2004-april.txt

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From kkarkele at hotmail.com  Fri Apr  9 14:31:18 2004
From: kkarkele at hotmail.com (kapil karkele)
Date: Fri Apr  9 14:31:51 2004
Subject: [Acis-alliance] Creating new Solid from selected surfaces
Message-ID: <[e-mail]>

Hi,
Thanks for the mail. :) My purpose is to create a new solid from some 
surfaces of another solid.

I could create new solid by using api_unhook_face then creating new body out 
of the unhooked face and then using api_unite.

But then also if I am unhooking faces from open body then api_unite throws 
error message for some faces saying 'edge inconsistency' . Do anyone has 
idea about the same?

-regards,
kapil



>From: "Ames, Arlo" <[e-mail]>
>To: "'kapil karkele'" <[e-mail]>,[e-mail]
>Subject: RE: [Acis-alliance] Creating new Solid from selected surfaces
>Date: Thu, 8 Apr 2004 09:00:30 -0600
>
>You're asking a lot of these functions.  More than they're capable of (or
>even CAN be capable of).
>
>The semantically-ill-posed concern:
>
>So you decide to build a body out of some of the faces from a solid.  A
>subset of the faces of a solid cannot form a closed body.  And you can
>expect it to have sufficiently large gaps that the body cannot be closed;
>certainly not by healing, which expects to fix up small gaps in an 
>otherwise
>complete, closed topology.  I cannot see how you expect either the original
>"solid" or the new "solid" to close.
>
>There are special cases where you might get lucky in attempting to remove a
>set of faces from a solid -- an example is a "hole", which is bounded by a
>single loop in the middle of a face.  You can get lucky and be able to
>remove the faces of the hole from the solid without leaving irreparable
>holes in the result, as you're just removing a single loop from the 
>original
>solid.  In general, removal of faces from a solid is semantially ill-posed;
>you can create gaps in the solid for which no algorithm CAN exist to decide
>how to close them.  At best, an infinite number of solutions exist for
>closing the holes you create; at worst, you can create holes so large that
>infinite time can be expended attempting to find a closing set of geometry
>that makes sense.
>
>Your problem MUST be very carefully constrained, or you're attempting the
>impossible.  What are you trying to do (the big picture)?
>
>
>The topological "bug" that you can maybe try to patch over:
>
>When you extracted faces from the original solid, recall that they are
>stitched into that solid; they share coedges, so they continue to be
>adjacent to the faces in the original solid.  Api_mk_by_faces only expects
>to be stitching together a bunch of faces, and add appropriate shells,
>lumps, etc.  Since the faces were already stitched together, 
>api_mk_by_faces
>has no work to do at the coedge level, so does the trivial work above the
>faces and declares success, links the faces together in a list, and 
>declares
>success.  Again, they're still stitched to the faces in the other solid.
>
>During FACE collection, you should stitch each face out of the original
>solid.  Maybe api_remove_face does this, but I'd be VERY careful about the
>condition it leaves the "removed" face in.  Can't promise it doesn't leave
>it corrupt or deleted without checking the documentation (and the behavior
>-- I don't trust the documentation).  If it were me, I'd splice each face
>out of the original solid's list of faces -- make sure the previous face
>points to the removed-face's next face, and that the removed-face doesn't
>point to a next face.
>
>After collecting the faces, you need to traverse their loops, "splitting"
>each coedge that is shared with a face that lives in the original solid.
>That is, the EDGEs that are shared by COEDGE pairs that live on separate
>solids must be copied so that the COEDGE pairs no longer share EDGEs.  Same
>for VERTEXs shared between the old and new solid.  I don't know of an api
>function that does this; I'd do it myself.  Also, make sure that the 
>COEDGEs
>that were shared across the new solids no longer have partners, and that
>every EDGE and VERTEX along the shared boundary points upwards to an
>appropriate parent -- the original edge referred to one of the COEDGEs as
>its parent, and which one it chose was aribtrary in the original complete
>solid.
>
>After these concerns, api_mk_by_faces should be able to construct a partial
>solid from the list of faces you supply, and they won't be connected to the
>original solids' faces.  And the original partial solid should be
>topologically consistent.
>
>
>Again, I worry greatly about what you're trying to do (my first concern
>above).  I've given you here enough rope to hang yourself with.  This is an
>area where I personally tread very carefully.
>
>Arlo Ames
>[e-mail]
>
>-----Original Message-----
>From: kapil karkele [mailto:[e-mail]]
>Sent: Wednesday, April 07, 2004 8:58 PM
>To: [e-mail]
>Subject: [Acis-alliance] Creating new Solid from selected surfaces
>
>
>Hi,
>I am using Acis R10. In my code I have array of surfaces from Acis Body A
>from which I am creating new body B by calling api api_mk_by_faces and I
>have delete these surfaces from the original solid .
>The api api_mk_by_faces works fine.
>1)But when I am deleting those surfaces from the orignal solid after that 
>by
>
>calling api_remove_face then I get a error message saying 'Access
>Violation'.
>2)If I delete it before api_mk_by_faces then api_mk_by_faces fails saying
>'Access Violation'.
>3)I tried api_subtract after api_mk_by_faces  but I get error messge as
>'system inconsistency processing edge coincidence'.
>4)I tried healing the new body. As,
>api_initialize_healing();
>result = api_hh_init_body_for_healing(Newbody);
>result = api_hh_auto_heal(Newbody);
>CheckOutcome(result);
>api_terminate_healing();
>Then I got error message as ' Bodies with inconsistencies cannot be 
>healed'.
>5) I checked new Body by calling api_check_entity. And this also gives me
>the same error message as above.
>
>Is anywhere I am wrong to creae a new body from set of some surfaces from
>the orignal body?. Also which is the correct way to remove those surfaces
>after that?
>Anykind of reply is appreciating.!
>
>-Thanks and regards,
>kapil
>
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From zz_zxc123 at cims.sjtu.edu.cn  Mon Apr 12 04:34:21 2004
From: zz_zxc123 at cims.sjtu.edu.cn (zhang xuechang)
Date: Mon Apr 12 04:31:17 2004
Subject: [Acis-alliance] Please look at an API function api_point_in_face()
Message-ID: <001a01c42068$f3bc0650$c300a8c0@zxc>

