[vtk-developers] New nonlinear celltypes
Soeren Gebbert
soeren.gebbert at inpro.de
Tue Jan 10 12:14:23 EST 2006
David C. Thompson wrote:
>On Mon, 2006-01-09 at 08:17, Soeren Gebbert wrote:
>
>
>>Im still developing the nonlinear cells. Tcl test running well. But i
>>still runing into a problem im not able to fix. I have implemented
>>contouring and clipping of the new cells. The methods for that are
>>quite similar. The contouring is working very well, but the clipping
>>produces strange output. I have attached some pictures of the
>>TriQuadraticHexahedron, to show you the point.
>>
>>
>Two questions:
>1. Could you send the LinearHexs array?
>2. Are the node numberings consistent with the figure below?
> 7 14 6
> +--------------+--------------+
> /: /: /|
> / : / : / |
> / : / : / |
> 15/ : 25/ : 13/ |
> +--------------+--------------+ |
> /: : / : /| |
> / : 19+......./....23+......./.|....+18
> / : .: / : / | /|
> 4/ : . : 12/ : 5/ | / |
> +--------------+--------------+ | / |
> | :. : | 26 : | |/ |
> | 20+ : | + : | 21+ |
> | .: : | 10: | /| |
> | . : 3+....|.........+....|../.|....+
> | . : . | . | / | / 2
> |. : . 22| . 17|/ | /
> 16 +--------------+--------------+ | /
> | :. | . | |/
> | 11+.........|.24.+.........|....+
> | . | . | / 9
> | . | . | /
> | . | . | /
> |. |. |/
> +--------------+--------------+
> 0 8 1
>
>Linear hexahedra should have nodes ordered like:
> {0,8,24,11,16,22,26,20}
>for example. I'll be glad to check the consistency of the array if you
>send it. If LinearHexs is the same as the array in
>vtkQuadraticHexahedron, then you must have the mid-face points ordered
>as shown above. I don't see anything wrong with the clipping routine.
>
>Also, the two routines you sent have this comment:
>
>
>> //clip each linear quad separately
>>
>>
> ^^^^ I assume you really mean hex here.
>
> David
>
>
>
>
Hi,
i choosed a different numbering:
7 14 6
+--------------+--------------+
/: /: /|
/ : / : / |
/ : / : / |
15/ : 25/ : 13/ |
+--------------+--------------+ |
/: : / : /| |
/ : 19+......./....22+......./.|....+18
/ : .: / : / | /|
4/ : . : 12/ : 5/ | / |
+--------------+--------------+ | / |
| :. : | 26 : | |/ |
| 23+ : | + : | 21+ |
| .: : | 10: | /| |
| . : 3+....|.........+....|../.|....+
| . : . | . | / | / 2
|. : . 20| . 17|/ | /
16 +--------------+--------------+ | /
| :. | . | |/
| 11+.........|.24.+.........|....+
| . | . | / 9
| . | . | /
| . | . | /
|. |. |/
+--------------+--------------+
0 8 1
I count the first 4 midface nodes against the clock. Thats a question of taste i think.
MyNumbering == YourNumbering
20 == 22
21 == 21
22 == 23
23 == 20
My linear hex's are:
static int LinearHexs[8][8] = {
{0, 8, 24, 11, 16, 20, 26, 23},
{8, 1, 9, 24, 20, 17, 21, 26},
{24, 9, 2, 10, 26, 21, 18, 22},
{11, 24, 10, 3, 23, 26, 22, 19},
{16, 20, 26, 23, 4, 12, 25, 15},
{20, 17, 21, 26, 12, 5, 13, 25},
{23, 26, 22, 19, 15, 25, 14, 7},
{26, 21, 18, 22, 25, 13, 6, 14}
};
I checked this many times, but maybe im blind, or i need better glases.
But anyway, i tried your numbering too, with the hope that this would
solve the problem, (i have two version of TriQuadraticHex)
but the clipping still dont work. :(
With the vtkBiQuadraticQuadraticWedge i have the same problems, and this
one has exactly
the same numbering like vtkQuadraticWedge:
//----------------------------------------------------------------------------
// We are using 8 linear wedge
static int LinearWedges[8][6] = { {0,6,8,12,15,17},
{6,7,8,15,16,17},
{6,1,7,15,13,16},
{8,7,2,17,16,14},
{12,15,17,3,9,11},
{15,16,17,9,10,11},
{15,13,16,9,4,10},
{17,16,14,11,10,5} };
The contouring always worked, independently if i used your numbering, or
my. Or if i interpolated the attributes or not!
No problems at all.
But the clipping never worked.
Maybe im seraching in the wrong direction? Maybe i made some mistakes
earlier?
Maybe the search directions from vtkCell3d::Clip has a problem with the
input?
Any suggestioins are welcome.
Thanks and best regards
Soeren
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