| Create DXF file out of vertices and connectivities [message #39913] |
Fri, 25 June 2004 14:25  |
Tukee10
Messages: 7
Registered: June 2004
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Junior Member |
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Hello,
I have following problem: I created the mesh structure of a volume with
INTERVAL_VOLUME, which gives me vertices (3,n) and connectivities (1,m).
When I display it with XOBJVIEW, I get a wonderful 3d structure. How do I
create a DXF file that contains the mesh structure ?
I know that it works with an IDLffDXF object. I tried that with following
code:
ptr_verts = ptr_new(Verts)
ptr_conn = ptr_new(Conn)
oDXF = OBJ_NEW('IDLffDXF')
poly = {IDL_DXF_POLYGON}
poly.vertices = ptr_verts
poly.connectivity = ptr_conn
poly.dxf_type = 10
oDXF->PutEntity, poly
IF (not oDXF->Write('Mesh_Model.dxf')) THEN PRINT, 'Write Failed.'
OBJ_DESTROY, oDXF
It creates a DXF file, but when I open the file with AutoCAD, it seems to
connect all the point in a strange way.
Is there anyone who has an idea ?
Thanks,
Tukee.
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| Re: Create DXF file out of vertices and connectivities [message #39971 is a reply to message #39913] |
Tue, 29 June 2004 14:26  |
Karl Schultz
Messages: 341
Registered: October 1999
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Senior Member |
|
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"Dick Jackson" <dick@d-jackson.com> wrote in message
news:B78Ec.933959$oR5.650290@pd7tw3no...
> [Please ignore my previous post, I improved my testing code for clarity]
>
> "Karl Schultz" <kschultz_no_spam@rsinc.com> wrote in message
> news:<10e0jrc69hn5715@corp.supernews.com>...
>>
>> "Tukee10" <turgutkaracay@hotmail.com> wrote in message
>>
>
news:e6feeb9d9fa4d9dad40235e15f6ab40b@localhost.talkaboutpro gramming.com...
>>> Hello,
>>> I have following problem: I created the mesh structure of a volume
> with
>>> INTERVAL_VOLUME, which gives me vertices (3,n) and connectivities
> (1,m).
>>> When I display it with XOBJVIEW, I get a wonderful 3d structure. How
> do I
>>> create a DXF file that contains the mesh structure ?
>>> I know that it works with an IDLffDXF object.
> [...]
>>> It creates a DXF file, but when I open the file with AutoCAD, it
> seems to
>>> connect all the point in a strange way.
>>> Is there anyone who has an idea ?
>>
>> INTERVAL_VOLUME returns a list of vertices and a connectivity list
> that
>> represents tetrahedra (3D pyramid-like objects). If you used this
> vertex
>> list and this connectivity list to create an IDLgrPolygon that you
> then
>> displayed in XOBJVIEW, you should have seen quite a mess - or you got
> very
>> lucky.
>>
>> You should use TETRA_SURFACE [...]
>
> "Tukee10" <turgutkaracay@hotmail.com> wrote in message
>
news:2d0234904ddaf48a12f5006bb0ae4bdb@localhost.talkaboutpro gramming.com...
>> Thank you for your response.
>> I forgot to add, that I`m using TETRA_SURFACE to display in XOBJVIEW,
>> which worked quite well. It displays the mesh structure I want, but
> when I
>> write a DXF file, the mesh looks weird when I open it with AutoCAD. Is
>> IDL_DXF_POLYGON the right structure format, if yes, does the DXF_TYPE
> has
>> to be 10 and are there other parameters to consider ?
>
> Hi Tukee, Karl,
>
> I tried this out too, and indeed it seems the file is mucked up. It does
> look like a DXF writing bug to me. If you want to look further, here's
> what I did:
>
> =====
>
> PRO WriteDXFTest
>
> ;; Make a surface (from online help for Interval_Volume)
>
> RESTORE, FILEPATH('clouds3d.dat', $
> SUBDIRECTORY=['examples','data'])
> INTERVAL_VOLUME, rain, 0.1, 0.6, verts, conn
> conn = TETRA_SURFACE(verts, conn)
> ; oRain = OBJ_NEW('IDLgrPolygon', verts, POLYGONS=conn, $
> ; COLOR=[255,255,255], SHADING=1)
> ; XOBJVIEW, oRain, BACKGROUND=[150,200,255]
>
> ;; Simplify mesh
>
> ntri=mesh_decimate(verts,conn,connout,vertices=vertsdec, $
> percent_poly=10)
> verts=vertsdec
> conn=connout
>
> polyColor = [255, 0, 0]
> dxfFile = 'Mesh_Model.dxf'
> XObjView, Obj_New('IDLgrPolygon', verts, Polygons=conn, $
> Color=polyColor), $
> Title='IDLgrPolygon Made From Raw Data'
>
> ;; From Tukee10
>
> ptr_verts = ptr_new(Verts)
> ptr_conn = ptr_new(Conn)
>
> oDXF = OBJ_NEW('IDLffDXF')
> poly = {IDL_DXF_POLYGON}
> poly.vertices = ptr_verts
> poly.connectivity = ptr_conn
> poly.dxf_type = 10
>
> oDXF->PutEntity, poly
> IF (not oDXF->Write(dxfFile)) THEN PRINT, 'Write Failed.'
