2004-august.txt

acis说明文档

i have a body ,i want to get its outline that project onto a plane,
but i have no idea,can you help me?

thank you for your any advice you can provide!


From alames at sandia.gov  Tue Aug 17 12:21:44 2004
From: alames at sandia.gov (Ames, Arlo)
Date: Tue Aug 17 12:22:41 2004
Subject: [Acis-alliance] how to project a "body" onto a "plane" and
	ge t a "face"
Message-ID: <[e-mail]>

I may be wrong, but I don't know offhand of an API function that does this
directly.

2 approaches:

1.  If you don't need it to be too exact, and can live with facetization and
pixelization, think about GL (or other suitable hardware rendering
protocol).  Facet the part (to an appropriate accuracy), set up an
appropriate viewing transform, draw the pixels to an appropriate bitplane
with appropriate ALU mode, extract the bitmap.  If the bitmap starts off
black and you draw everything white, you can end up with a map, all the
regions where white touches black are edges of your outline.  You have to do
edge detection and construct a polygon map of the result.  It's actually
quite fast, and not too inaccurate, but requires good knowledge of GL.

2.  If it needs accuracy, looking at the Precise Hidden Line husk.  Think of
this as a visualization problem -- construct a parallel viewing projection,
draw the object, sort out the results.  The PHL will return a collection of
edges that, if drawn, represent those edges you'd see from some viewing
point.  Note that they'll be in 3D, and that you'll get all the edges as
seen from the viewing origin -- silhouette edges (edges that represent
interior of a face that goes tangent to the viewing direction) and portions
of part edges that are visible from the viewing position.  I don't recall
whether you get edges or coedges, and note that you might have coincident
edges.  You'd have to project onto a plane (you can sample the curves
yourself or you might find an appropriate api), noting that the projection
can cause edges to become coincident, bifurcating, etc) and imprint all the
endpoints of the projected edges onto all the other edges, then construct a
bounding polygon.  Make sure each start/end vertex of each edge knows all
neighboring edges.  Pick the edge with smallest X coordinate (it's sure to
be on the boundary), determine which direction to traverse it to be walking
CCW, examine list of edges at end vertex and find out which makes strongest
right hand turn.  Concatenate the edge with the first, and walk forward
until you get back where you started.

Arlo Ames
[e-mail]



-----Original Message-----
From: [e-mail]
[mailto:[e-mail]] On Behalf Of ??????
Sent: Tuesday, August 17, 2004 12:30 AM
To: [e-mail]
Subject: [Acis-alliance] how to project a "body" onto a "plane" and get a
"face"





i have a body ,i want to get its outline that project onto a plane, but i
have no idea,can you help me?

thank you for your any advice you can provide!


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


From asvaze at mtu.edu  Tue Aug 17 13:50:50 2004
From: asvaze at mtu.edu (Ajit Vaze)
Date: Tue Aug 17 13:51:06 2004
Subject: [Acis-alliance] Accessing face normal
Message-ID: <[e-mail]>

Hi all,

I need to access the normal vector of a planar face. I want to do it using
API functions. I have accessed a face using body->shell->face...
hierarchy.
I am not able to get to the face normal

Any help on this is appreciated.

Thanks,

Ajit

************************************************
Ajit Vaze
Graduate Student
Mechanical Engineering - Engineering Mechanics Department
Michigan Technological University
From alames at sandia.gov  Tue Aug 17 14:32:42 2004
From: alames at sandia.gov (Ames, Arlo)
Date: Tue Aug 17 14:33:24 2004
Subject: [Acis-alliance] Accessing face normal
Message-ID: <[e-mail]>

Face->surface will get you a SURFACE (there are variants depending on
whether you want a copy or whatever).  Cast (dynamically, type unsafe,
whatever) the SURFACE to a PLANE.  Ask the PLANE for its plane.  Ask the
plane for its point and normal.

Alternatively, there are SURFACE query functions for normal at a point that
you could use, even if the surface isn't a plane.

