2004-april.txt

acis说明文档

>> >- create as few triangles as possible
>> >- create all non-triangles as poygons with 4 vertices (Positions)
>> >- limit number of quads and triangles (e.g. 250+-50, 100+-50)
>> >
>> >
>> >Is there any possibility to get this options by configuring the
>> >Refinement?
>> >
>> >Thank you very much for your support
>> >
>> >
>> >
>> >Juergen Wehr
>> >_______________________________________________
>> >Acis-alliance mailing list
>> >[e-mail]
>> >http://lists.cs.columbia.edu/mailman/listinfo/acis-alliance
>>
>>
>>
>> _______________________________________________
>> Acis-alliance mailing list
>> [e-mail]
>> http://lists.cs.columbia.edu/mailman/listinfo/acis-alliance



From kkarkele at hotmail.com  Mon Apr  5 23:49:41 2004
From: kkarkele at hotmail.com (kapil karkele)
Date: Tue Apr  6 10:31:59 2004
Subject: [Acis-alliance] Highlighting entities
Message-ID: <[e-mail]>

Dear acis-alliance,
I am not able to Highlight the acis faces using the following code.

int n_faces = face_list.count();
for (int iSurf = 1, k = 0; iSurf < iTotal; iSurf++, k++)
{
     outcome rc = api_gi_highlight_entity(face_list[k],TRUE);
}

where face_list is ENTITY_LIST . I am using acis R10. I will be grateful if 
anyone can help me to sort out the problem. Actually I am using OpenGl for 
display purpose. Can this affect the behaviour of acis api?

-Thanks and regards,
kapil

_________________________________________________________________
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From alames at sandia.gov  Tue Apr  6 11:07:38 2004
From: alames at sandia.gov (Ames, Arlo)
Date: Tue Apr  6 11:09:09 2004
Subject: [Acis-alliance] About Boolean Operation
Message-ID: <[e-mail]>

What do you mean by incorrect?  The resulting body has, say no lumps, etc?
Or the result is completely fallacious (you expected 30 faces and got 2)?  
 
What version of ACIS are you running?  Older versions had MANY more problems
than current versions.
 
Boolean operations are not completely robust in any current modeling system.
You have to be careful of what you feed it in order to get good results.
Have you run api_check on the objects going in to the boolean?  Are they
closed, accurate, well-formed?
 
If everything else fails, contact Spatial.  This is really their problem.
 
Arlo Ames
[e-mail]
-----Original Message-----
From: Luo, Yue-Tong [mailto:[e-mail]] 
Sent: Friday, April 02, 2004 12:30 AM
To: [e-mail]
Subject: [Acis-alliance] About Boolean Operation


Hi,
   I call res = DoBoolean(b1, b2) in my program to implement Boolean
operation between b1 and b2.  Res.ok() is true, but the result returned by
b2 is incorrect, What is the matter? And how can I detect such error?
 
Thank you in advance!
Yuetong Luo
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From T.Mwinuka at postgrad.umist.ac.uk  Tue Apr  6 12:40:32 2004
From: T.Mwinuka at postgrad.umist.ac.uk (Tito Mwinuka)
Date: Tue Apr  6 12:41:36 2004
Subject: [Acis-alliance] Re:Highlighting entities
In-Reply-To: <[e-mail]>
References: <[e-mail]>
Message-ID: <[e-mail]>

I had a similar problem sometimes in the past. Since the faces were accessed 
by going from (BODY*)body->lump()->shell()->face(); then next_in_list() to 
proceed to other faces, the highlighting started to work when I inserted a line
    
 api_gi_highlight_entity(body,FALSE)

well before I reached the faces. I have absolutely no idea as to why it worked.
where 'body' is the entity I restored from file.
I will paste my piece of code here if it can be of any help



	FILE* pfile=fopen("c:/directory/adapter.sat","r");
	ENTITY_LIST elist;
	outcome result=api_restore_entity_list(pfile,TRUE, elist);
	
	m_pAcisDoc->InvalidateViews();
        for (int i=0; i<elist.count(); i++)
	{
		ENTITY* ent=elist[i];
		m_pAcisDoc->AddEntity(ent);
           //if i remove the following line, highlighting doesn't work
	    api_gi_highlight_entity(ent,false);
    	    BODY* ent1=(BODY*)ent; 
            LUMP* lump1=ent1->lump(); 

    	    SHELL* shell1=lump1->shell();
	   
		
		FACE* face1=shell1->face();  int position=0;
		while (face1)
		{
		/*	if (position==6)*/ api_gi_highlight_entity(face1,true);
			face1=face1->next_in_list();
			position=position+1;
		
		}
	
	}

If I remove the commenting out above only the seventh face is highlighted
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 06 Apr 2004 03:49:41 +0000
> From: "kapil karkele" <[e-mail]>
> Subject: [Acis-alliance] Highlighting entities
> To: [e-mail]
> Message-ID: <[e-mail]>
> Content-Type: text/plain; format=flowed
> 
> Dear acis-alliance,
> I am not able to Highlight the acis faces using the following code.
> 
> int n_faces = face_list.count();
> for (int iSurf = 1, k = 0; iSurf < iTotal; iSurf++, k++)
> {
>      outcome rc = api_gi_highlight_entity(face_list[k],TRUE);
> }
> 
> where face_list is ENTITY_LIST . I am using acis R10. I will be grateful if
> 
> anyone can help me to sort out the problem. Actually I am using OpenGl for 
> display purpose. Can this affect the behaviour of acis api?
> 
> -Thanks and regards,
> kapil
> 
> _________________________________________________________________
> Easiest Money Transfer to India. Send Money To 6000 Indian Towns. 
> http://go.msnserver.com/IN/42198.asp Easiest Way To Send Money Home!
> 
> 
> 
> ------------------------------
From NFarnsworth at web.de  Wed Apr  7 14:08:41 2004
From: NFarnsworth at web.de ([e-mail])
Date: Wed Apr  7 14:10:12 2004
Subject: [Acis-alliance] problem with calculating mass properties
Message-ID: <[e-mail]>