> OBJ_DESTROY, oDXF
>
> ;; Try it out
>
> oModel = Get_DXF_Objects(dxfFile)
> oDXFRead = oModel -> Get(/All) ; IDLgrPolygon
> oModel -> Remove, /All
>
> ;; Vert_Colors are all black, change color to
> ;; something more visible
> oDXFRead -> SetProperty, Vert_Colors=-1, Color=polyColor
> XObjView, oDXFRead, Title='Read From DXF File'
>
> END ; WriteDXFTest
>
> =====
>
> ... it looks like mostly-correct points are being joined up in a
> haphazard way, with a lot of joining of points in sequence along x and
> y.
>
> Are we missing something in the DXF writing?
>
Well, yes and no.
A dxf_type code of 10 is DXF FACE3D, which is a 4-vertex polygon. I think
that IDL will still try to write FACE3D entities if you use this code even
though your data isn't arranged this way. This will lead to incorrect, or
at least, unintended output in your dxf file. The DXF heart example that
ships with IDL contains FACE3D entities, and this might lead some to try to
use this code to write entities. I think that if you had a bunch of
4-vertex polygons, a code of 10 would work.
You can try a code of 9 (polygon). Yes, I know that the IDL docs don't say
that 9 is valid for a IDL_DXF_POLYGON structure, but it is. IDL actually
ends up generating DXF POLYLINE entities with the appropriate settings to
indicate that it is a polyface mesh.
That being said, if you use code 9, IDL will run your polygons through the
tessellator. I believe that this is done to make sure that the mesh is a
simple triangle mesh that is appropriate for the DXF polyface mesh. The
trouble is that your output from ISOSURFACE, INTERVAL_VOLUME/TETRA_SURFACE,
and many other routines are already lists of triangles. Running them
through the tessellator is not necessary and in fact can mess up the mesh.
I'm not sure right now why the mesh gets corrupted. I'm looking in to it.
IDL should really avoid the tessellation if it can. (We have an open
problem report related to this)
Karl
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| Re: Create DXF file out of vertices and connectivities [message #39992 is a reply to message #39913] |
Mon, 28 June 2004 23:38 |
Dick Jackson
Messages: 347
Registered: August 1998
|
Senior Member |
|
|
[Please ignore my previous post, I improved my testing code for clarity]
"Karl Schultz" <kschultz_no_spam@rsinc.com> wrote in message
news:<10e0jrc69hn5715@corp.supernews.com>...
>
> "Tukee10" <turgutkaracay@hotmail.com> wrote in message
>
news:e6feeb9d9fa4d9dad40235e15f6ab40b@localhost.talkaboutpro gramming.com...
>> Hello,
>> I have following problem: I created the mesh structure of a volume
with
>> INTERVAL_VOLUME, which gives me vertices (3,n) and connectivities
(1,m).
>> When I display it with XOBJVIEW, I get a wonderful 3d structure. How
do I
>> create a DXF file that contains the mesh structure ?
>> I know that it works with an IDLffDXF object.
[...]
>> It creates a DXF file, but when I open the file with AutoCAD, it
seems to
>> connect all the point in a strange way.
>> Is there anyone who has an idea ?
>
> INTERVAL_VOLUME returns a list of vertices and a connectivity list
that
> represents tetrahedra (3D pyramid-like objects). If you used this
vertex
> list and this connectivity list to create an IDLgrPolygon that you
then
> displayed in XOBJVIEW, you should have seen quite a mess - or you got
very
> lucky.
>
> You should use TETRA_SURFACE [...]
"Tukee10" <turgutkaracay@hotmail.com> wrote in message
news:2d0234904ddaf48a12f5006bb0ae4bdb@localhost.talkaboutpro gramming.com...
> Thank you for your response.
> I forgot to add, that I`m using TETRA_SURFACE to display in XOBJVIEW,
> which worked quite well. It displays the mesh structure I want, but
when I
> write a DXF file, the mesh looks weird when I open it with AutoCAD. Is
> IDL_DXF_POLYGON the right structure format, if yes, does the DXF_TYPE
has
> to be 10 and are there other parameters to consider ?
