[vtkusers] Why are ther extra panels

[Jim Peterson]

All,
Somewhere along the line we managed to take this offline, The net result 
was it appears there are OpenGL artifacts generted when cappingon is set 
from the extrusion.

If anyone else on the list has any insight on this problem , I am sure 
there input would be appreciated.

Jim

Marc Jaspar wrote:
> You are absolutely correct.  I implicitly forced capping off ( 
> Extrusion->SetCapping(false); )  and the panels have disappeared.
> Good work.  It pays to ask sometimes.  
> Have a good weekend (at least what's left of it).
>
> Marc
>
> On Sun, Nov 7, 2010 at 1:36 PM, Jim Peterson <jimcp at cox.net 
> <mailto:jimcp at cox.net>> wrote:
>
>     Marc,
>     I generated the beam with CappingOff() and there are no extra end
>     panels, the interesting thing is the capping logic does not appear
>     to use triangles, that is when I have capping on, I cannot see any
>     triangle edges at the ends of the I Beam. the wireframe looks the
>     same for both the capped and uncapped versions.
>
>     Hope that helps,
>     Jim
>
>     Marc Jaspar wrote:
>
>         Thanks Jim.
>
>         Yes there are triangular panels and in some cases they are
>         rectangular closing the beam.  When you close in on the
>         geometry, the extra panels disappear (very strange).  I have
>         capped the geometry and no joy either.  I have generated the
>         shape clock wise, counter clock wise and it makes no
>         difference.  I have started the points in different order and
>         still no luck.
>         Very strange phenomenon.
>
>         Thanks for the help.  Maybe you could try just a rectangular
>         section (hollowed out of course) and see if it happens as well.
>
>         On Sun, Nov 7, 2010 at 12:50 PM, Jim Peterson <jimcp at cox.net
>         <mailto:jimcp at cox.net> <mailto:jimcp at cox.net
>         <mailto:jimcp at cox.net>>> wrote:
>
>            Marc Jaspar wrote:
>
>                Hi again Jim.
>
>                just for accuracy sakes, I have provided the extrusion code
>                (that you asked for)
>
>                //create the holding structure for the profile
>                vtkPolyData *Profile = vtkPolyData::New();
>                Profile->SetPoints(W21x101);
>                Profile->SetPolys(ShapeArray);
>
>                //createthe extrusion mechanism to extrute the profile
>                vtkLinearExtrusionFilter *Extrusion =
>                vtkLinearExtrusionFilter::New();
>
>                Extrusion->SetExtrusionTypeToVectorExtrusion();
>                Extrusion->SetVector(0.0, 0.0, 120.0);
>                Extrusion->SetCapping(true);
>                Extrusion->SetInput(Profile);
>
>
>                vtkPolyDataNormals *Norms = vtkPolyDataNormals::New();
>                Norms->SetInput(Extrusion->GetOutput());
>
>
>                as you can see, I used the Linear Extrusion to a vector
>         since
>                this is the way the structure is defined in my program.
>                It is a bit annoying since, all the calculations are
>         basically
>                done (very accurate) and I am now working on the display of
>                the model.
>
>
>                Thanks for your time.
>
>                Marc
>                On Sun, Nov 7, 2010 at 11:45 AM, Jim Peterson
>         <jimcp at cox.net <mailto:jimcp at cox.net>
>                <mailto:jimcp at cox.net <mailto:jimcp at cox.net>>
>         <mailto:jimcp at cox.net <mailto:jimcp at cox.net>
>
>                <mailto:jimcp at cox.net <mailto:jimcp at cox.net>>>> wrote:
>
>                   Marc Jaspar wrote:
>
>                       I am extruding a structural shape (a W21x101 as
>         an example)
>                       and, there are extra triangular end panels
>         displayed.
>                       I have capping on and off (as well) and they
>         still show up.
>                       If I zoom in, the extra panels disappear.  Why?
>                       Other than that, it works fine.
>
>                   Marc,
>                   excuse my ignorance, but what kind of algorithm are you
>                using to
>                   "extrude a structural shape"? and where would I find
>                W21x101 as an
>                   example of such a shape? Also, what version of vtk
>         are you
>                using,
>                   on what platform using what language?
>
>                   Thanks,
>                   Jim
>
>
>
>
>                --         Marc Jaspar
>
>                (905) 838-5978 (HOME)
>                (647) 982-5978 (CELL)
>
>                jaspar.marc at gmail.com <mailto:jaspar.marc at gmail.com>
>         <mailto:jaspar.marc at gmail.com <mailto:jaspar.marc at gmail.com>>
>                <mailto:jaspar.marc at gmail.com
>         <mailto:jaspar.marc at gmail.com> <mailto:jaspar.marc at gmail.com
>         <mailto:jaspar.marc at gmail.com>>>
>
>
>            Mark,
>            Thanks,
>            I am going to recreate this a piece at a time in Java on
>         windows
>            to see if I can find a bug (or feature as the case may be...)
>
>            The bitmap actually looks like the far ends of the i-beam are
>            closed with rectangles with one last triangle from the front
>            bottom to the far top corner. and they appear to be at both
>         ends.
>            I am going to start with 14 points for the h-beam, I am
>         also going
>            to create the points then the cell for the extrusion input
>         shape.
>            Thanks for the logic. Let me see what I get...
>
>            Jim
>
>
>
>
>         -- 
>         Marc Jaspar
>
>         (905) 838-5978 (HOME)
>         (647) 982-5978 (CELL)
>
>         jaspar.marc at gmail.com <mailto:jaspar.marc at gmail.com>
>         <mailto:jaspar.marc at gmail.com <mailto:jaspar.marc at gmail.com>>
>
>
>
>
>
> -- 
> Marc Jaspar
>
> (905) 838-5978 (HOME)
> (647) 982-5978 (CELL)
>
> jaspar.marc at gmail.com <mailto:jaspar.marc at gmail.com>
>