octaviz-help

[Octaviz-help] How to use the vtk_trisurf function

[LUK S. <shu...@po...>]

Hello,

I do not quite understand the use of the vtk_trisurf. I tried this simple 2
triangle example - the unit square with a diagonal connecting (0,0) and (1,1).
The coordinates (x, y) and function values f are (columns vectors):

x=[0. 1. 0. 1.]'
y=[0. 0. 1. 1.]'
f=[1. 2. 3. 4.]'

and the triangulation is
tri=[1 2 3; 2 3 4]

Now using
vtk_trisurf(tri, x, y, f)

doesn't work. I got the error message

"error: number of rows must match (2 != 3) near line 149, column 27
error: evaluating postfix operator `'' near line 149, column 28
error: evaluating assignment expression near line 149, column 5
error: called from `vtk_trisurf' in file
`/usr/share/octave/site/m/octaviz/vtk_trisurf.m'"

I think I'm using the "4-parameter" method outlined in the online manual
"trisurf can be called with 2(3) or 4(5) parameters as trisurf(t,[x1 y1 z1; ...;
xn, yn, zn],(c)) or trisurf(t,[x1; ...; xn],[y1; ...; yn], [z1; ...; zn],(c))"

(It appears this is also the M**lab way to invoke trisurf according to their
online documentation.)

I'd be grateful if someone can provide a working snippet with this simple
example. IMHO, it'd be great if it's added to the online documentation.

Regards,
ST
--

Re: [Octaviz-help] How to use the vtk_trisurf function

[LUK S. <shu...@po...>]

LUK ShunTim wrote:
> Hello,
> 
> I do not quite understand the use of the vtk_trisurf. I tried this simple 2
> triangle example - the unit square with a diagonal connecting (0,0) and (1,1).

Sorry! The diagonal should be between (1,0) and (0,1).

> The coordinates (x, y) and function values f are (columns vectors):
> 
> x=[0. 1. 0. 1.]'
> y=[0. 0. 1. 1.]'
> f=[1. 2. 3. 4.]'
> 
> and the triangulation is
> tri=[1 2 3; 2 3 4]
> 
> Now using
> vtk_trisurf(tri, x, y, f)
> 
> doesn't work. I got the error message
> 
> "error: number of rows must match (2 != 3) near line 149, column 27
> error: evaluating postfix operator `'' near line 149, column 28
> error: evaluating assignment expression near line 149, column 5
> error: called from `vtk_trisurf' in file
> `/usr/share/octave/site/m/octaviz/vtk_trisurf.m'"
> 
> I think I'm using the "4-parameter" method outlined in the online manual
> "trisurf can be called with 2(3) or 4(5) parameters as trisurf(t,[x1 y1 z1; ...;
> xn, yn, zn],(c)) or trisurf(t,[x1; ...; xn],[y1; ...; yn], [z1; ...; zn],(c))"
> 
> (It appears this is also the M**lab way to invoke trisurf according to their
> online documentation.)
> 
> I'd be grateful if someone can provide a working snippet with this simple
> example. IMHO, it'd be great if it's added to the online documentation.
> 
> Regards,
> ST
> --

Re: [Octaviz-help] How to use the vtk_trisurf function

[Dragan T. <dra...@ul...>]

Apparently, there is a bug in vtk_trisurf that prevents you from rendering
surfaces that contain two triangles only. Try with four triangles (don't mind
overlaping triangles):

tri=[1 2 3; 2 3 4; 1 2 3; 2 3 4;]

Cheers,

Dragan

Selon LUK ShunTim <shu...@po...>, 13.11.2005:

> LUK ShunTim wrote:
> > Hello,
> >
> > I do not quite understand the use of the vtk_trisurf. I tried this simple 2
> > triangle example - the unit square with a diagonal connecting (0,0) and
> (1,1).
>
> Sorry! The diagonal should be between (1,0) and (0,1).
>
> > The coordinates (x, y) and function values f are (columns vectors):
> >
> > x=[0. 1. 0. 1.]'
> > y=[0. 0. 1. 1.]'
> > f=[1. 2. 3. 4.]'
> >
> > and the triangulation is
> > tri=[1 2 3; 2 3 4]
> >
> > Now using
> > vtk_trisurf(tri, x, y, f)
> >
> > doesn't work. I got the error message
> >
> > "error: number of rows must match (2 != 3) near line 149, column 27
> > error: evaluating postfix operator `'' near line 149, column 28
> > error: evaluating assignment expression near line 149, column 5
> > error: called from `vtk_trisurf' in file
> > `/usr/share/octave/site/m/octaviz/vtk_trisurf.m'"
> >
> > I think I'm using the "4-parameter" method outlined in the online manual
> > "trisurf can be called with 2(3) or 4(5) parameters as trisurf(t,[x1 y1 z1;
> ...;
> > xn, yn, zn],(c)) or trisurf(t,[x1; ...; xn],[y1; ...; yn], [z1; ...;
> zn],(c))"
> >
> > (It appears this is also the M**lab way to invoke trisurf according to
> their
> > online documentation.)
> >
> > I'd be grateful if someone can provide a working snippet with this simple
> > example. IMHO, it'd be great if it's added to the online documentation.
> >
> > Regards,
> > ST
> > --
>
>
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