Hi Tukee, Karl,
I tried this out too, and indeed it seems the file is mucked up. It does
look like a DXF writing bug to me. If you want to look further, here's
what I did:
=====
PRO WriteDXFTest
;; Make a surface (from online help for Interval_Volume)
RESTORE, FILEPATH('clouds3d.dat', $
SUBDIRECTORY=['examples','data'])
INTERVAL_VOLUME, rain, 0.1, 0.6, verts, conn
conn = TETRA_SURFACE(verts, conn)
; oRain = OBJ_NEW('IDLgrPolygon', verts, POLYGONS=conn, $
; COLOR=[255,255,255], SHADING=1)
; XOBJVIEW, oRain, BACKGROUND=[150,200,255]
;; Simplify mesh
ntri=mesh_decimate(verts,conn,connout,vertices=vertsdec, $
percent_poly=10)
verts=vertsdec
conn=connout
polyColor = [255, 0, 0]
dxfFile = 'Mesh_Model.dxf'
XObjView, Obj_New('IDLgrPolygon', verts, Polygons=conn, $
Color=polyColor), $
Title='IDLgrPolygon Made From Raw Data'
;; From Tukee10
ptr_verts = ptr_new(Verts)
ptr_conn = ptr_new(Conn)
oDXF = OBJ_NEW('IDLffDXF')
poly = {IDL_DXF_POLYGON}
poly.vertices = ptr_verts
poly.connectivity = ptr_conn
poly.dxf_type = 10
oDXF->PutEntity, poly
IF (not oDXF->Write(dxfFile)) THEN PRINT, 'Write Failed.'
OBJ_DESTROY, oDXF
;; Try it out
oModel = Get_DXF_Objects(dxfFile)
oDXFRead = oModel -> Get(/All) ; IDLgrPolygon
oModel -> Remove, /All
;; Vert_Colors are all black, change color to
;; something more visible
oDXFRead -> SetProperty, Vert_Colors=-1, Color=polyColor
XObjView, oDXFRead, Title='Read From DXF File'
END ; WriteDXFTest
=====
... it looks like mostly-correct points are being joined up in a
haphazard way, with a lot of joining of points in sequence along x and
y.
Are we missing something in the DXF writing?
Cheers,
--
-Dick
Dick Jackson / dick@d-jackson.com
D-Jackson Software Consulting / http://www.d-jackson.com
Calgary, Alberta, Canada / +1-403-242-7398 / Fax: 241-7392
|
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| Re: Create DXF file out of vertices and connectivities [message #39994 is a reply to message #39913] |
Mon, 28 June 2004 23:15 |
Dick Jackson
Messages: 347
Registered: August 1998
|
Senior Member |
|
|
"Karl Schultz" <kschultz_no_spam@rsinc.com> wrote in message
news:<10e0jrc69hn5715@corp.supernews.com>...
>
> "Tukee10" <turgutkaracay@hotmail.com> wrote in message
>
news:e6feeb9d9fa4d9dad40235e15f6ab40b@localhost.talkaboutpro gramming.com...
>> Hello,
>> I have following problem: I created the mesh structure of a volume
with
>> INTERVAL_VOLUME, which gives me vertices (3,n) and connectivities
(1,m).
>> When I display it with XOBJVIEW, I get a wonderful 3d structure. How
do I
>> create a DXF file that contains the mesh structure ?
>> I know that it works with an IDLffDXF object.
[...]
>> It creates a DXF file, but when I open the file with AutoCAD, it
seems to
>> connect all the point in a strange way.
>> Is there anyone who has an idea ?
>
> INTERVAL_VOLUME returns a list of vertices and a connectivity list
that
> represents tetrahedra (3D pyramid-like objects). If you used this
vertex
> list and this connectivity list to create an IDLgrPolygon that you
then
> displayed in XOBJVIEW, you should have seen quite a mess - or you got
very
> lucky.
>
> You should use TETRA_SURFACE [...]
"Tukee10" <turgutkaracay@hotmail.com> wrote in message
news:2d0234904ddaf48a12f5006bb0ae4bdb@localhost.talkaboutpro gramming.com...
> Thank you for your response.
> I forgot to add, that I`m using TETRA_SURFACE to display in XOBJVIEW,
> which worked quite well. It displays the mesh structure I want, but
when I
> write a DXF file, the mesh looks weird when I open it with AutoCAD. Is
> IDL_DXF_POLYGON the right structure format, if yes, does the DXF_TYPE
has
> to be 10 and are there other parameters to consider ?