Arlo Ames
[e-mail]

-----Original Message-----
From: [e-mail]
[mailto:[e-mail]] On Behalf Of Ajit Vaze
Sent: Tuesday, August 17, 2004 11:51 AM
To: [e-mail]
Subject: [Acis-alliance] Accessing face normal


Hi all,

I need to access the normal vector of a planar face. I want to do it using
API functions. I have accessed a face using body->shell->face... hierarchy.
I am not able to get to the face normal

Any help on this is appreciated.

Thanks,

Ajit

************************************************
Ajit Vaze
Graduate Student
Mechanical Engineering - Engineering Mechanics Department Michigan
Technological University _______________________________________________
Acis-alliance mailing list
[e-mail]
http://lists.cs.columbia.edu/mailman/listinfo/acis-alliance

From asvaze at mtu.edu  Tue Aug 17 16:24:46 2004
From: asvaze at mtu.edu (Ajit Vaze)
Date: Tue Aug 17 17:06:16 2004
Subject: [Acis-alliance] Accessing face normal
In-Reply-To: <[e-mail]>
References: <[e-mail]>
Message-ID: <[e-mail]>

Hi Arlo,

It worked!! I got normal vector by casting SURFACE as PLANE.

Thanks a lot for your prompt reply

Ajit.



From xlr_yzy at 163.com  Wed Aug 18 07:22:53 2004
From: xlr_yzy at 163.com (=?gb2312?B?eGxyX3l6eQ==?=)
Date: Wed Aug 18 07:23:21 2004
Subject: [Acis-alliance] how to get a cuboid!
Message-ID: <[e-mail]>


hello!
I'm new to ACIS. I am having some trouble trying to get a "hello world" program running. 
All i want to do is create a cuboid and save it to a .dbg file. However, whenever i try to save to a file using the "debug_size" function, i get an error:
"  error C2664: 'debug_size' : cannot convert parameter 1 from 'class BODY *' to 'const class ENTITY *' "
here's the code:
#include <stdio.h>
#include "api.hxx"
#include "kernapi.hxx"
#include "cstrapi.hxx"
#include "debug.hxx"
#include "entity.hxx"
#include "acis.hxx"

void main()
{
	api_start_modeller(0);
	api_initialize_constructors();
	BODY  *block;
	api_make_cuboid(100,50,200, block);
	FILE *output=fopen("cube.dbg","w");
	debug_size(block,output);//error C2664: 'debug_size' : cannot convert parameter 1 from 'class BODY *' to 'const class ENTITY *'
	fclose(output);
	api_terminate_constructors();
	api_stop_modeller();
}

i'm appreciated for your help!
                                                  xuliru

-------------------------------------------------------------------------------------嘉年华挑战快乐极限,你敢玩吗? http://smspop.163.com/personal/wang/17/index.htm
From lzguo at jlu.edu.cn  Sat Aug 21 08:20:39 2004
From: lzguo at jlu.edu.cn (Liu zhiguo)
Date: Sat Aug 21 08:21:19 2004
Subject: [Acis-alliance] Question of api_split_curve
Message-ID: <[e-mail]>

Dear all,

  I use api_split_curve to split a EDGE by another EDGE. First, I create a plane, then create a line. I want to split the EDGE by the line, if they are intersected. At last, I want to get the splited EDGEs. But I check the result file, there are only one edge in the newlist. The newlist is the list of splited curves. I don't know why the curve did not been splited. Wo can tell me how to use this function and get two splited curves? Any help will be greatly appreciated. 

	Init_Geometry();
	ENTITY_LIST testlist;
	EDGE *line1, * line2;
	FACE * plane1;
	SPAvector vec2(0,0,1);
	api_face_plane(SPAposition(0,0,0),100,50,&vec2,plane1,NULL);
	api_curve_line(SPAposition(-10,10,0), SPAposition(40,10,0), line1);
	ENTITY_LIST edgelist1;
	ENTITY_LIST newlist;
	get_edges_main(edgelist1,plane1);
	printf("number of edge is : d\n",edgelist1.count());
	logical touch1;
	for(i=0;i<edgelist1.count();i++)
	{
		touch1=FALSE;
		EDGE *temedge=(EDGE *)edgelist1[i];
		api_entity_entity_touch(temedge,line1,touch1, NULL);
		if(touch1)
		{
			api_split_curve(temedge,NULL,line1,newlist,NULL);
			goto jump; 
		}

