2004-august.txt

acis说明文档

From alittleshrimp at gmail.com  Sun Aug  1 10:54:20 2004
From: alittleshrimp at gmail.com ([e-mail])
Date: Sun Aug  1 10:54:33 2004
Subject: [Acis-alliance] How to display a STL model using ACIS?
Message-ID: <[e-mail]>

Hi, I want to know how to display a STL model using ACIS. Does anyone
know how to do it?
Thanks for your help!

-- 
shrimp
From alittleshrimp at gmail.com  Mon Aug  2 09:35:54 2004
From: alittleshrimp at gmail.com ([e-mail])
Date: Mon Aug  2 09:36:13 2004
Subject: [Acis-alliance] How to display a STL model using ACIS?
Message-ID: <[e-mail]>

Hi, I'm a new learner. Now I want to display a STL model using ACIS,
but I really doesn't know how to do it. Anyone could give me some
suggestions?
Thanks for your help!
-- 
shrimp
From emxmns at nottingham.ac.uk  Mon Aug  2 12:30:36 2004
From: emxmns at nottingham.ac.uk (Martin Sherburn)
Date: Mon Aug  2 12:31:39 2004
Subject: [Acis-alliance] Re: How to display a STL model using ACIS?
Message-ID: <[e-mail]>

Hi,

STL files are a list of triangles strung together which form a closed surface. ACIS does not function in the same way, if all you are interested in is displaying the model. I suggest you look into writing an OpenGL application which would read and display the STL data directly. It would be a very easy task once you have got your OpenGL window initialised and ready to render to.

If you need a discription of the STL file format you can look on the internet for it, there are plenty of resources for that. If you can't find any then i'll give you a link.

Martin.
-------------------------------------------------------------
Hi, I'm a new learner. Now I want to display a STL model using ACIS,
but I really doesn't know how to do it. Anyone could give me some
suggestions?
Thanks for your help!
-- 
shrimp
-------------------------------------------------------------


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University of Nottingham may be monitored as permitted by UK legislation.


From zhengshu.shen at asu.edu  Tue Aug  3 01:02:35 2004
From: zhengshu.shen at asu.edu (shen)
Date: Tue Aug  3 01:12:31 2004
Subject: [Acis-alliance] help on attribute retrieval
Message-ID: <[e-mail]>

Hello!
i got a problem in retriveing attribute attached. Pls see the following
code:

 ENTITY *en = .....;

 new ATTRIB_GEN_INTEGER(en,"REAL", 123);

----------------block 1----------------
 NAMED_ATTRIB *REALattrib = find_named_attribute(en,"REAL");
 if(REALattrib == NULL)
     AfxMessageBox("no attribute is found!");
 else
      fout << "value = "
             << ((ATTRIB_GEN_INTEGER*)REALattrib)->value();

----------------block 2----------------
 int geom =
((ATTRIB_GEN_INTEGER*)find_named_attrib(en,"REAL"))->value();
 fout << "value = " << geom;

Block 2 always give the correct value, which is 123 (integer).
But Block 1 does not work! REALattrib always got "NULL" value, how come
a NULL pointer can casted (as used in Block 2) to ATTRIB_GEN_INTEGER*
and then successfully return the value?

Thanks a lot.

Shen
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From lkoky_my at yahoo.com  Tue Aug  3 03:57:16 2004
From: lkoky_my at yahoo.com (KY Lee)
Date: Tue Aug  3 03:57:32 2004
Subject: [Acis-alliance] Generic Attributes Usages
Message-ID: <[e-mail]>

Hi there,

In our program, we add some generic char* attribute to
acis entity for extra info using 
   api_add_generic_named_attribute(entity, "SModel",
labstring);

and then retrieve them using the code snippet below

The question I have now, is whether the way I retrieve
the atttrib is the right way? or any other more
typesafe way to do this?

The static cast from ATTRIB_GEN_NAME* to
ATTRIB_GEN_STRING* is particularly vulnerable.

any other suggestions?

/***********************************************************/
ATTRIB_GEN_NAME *attr; 
api_find_named_attribute(entity, "SModel", attr);
//  if this entity has been previous tagged with
SModel attribute
if(attr)
{
     ATTRIB_GEN_STRING * attrib = (ATTRIB_GEN_STRING
*)(attr);
     const char* labstring = attrib->value();
     //
     //  do Something
}
/************************************************************/


ths in advance.