Hi Tukee, Karl,
I tried this out too, and indeed it seems the file is mucked up. It does
look like a DXF writing bug to me. If you want to look further, here's
what I did:
=====
PRO WriteDXFTest
;; From online help for Interval_Volume
RESTORE, FILEPATH('clouds3d.dat', $
SUBDIRECTORY=['examples','data'])
INTERVAL_VOLUME, rain, 0.1, 0.6, verts, conn
conn = TETRA_SURFACE(verts, conn)
; oRain = OBJ_NEW('IDLgrPolygon', verts, POLYGONS=conn, $
; COLOR=[255,255,255], SHADING=1)
; XOBJVIEW, oRain, BACKGROUND=[150,200,255]
;; Simplify mesh
ntri=mesh_decimate(verts,conn,connout,vertices=vertsdec,perc ent_poly=10)
verts=vertsdec
conn=connout
;; From Tukee10
ptr_verts = ptr_new(Verts)
ptr_conn = ptr_new(Conn)
oDXF = OBJ_NEW('IDLffDXF')
poly = {IDL_DXF_POLYGON}
poly.vertices = ptr_verts
poly.connectivity = ptr_conn
poly.dxf_type = 10
oDXF->PutEntity, poly
IF (not oDXF->Write('Mesh_Model.dxf')) THEN PRINT, 'Write Failed.'
OBJ_DESTROY, oDXF
;; Try it out
oModel = Get_DXF_Objects('Mesh_Model.dxf')
oDXFRead = oModel -> Get(/All) ; IDLgrPolygon
oModel -> Remove, /All
XObjView, oDXFRead
END ; WriteDXFTest
=====
... it looks like mostly-correct points are being joined up in a
haphazard way, with a lot of joining of points in sequence along x and
y.
Are we missing something in the DXF writing?
Cheers,
--
-Dick
Dick Jackson / dick@d-jackson.com
D-Jackson Software Consulting / http://www.d-jackson.com
Calgary, Alberta, Canada / +1-403-242-7398 / Fax: 241-7392
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| Re: Create DXF file out of vertices and connectivities [message #39999 is a reply to message #39913] |
Mon, 28 June 2004 10:50 |
Tukee10
Messages: 7
Registered: June 2004
|
Junior Member |
|
|
Thank you for your response.
I forgot to add, that I`m using TETRA_SURFACE to display in XOBJVIEW,
which worked quite well. It displays the mesh structure I want, but when I
write a DXF file, the mesh looks weird when I open it with AutoCAD. Is
IDL_DXF_POLYGON the right structure format, if yes, does the DXF_TYPE has
to be 10 and are there other parameters to consider ?
Thanks,
Tukee.
|
|
|
|
| Re: Create DXF file out of vertices and connectivities [message #40000 is a reply to message #39913] |
Mon, 28 June 2004 10:04 |
Karl Schultz
Messages: 341
Registered: October 1999
|
Senior Member |
|
|
"Tukee10" <turgutkaracay@hotmail.com> wrote in message
news:e6feeb9d9fa4d9dad40235e15f6ab40b@localhost.talkaboutpro gramming.com...
> Hello,
> I have following problem: I created the mesh structure of a volume with
> INTERVAL_VOLUME, which gives me vertices (3,n) and connectivities (1,m).
> When I display it with XOBJVIEW, I get a wonderful 3d structure. How do I
> create a DXF file that contains the mesh structure ?
> I know that it works with an IDLffDXF object. I tried that with following
> code:
>
> ptr_verts = ptr_new(Verts)
> ptr_conn = ptr_new(Conn)
>
> oDXF = OBJ_NEW('IDLffDXF')
> poly = {IDL_DXF_POLYGON}
> poly.vertices = ptr_verts
> poly.connectivity = ptr_conn
> poly.dxf_type = 10
>
> oDXF->PutEntity, poly
> IF (not oDXF->Write('Mesh_Model.dxf')) THEN PRINT, 'Write Failed.'
> OBJ_DESTROY, oDXF
>
> It creates a DXF file, but when I open the file with AutoCAD, it seems to
> connect all the point in a strange way.
> Is there anyone who has an idea ?
INTERVAL_VOLUME returns a list of vertices and a connectivity list that
represents tetrahedra (3D pyramid-like objects). If you used this vertex
list and this connectivity list to create an IDLgrPolygon that you then
displayed in XOBJVIEW, you should have seen quite a mess - or you got very
lucky.
You should use TETRA_SURFACE to create a polygonal surface from the tet mesh
that you can then display in XOBJVIEW and put into DXF.
So, if INTERVAL_VOLUME returns Verts and Conn, then
NewConn = TETRA_SURFACE(Verts, Conn)
XOBJVIEW, OBJ_NEW('IDLgrPolygon', Verts, POLYGONS=NewConn....
ptr_verts = ptr_new(Verts)
ptr_conn = ptr_new(NewConn)
oDXF = OBJ_NEW('IDLffDXF')
poly = {IDL_DXF_POLYGON}
poly.vertices = ptr_verts
poly.connectivity = ptr_conn
poly.dxf_type = 10
oDXF->PutEntity, poly
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