	}
jump:	printf("number of new edge: d\n",newlist.count());
	for(i=0;i<newlist.count();i++)
	{
		EDGE * eee=(EDGE *)newlist[i];
		eee->set_coedge(NULL);
		testlist.add(eee);
	}


Zhiguo liu
2004-8-21


From pro_thinker at yahoo.com  Thu Aug 26 18:40:21 2004
From: pro_thinker at yahoo.com (Venkat)
Date: Thu Aug 26 18:38:43 2004
Subject: [Acis-alliance] acis integration with java
Message-ID: <[e-mail]>

Hi,

Can anyone plz provide details on how ACIS can be integrated with an
application written in java using JNI? If you can direct me to some source,
that would be great.

Thanks,

Venkat

 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.cs.columbia.edu/pipermail/acis-alliance/attachments/20040826/67b03451/attachment.html
From muthler at bv.tum.de  Thu Aug 26 18:55:43 2004
From: muthler at bv.tum.de (Alexander Muthler)
Date: Thu Aug 26 18:48:30 2004
Subject: [Acis-alliance] acis integration with java
In-Reply-To: <[e-mail]>
Message-ID: <[e-mail]>

Hi,
 
I have heard that the institute for computer science in civil engineering at
Uni Weimar in Germany made a java-integration. Maybe you can find some
information on their hompage.
 
Regards,
Alex


  _____  

From: [e-mail]
[mailto:[e-mail]] On Behalf Of Venkat
Sent: Friday, August 27, 2004 12:40 AM
To: [e-mail]
Subject: [Acis-alliance] acis integration with java



Hi,

Can anyone plz provide details on how ACIS can be integrated with an
application written in java using JNI? If you can direct me to some source,
that would be great.

Thanks,

Venkat

 

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.cs.columbia.edu/pipermail/acis-alliance/attachments/20040827/0250fc93/attachment.html
From guillaume.poirier at righthemisphere.com  Fri Aug 27 00:14:46 2004
From: guillaume.poirier at righthemisphere.com (Guillaume Poirier)
Date: Fri Aug 27 00:15:11 2004
Subject: [Acis-alliance] Trimmed NURB surfaces from faces
Message-ID: <[e-mail]>

Hi All,
 
 
I am trying to get trimmed NURBs data from faces... I am doing something
similar to one previous post I've seen on the subject, however it seems
I have a problem with the UV curves knots returned being incorrect. I am
doing something like to read the trimming curves:
 
api_initialize_spline(); 
bs3_curve_init();
 
// loop through face / loop / coedges / edges
 
EDGE *edge_ptr = coedge_ptr->edge();
CURVE *curve_ptr = edge_ptr->geometry()
const curve* crv = &(curve_ptr->equation());
 
SPAinterval inter = crv->param_range();
bs3_curve b3crv = bs3_curve_make_cur(*crv, inter.start_pt(),
inter.end_pt());
 
int dim, deg, num_ctrlpts, num_knots;
logical rat;
SPAposition *ctrlpts = NULL;
double *weights = NULL;
double *knots = NULL;
   
bs3_curve_to_array(b3crv, dim, deg, rat, num_ctrlpts, ctrlpts, weights,
num_knots, knots);
 
Interestingly, all curves of type intcurve_type are correct, i.e. have
proper cpts, knots, etc. Curves of types straight_type and ellipse_type
however return incorrect knots values (correct number of knots though).
The control points and weights are also correct for those two types. 
 
Moreover, I was wondering if it is possible to get parameter space
trimming curves instead of 3D curves... Anyone knows how to do that ?
How does trimming loops work in Acis ? Is there an outer loop and some
inner loops like in some other solid modeling kernels ? How can we know
if a loop defines a hole or solid ?
 
I am sorry if these are simple questions but I just started using the
Acis kernel today... I though the documentation would discuss something
as basic as trimmed NURB surfaces but I did not find the information I
was looking for :(
 
 
Best regards,
 
 
Guillaume
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.cs.columbia.edu/pipermail/acis-alliance/attachments/20040827/7898dc43/attachment.html