Hello! everyone:
  I want to decide a point inside a face or outside a face.My code as follow. To make my doubt,the result is always point_inside_face. I don't know what wrong with it? Please help me!! Thanks!!

  
point_face_containment answer;
 if(is_spline_face(face))
   {
    for(int i=0;i<10;i++)
    {
    in_point.set_x(m_pData[i].x);
    in_point.set_y(m_pData[i].y);
    in_point.set_z(m_pData[i].z);
   
    SPAtransf const *tranform = get_owner_transf_ptr(face);
    API_BEGIN
    api_point_in_face(in_point,(FACE*)face,*tranform,answer);
    API_END
    if(answer==point_inside_face){
     api_find_cls_ptto_face(in_point,(FACE*)face,closepp);}
    }}


zhang xuechang
2004.4.12
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From iamsweeting at 163.com  Tue Apr 13 10:40:05 2004
From: iamsweeting at 163.com (iamsweeting)
Date: Tue Apr 13 10:37:12 2004
Subject: [Acis-alliance] How to show  api_boolean() result correctly?
Message-ID: <[e-mail]>

HI,
      //The following code programing in MFC, 

           BODY * A,B;
	m_pAcisView->m_pView->get_rendering_context()->add(A);
    api_boolean(B,A,SUBTRACTION);

//	       but why the result can not be show correctly?
//   if I remove the  A  from context befor bool operation and then add A to the context
//  ofter bool operation, It can show the result but it flashing; 
// Is there another way to show the result?
thans! 

　　
 				

　　　　　　　　yours sweeting
　　　　　　　　[e-mail]
　　　　　　　　　　2004-04-13




From NFarnsworth at web.de  Tue Apr 13 12:39:22 2004
From: NFarnsworth at web.de ([e-mail])
Date: Tue Apr 13 12:40:59 2004
Subject: [Acis-alliance] ACIS Law component
Message-ID: <[e-mail]>