Hello,
I have a probleme with calculation of mass properties of an ACIS Body. I do this with the c-api function api_body_mass_pr
which calculates inertial tensor and the principal moments. My question is, how can I get the rotation matrix of the
center of gravity system which is relative to the body system. I thougth that I can calculate the rotation matrix by solving the
equation Js=Vt*JV where Js is the principal moment matrix or diagonalized inertial tensor an J is the inertial tensor. V is the transformation matrix which is the rotation matrix I search for.
I can solve the equation by finding the eigenvector. My problem is that the result matrix V is not correct.
I thought that I have to take in account that  the inertial tensor is relative to the body but it have to relative to center of gravity system but this did not help.
Could somebody tell me what the mistake is? 
Thanks for your support 
Niklas

____________________________________________________________________
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From alames at sandia.gov  Wed Apr  7 15:29:42 2004
From: alames at sandia.gov (Ames, Arlo)
Date: Wed Apr  7 15:31:01 2004
Subject: [Acis-alliance] problem with calculating mass properties
Message-ID: <[e-mail]>

As I recall, the api function returns principal axes, a mutually orthogonal
set.  The function coordinate_transf will construct a transformation to take
origin, x, y, z coordinate system to new_orgin, new_x_axis, new_y_axis
system.  Just pass the CG, and 2 of the principal axes, to the function and
you'll get the transform.  Note that the solution you'll get is not unique
-- you can negate either the new_x or new_y axis and get another transform
that meets your criteria.

Arlo Ames
[e-mail]

-----Original Message-----
From: [e-mail] [mailto:[e-mail]] 
Sent: Wednesday, April 07, 2004 12:09 PM
To: [e-mail]
Subject: [Acis-alliance] problem with calculating mass properties


Hello,
I have a probleme with calculation of mass properties of an ACIS Body. I do
this with the c-api function api_body_mass_pr which calculates inertial
tensor and the principal moments. My question is, how can I get the rotation
matrix of the center of gravity system which is relative to the body system.
I thougth that I can calculate the rotation matrix by solving the equation
Js=Vt*JV where Js is the principal moment matrix or diagonalized inertial
tensor an J is the inertial tensor. V is the transformation matrix which is
the rotation matrix I search for. I can solve the equation by finding the
eigenvector. My problem is that the result matrix V is not correct. I
thought that I have to take in account that  the inertial tensor is relative
to the body but it have to relative to center of gravity system but this did
not help. Could somebody tell me what the mistake is? 
Thanks for your support 
Niklas

____________________________________________________________________
Der WEB.DE Virenschutz schuetzt Ihr Postfach vor dem Wurm Sober.A-F!
Kostenfrei fuer FreeMail Nutzer. http://f.web.de/?mc=021158

_______________________________________________
Acis-alliance mailing list
[e-mail]
http://lists.cs.columbia.edu/mailman/listinfo/acis-alliance

From zhengshu.shen at asu.edu  Wed Apr  7 19:05:54 2004
From: zhengshu.shen at asu.edu (shen)
Date: Wed Apr  7 19:01:46 2004
Subject: [Acis-alliance] how to obtain FACE parameter
References: <[e-mail]>
Message-ID: <[e-mail]>

Hello!
If I have a analytic surface (plane, cone, sphere, torus), in terms of a
FACE pointer, how can i get the corresponding parameters for it? For
instance, if I have a cylindrical FACE, how can I get its diameter and
height? Any API functions?
Thank a lot.

Shen

From kkarkele at hotmail.com  Wed Apr  7 22:58:02 2004
From: kkarkele at hotmail.com (kapil karkele)
Date: Wed Apr  7 22:59:04 2004
Subject: [Acis-alliance] Creating new Solid from selected surfaces
Message-ID: <[e-mail]>

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 kkarkele at hotmail.com  Thu Apr  8 00:49:07 2004
From: kkarkele at hotmail.com (kapil karkele)
Date: Thu Apr  8 00:50:06 2004
Subject: [Acis-alliance] Speed related Issues
Message-ID: <[e-mail]>

Hi,
I am using Acis R10. There are many api's which I think are slow.
1)api_entity_entity_distance : To find out shortest distance betn two 
entities I am using this api which is very slow in computation. Is there any 
alternative for this?
2) api_facet_entity :- Depending upon the normal tolerance (the angle 
between the surface normals at the two adjacent nodes of a facet) this api 
takes time. Increasing this value improves speed but faceting performance is 
hampered. Is there any other workaround to this? Actually in R11 there are 
different mesh managers like LINKED_MESH_MANAGER  which is used to speed up 
the faceting but I have to use R10 .
3)get_body_box : This is the api which takes time depending on body size.

Can I improve the speed in these kind of situations?
Thanks and regards,
kapil

_________________________________________________________________
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From alames at sandia.gov  Thu Apr  8 11:00:30 2004
From: alames at sandia.gov (Ames, Arlo)
Date: Thu Apr  8 11:02:20 2004
Subject: [Acis-alliance] Creating new Solid from selected surfaces
Message-ID: <[e-mail]>

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