		
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From Samuel.Mazel at cedrat.com  Wed Aug  4 10:44:35 2004
From: Samuel.Mazel at cedrat.com (Samul Mazel)
Date: Wed Aug  4 10:41:49 2004
Subject: [Acis-alliance] Merge similar face in a Body ?
Message-ID: <001701c47a31$8fac33b0$[e-mail]>

Hello,

I have a little problem, in a body i have two faces with same vertex and
edges, I want to make an operation to obtain only one, and I want to keep
one.
With a check I have this :

acis> (entity:set-color (part:load "D:/Mazel_Samuel/Project1/res.sat" )
GREEN)
()
acis> (entity:check (entity 1))

entid  73082120: Error: duplicate vertex
 at 5.000000000000 -2.000000000000 -2.000000000000
        other vertex is 73763912
entid  73081784: Error: duplicate vertex
 at 5.000000000000 2.000000000000 -2.000000000000
        other vertex is 73765208
entid  73081448: Error: duplicate vertex
 at 5.000000000000 -2.000000000000 2.000000000000
        other vertex is 73763528
entid  73766936: Error: duplicate vertex
 at 5.000000000000 2.000000000000 2.000000000000
        other vertex is 73766792
entid  73079816: Error: duplicate vertex
 at -5.000000000000 2.000000000000 -2.000000000000
        other vertex is 73764632
entid  73080824: Error: duplicate vertex
 at -5.000000000000 -2.000000000000 -2.000000000000
        other vertex is 73765736
entid  73764776: Error: duplicate vertex
 at -5.000000000000 2.000000000000 2.000000000000
        other vertex is 73763480
entid  73765592: Error: duplicate vertex
 at -5.000000000000 -2.000000000000 2.000000000000
        other vertex is 73764296

checked:
        3 lumps
        3 shells
        0 wires
        20 faces
        22 loops
        88 coedges
        44 edges
        32 vertices
(#[entity 2 25] #[entity 3 25] #[entity 4 25] #[entity 5 25] #[entity 6 25]
#[entity 7 25]
 #[entity 8 25] #[entity 9 25])
I want 18 Faces 20 loops 36 edges and 26 vertices
What you suggest ?
thanks
Samuel

From emxmns at nottingham.ac.uk  Wed Aug  4 12:39:36 2004
From: emxmns at nottingham.ac.uk (Martin Sherburn)
Date: Wed Aug  4 12:40:11 2004
Subject: [Acis-alliance] Stitching faces of seperate entities
Message-ID: <[e-mail]>

Hello,

I'll start off by explaining what it is that i'm trying to do:

I start out with a solid block entity, then a create a number of thin cylindrical shaped volumes that go through the block.
I then subtract the cylinders from the block, leaving a block full of holes. But I still keep a copy of the cylinders, and intersect them with the original block so that the cylinders do not extend out past the boundaries of the block.

So essentially what i end up with is the same as what i started with, a block. But the block is seperated into several volumes: The block with the holes in it, and the trimmed cylinders. Now what i would like to do is to be able to stitch the internal faces of the block with the external faces of the cylinders. So that I only have one face between the boundaries of the cylinders and the block.

What function should i use to do this? I have tried using api_stitch, passing in the list of entities i have. but it doesn't seem to do the job!

The reason I want to do this is because I will use the model to mesh it using another peice of software, and use the mesh to perform finite element simulations. And in order to get a valid mesh from this other software, i need the faces to be the same or the nodes at the boundaries will not coincide.

Any help would be greatly appreciated,

Thank you,

Martin.


This message has been scanned but we cannot guarantee that it and any
attachments are free from viruses or other damaging content: you are
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From alames at sandia.gov  Wed Aug  4 15:50:47 2004
From: alames at sandia.gov (Ames, Arlo)
Date: Wed Aug  4 15:51:48 2004
Subject: [Acis-alliance] How to obtain a pcurve?
Message-ID: <[e-mail]>

I've been out...

The sg_add_pcurve functions compute a pcurve- that is, a curve of one
parameter, t, that maps to two dimensions, u, and v, which are parameter
values on the face that underlies the curve.  In order to do this, the
function asks the edge for it's coedge's loop's face's surface in order to
know what u,v parameterization the pcurve maps to.  If the coedge doesn't
lie in a face (that is, has a LOOP which has a FACE which has a SURFACE),
you don't get a pcurve.  Your ACIS_NEW COEDGE... code merely creates the
coedge, without placing it on a FACE.  Ergo, nothing happens.  Create the
other structure and you'll have your pcurve.

