CGAL users discussion list

["naresh" <>]



 

Hi Peter

 

>> We use a kd-tree for point location and ray shooting. But I guess
>> that was not what you were asking for, was it?

 

You are right. Basically I read in Geometeric Tools by Eberly about BSP tree. Acording to him BSP tree will faster then linear intersection.

But you said it use Kd-tree so it will do same Job as BSP so speed will be same.  In fact i was trying to search why CGAL implemetation of nef_3 is slower.

 

BTW. Since you are the auther let me ask .

Is there any method i can increase speed because my application has lot of operations. ?

 

Alex

 

 

 

 

----- Original Message -----

From:

To:

Sent: Monday, May 11, 2009 3:51 PM

Subject: Re: [cgal-discuss] Nef_3 Question

We use a kd-tree for point location and ray shooting. But I guess
that was not what you were asking for, was it? Look into
the manual to get an idea of the data structure, or have
a look at the papers on our implementation for a deeper
insight.

http://www.win.tue.nl/~phachenb/Nef/Nef3D-DataStructureAlgorithms.pdf

Peter

-----"naresh" <> wrote: -----

To: <>
From: "naresh" <>
Date: 05/11/2009 10:52AM
Subject: Re: [cgal-discuss] Nef_3 Question

Hi

> Unfortunately, the algorithms from the Nef package can not work with
> inexact numbers. I think one would need to use a completely different
> approach to make booleans work with inexact math, but that would
> probably sacrifice correctness in certain cases.

Is the polyhydron intersection is implemented with BSP tree ?



----- Original Message -----
From: "Bart Janssens" <>
To: <>
Sent: Saturday, May 09, 2009 8:57 PM
Subject: Re: [cgal-discuss] Nef_3 Question


> On Sat, May 9, 2009 at 1:20 PM, naresh <> wrote:
>> I am trying to find two polyhydron intersection in nef_3 package. But i
>> found process is very slow because of exact arithmatic calculations.
>>
>> So i have question can i use use inexact arithmatic that gives me speed ?
>
> Hi Alex,
>
> Unfortunately, the algorithms from the Nef package can not work with
> inexact numbers. I think one would need to use a completely different
> approach to make booleans work with inexact math, but that would
> probably sacrifice correctness in certain cases.
>
> Cheers,
>
> --
> Bart
> --
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