Hello,
is there a posibilty to solve with the  ACIS Law component a linear system of equations.
For example (A-y*I)x=0. A is a Matrix, y is a double value, I is the identity Matrix and x is a Vector I search for.
Thanks for your support.
Niklas
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From zz_zxc123 at cims.sjtu.edu.cn  Thu Apr 15 08:24:43 2004
From: zz_zxc123 at cims.sjtu.edu.cn (zhang xuechang)
Date: Thu Apr 15 08:21:42 2004
Subject: [Acis-alliance] about hoops
Message-ID: <001001c422e4$a48df0b0$c300a8c0@zxc>

Hello!
I use hoops800 to handle a point cloud incudeling 150000 points. Now I want to delete some noisey points,or some points in an area. I use HOpSelectArea to do it,but the efficiency is very low. By the way my pointcloud is displayed in following code: 
HC_Open_Segment("view1");
for(int i=0;i{
HC_Set_Color_By_Value("markers","RGB",0,0,1);
HC_Insert_Marker(GetDocument()->m_pData [i].x,GetDocument()->m_pData[i].y,GetDocument()->m_pData[i].z);
}
HC_Close_Segment(); 

How to select pointcloud quickly and efficiently? 

Any help is my appreciation

zhang xuechang
2004.4.15

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From luo at irs.fzk.de  Tue Apr 20 02:34:50 2004
From: luo at irs.fzk.de (Luo, Yue-Tong)
Date: Tue Apr 20 02:36:51 2004
Subject: [Acis-alliance] About creating  quadric surface
Message-ID: <[e-mail]>

Hi,
Now I know implicit function of a quadric surface, anyone know how to
construct such surface in ACIS?
 
 
Any suggestion is welcome!
 
 
Best wishes,
Yuetong Luo
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From luo at irs.fzk.de  Tue Apr 20 09:46:01 2004
From: luo at irs.fzk.de (Luo, Yue-Tong)
Date: Tue Apr 20 09:47:36 2004
Subject: [Acis-alliance] About quadratic surface
Message-ID: <[e-mail]>

Hi, All,
Now I have some trouble with quadratic surface.  The problem is:
I know implicit equation of a quadratic surface, the form of equation is
Ax2 +By2+Cz2+2Dxy+2Eyz+2Fxz+2Gx+2Hy+2Gz+K=0; Now I can know quadratic
surface is a cylinder or a cone by ten coefficients (A, B, C,...K), but
I am not able to get parameter of the surface, for example, the radius,
axis of cylinder, etc. Can anyone provide some papers on this problem?
Any suggestion is welcome!
 
 
Best wishes,
Yuetong Luo
 
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From Nilesh.Joshi at asu.edu  Tue Apr 27 19:35:07 2004
From: Nilesh.Joshi at asu.edu (Nilesh Joshi)
Date: Tue Apr 27 19:41:29 2004
Subject: [Acis-alliance] Surface fitting
In-Reply-To: <[e-mail]>
Message-ID: <[e-mail]>

Hi guys,
I needed to know very urgently if ACIS provides any utility for fitting
surface to a given point cloud.
I need to fit given type of surface to given point cloud.
Please respond.

With Regards
-Nilesh Joshi
Design Automation Laboratory
Arizona State University

From alames at sandia.gov  Tue Apr 27 19:50:34 2004
From: alames at sandia.gov (Ames, Arlo)
Date: Tue Apr 27 19:54:59 2004
Subject: [Acis-alliance] RE: Surface fitting
Message-ID: <[e-mail]>

I am unaware of any pre-existing capability in ACIS, and I looked.  Hard.
Spatial at one time marketed something called the Revenge Husk, but
retracted the product.  It didn't do much.

I have written such a capability for fitting and classifying quadric
surfaces, but it would have to be licensed from Sandia.  Didn't get to do
NURBS surfaces, as funding ran out.  I have never pursued licensing of our
technology to a university, so can't guarantee the results.

What professors do you work with?  I have had a very good relationship with
Mark Henderson over the years.

Arlo Ames
[e-mail]


-----Original Message-----
From: Nilesh Joshi [mailto:[e-mail]] 
Sent: Tuesday, April 27, 2004 5:35 PM
To: [e-mail]
Cc: Ames, Arlo
Subject: Surface fitting


Hi guys,
I needed to know very urgently if ACIS provides any utility for fitting
surface to a given point cloud. I need to fit given type of surface to given
point cloud. Please respond.

With Regards
-Nilesh Joshi
Design Automation Laboratory
Arizona State University