Note that pcurve creation is iterative -- it steps points along the curve,
does closest_point_on_surface, and computes u,v parameters.  This can take a
lot of time if the curve doesn't fit the surface very well.

Arlo Ames
[e-mail]

-----Original Message-----
From: Kc wu [mailto:[e-mail]] 
Sent: Thursday, July 29, 2004 7:47 AM
To: [e-mail]
Subject: [Acis-alliance] How to obtain a pcurve?


Dear ACIS-Alliance,
I too want to obtain a pcurve from the curve generated
by api_project_curve_to_surface(). 
I tried sg_add_pcurve_to_coedge(COEDGE*) as followed:
 
API_BEGIN
    EDGE* projected_edge = funcReturnProjectEdge();
    COEDGE *co = ACIS_NEW COEDGE(projected_edge,
FORWARD, NULL, NULL);
    sg_add_pcurve_to_coedge(co);
    
    PCURVE* Pcurve_m = co->geometry();
    if(Pcurve_m) //Pcurve_m is still NULL!!!!!!!!!
         pcurve* pcur =
Pcurve_m->equation().deep_copy();
API_END
 
The PCURVE acquired from the COEDGE is still NULL.
 
Thanks for your help,
 
Kuo-Cheng

    
>Alex,

>sg_add_pcurve_to_coedge(COEDGE*) does it.

>Hari

At 12:43 PM -0500 11/12/03, Alexander Muthler wrote:
>Dear ACIS-Alliance,
>
>when I project a curve to a surface via the
>api_project_curve_to_surface(...)   function, the
returned curve has no
>pcurve.
>Does anybody know, how to compute resp. add the
pcurve to the curve or
>coedge?
>
>Your help would be appreciated.
>
>Best Regards,
>Alex



		
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From alames at sandia.gov  Wed Aug  4 16:19:57 2004
From: alames at sandia.gov (Ames, Arlo)
Date: Wed Aug  4 16:20:23 2004
Subject: [Acis-alliance] Re: How to display a STL model using ACIS?
Message-ID: <[e-mail]>

We have written software in the past to create ACIS representations of STL
data.  Not for visualization, but for other reasons.  Yes, it is very
inefficient to create an ACIS representation, unless the facetization is the
only form the data exists in.  But it is, technically, possible.  I concur
with Martin that unless you REALLY need it, facets are more easily managed
on their own.

Creating an ACIS representation of STL data isn't at all difficult.  There
are a variety of ways to write it, but in the end each facet becomes a face
and you need to stitch all the faces together to form a solid.  Blindly
calling api_stitch does work, but it can take quite a while if you have
really big STL files.  I won't go into the details of which functions to
call to create planar faces, but you can either use the direct interface
calls (e.g. new APOINT, new LINE, new PLANE, new VERTEX, new EDGE, new
COEDGE, new LOOP, new FACE) or api calls (api_make_ewire, api_cover_wires)
or some combination.

Arlo Ames
[e-mail]

-----Original Message-----
From: Martin Sherburn [mailto:[e-mail]] 
Sent: Monday, August 02, 2004 10:31 AM
To: [e-mail]
Subject: [Acis-alliance] Re: How to display a STL model using ACIS?


Hi,

STL files are a list of triangles strung together which form a closed
surface. ACIS does not function in the same way, if all you are interested
in is displaying the model. I suggest you look into writing an OpenGL
application which would read and display the STL data directly. It would be
a very easy task once you have got your OpenGL window initialised and ready
to render to.

If you need a discription of the STL file format you can look on the
internet for it, there are plenty of resources for that. If you can't find
any then i'll give you a link.

Martin.
-------------------------------------------------------------
Hi, I'm a new learner. Now I want to display a STL model using ACIS, but I
really doesn't know how to do it. Anyone could give me some suggestions?
Thanks for your help!
-- 
shrimp
-------------------------------------------------------------


This message has been scanned but we cannot guarantee that it and any
attachments are free from viruses or other damaging content: you are advised
to perform your own checks.  Email communications with the University of
Nottingham may be monitored as permitted by UK legislation.