of worms that I have
opened, you would really wonder what way people think. I don't know
everybody else's occupation, but I am trying to scratch out a living and
build a small company and I don't even take all of this as seriously as
some
people do. Life is too short for people to get that upset about such
matters
(and ironically, it goes even further to back up my point - expressing
oneself in vtkisms to that extent smacks of "get a life").

Anyway, to give you an example of what I'm talking about (and I don't
expect
(nor want) an answer): I had a program that was working as designed in
v4.0.
I changed to v4.2 for the quad hexes, it didn't work perfectly.... Why?
I
used a vtkGeometryFilter all along and it worked, so why not now?
Anyway,
since there were subsequent patches etc. I discovered there were some
basic
access violations that Mr. Platt (I think) fixed. I downloaded and
recompiled the library. It didn't work quite right (Although the crash
was
gone), so I said: "Oh look. They have a v4.4 interim release. It does
double
precision (which I had wanted from the start) - I'll download that and
be
right up to date." I did. It crashed. I fixed the same access violation.
It
worked, but still didn't behave as it had originally in v4.0. I decided
to
go for the vtkDataSetSurfaceFilter. It crashed. I downloaded another
fixed
version. It still doesn't work.

Now for all you reading this who have been given the wrong impression by
other commentators on the continuing saga.... I did read the User's
Guide
(which I got with v3.2). It categorically will not help me with the
issue
that is going on in my program. I followed the examples to create the
pipelines that I use (where does one imagine I got them from???). The
fact
that an architecture can work in one version and then spontaneously
crashes
in the next release (of vtk) is a little outside my control (n'est
pas?).

Anyway, Goodwin, I myself am becoming a little jaded with these
exchanges
(phew, I hear a certain element sigh with relief). I only want solutions
(to
help create and benefit). I simply want to create a situation where we
all
minimise our effort to benefit from this great library (I would have
thought
that this was common sense). If I have made mistakes in my program
architecture, then I would like somewhere to post my "betises" under the
"How not to do it section". I was going to suggest to people who are in
the
same line as me (Finite Element Modelling) to think about clubbing
together.
Our needs are very specific and surely can be catered for by a small
subsets
of the overall vtk functionality. I could imagine the definition of a
basic
view (maybe MFC) view class for viewing an FE mesh (material) with a cut
plane, wireframe, a scalar and vector viewing functionality. Surely this
only has to be written once and anybody else could use it as a base
class
for writing their application specific interfaces?

My apologies if I have bored, upset or offended anyone.

Yours sincerely,

Jim

______________________

James C. Robinson, PhD,
Chartered Engineer,
Kepler Simulation Systems Ltd.,
42 Rivergrove,
Glanmire, Co. Cork,
Eire

Tel:         +353-21-4822028
Tel:         +353-87-2393010
Fax:        +353-21-4822028
E-mail:     j.robinson at kepler-systems.com
______________________

-----Original Message-----
From: Goodwin Lawlor [mailto:goodwin.lawlor at ucd.ie]
Sent: 19 March 2004 11:54
To: j.robinson at kepler-systems.com
Subject: RE: [vtkusers] I think this is the problem......

Hi Jim,

I hope my last mail didn't give the impression that I thought the vtk
documentation is ok... I just wanted to suggest some ways of getting the
best out of what is there. There is plenty of room for improvement. I
suppose kitware's response would be if you want high-level support you
have to buy a support contract. If you're a postgrad, you can spend the
time to learn vtk from the ground up. The mailing list used to be
better- its seems the list is a bit flooded now... They probably should
have a separate list just for installation problems.

If you're changing the opacity of a ugrid, you might consider volume
rendering your data. It's a new capability in vtk to be able to volume
render an unstructured grid. Have a look at the snappily named
vtkUnstructuredGridVolumeRayCastMapper. I'm not sure if vtk4.4 has the
class; vtk4.5 does though.

If you like, you can send me some test data and I'll do a quick
investigation into the problems you're seeing. I *really* have to get my
thesis out of the way, so can't promise any great shakes.

Good luck,

Goodwin

-----Original Message-----
From: James C. Robinson [mailto:j.robinson at kepler-systems.com]
Sent: 19 March 2004 00:24
To: goodwin.lawlor at ucd.ie
Cc: Vtk Users
Subject: RE: [vtkusers] I think this is the problem......


Goodwin,

Many thanks for the reply. You may have solved my particular technical
issue (its late, so I'll wait until morning to implement) but you have
also gone a long way to proving my point.

My request is not to have a step-by-step guide to every object in vtk,
the request is to have a step by step guide to a solution. Nobody (who
is not a developer is interested in the detail (although, as it stands,
the detail is what helps make the decisions). My particular issue (FE
blah di blah....) is common to an awful lot of people. I have received a
number (not huge, but
encouraging) of e-mails that support my point of view. It is probable
that the significance of the difference between similar filters is only
clear in a context (in the context of trying to achieve a particular
end). Your explanation of the relationship between the filters etc
pertinent to my case is quite clear and simply stated. I am not saying
that an entire picture of the library's functionality could be built up
overnight, but contributions such as yours in a sensible online format
would build into the documentation to which I would aspire.

Sincerely,

Jim
______________________

James C. Robinson, PhD,
Chartered Engineer,
Kepler Simulation Systems Ltd.,
42 Rivergrove,
Glanmire, Co. Cork,
Eire

Tel:         +353-21-4822028
Tel:         +353-87-2393010
Fax:        +353-21-4822028
E-mail:     j.robinson at kepler-systems.com
______________________






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