Re: Constructing pfASD

New Message Reply Date view Thread view Subject view Author view

Thom DeCarlo (trdecarlo++at++tasc.com)
Wed, 15 Apr 1998 10:24:59 -0400

Lee Willis wrote:

> From: Dan Brockway <db++at++ParadigmSim.com>
>
>> Lee Willis wrote:
>>
>> > So far I don't understand what the problem is. The Multigen CAT
>> > implementation of ASD does just that, picks out the most significant
>> > points for each LOD, working from coarsest to finest, injecting new
>> > points to each LOD to better approximate the surface.
>>
>> If, on the other hand, you have a specific terrain surface at the highest
>> LOD that correlates with other databases, then MultiGen's CAT is of no
>> value.
>
> No argument. But the problem goes deeper than that. If you have a specific
> terrain surface at the highest LOD that correlates with other databases,
> ***ASD*** is of no value. (unless you're database happens to be a regular
> grid)
>
> You cannot construct an ASD from an arbitrary triangular mesh. It just aint
> doable.
>

I'm sure you will correct me if I am wrong, but since we are talking about
starting from the raw source (DTED type data), we do have a regular grid. The
triangular mesh needn't be generated until much later in the process. It seems
to me that there should be a straight-forward, though time-consuming, process
that looks at each point in the highest resolution set, finds the nearest
point in the next lower resolution set, and identifies that as the "morph to"
point.Since you say this is hard, there must be something I am missing.

> ------------------------------
> Lee Willis Virtual Landscape Dermatologist
>
> lwillis++at++terrex.com TERREX

  ------------------------------------------------------------------------
          Thom DeCarlo Off site contact info
          TASC JPSD/IEC, US Army TEC
          12100 Sunset Hills Rd. 7701 Telegraph Rd., Bldg.
                                       2592
          Reston, VA 20190 Alexandria, VA 22315
          phone: 703/834-5000 phone: 703/428-9001, -7060,
                                       or -7034
          fax: 703/318-7900 fax: 703/428-7054
          mailto:trdecarlo++at++tasc.com mailto:tdecarlo++at++rayva.org
  ------------------------------------------------------------------------
           The goal of program development is to make sure there is
                  at least one right way to use the software.
           The goal of product development is to make sure there is
                       no wrong way to use the software.

Lee Willis wrote:

From: Dan Brockway <db++at++ParadigmSim.com>
Lee Willis wrote:
So far I don't understand what the problem is.   The Multigen CAT implementation of ASD does just that, picks out the most significant points for each LOD, working from coarsest to finest, injecting new points to each LOD to better approximate the surface.
If, on the other hand, you have a specific terrain surface at the highest LOD that correlates with other databases, then MultiGen's CAT is of no value.
No argument. But the problem goes deeper than that. If you have a specific terrain surface at the highest LOD that correlates with other databases, ***ASD*** is of no value. (unless you're database happens to be a regular grid)

You cannot construct an ASD from an arbitrary triangular mesh. It just aint doable.
 

I'm sure you will correct me if I am wrong, but since we are talking about starting from the raw source (DTED type data), we do have a regular grid. The triangular mesh needn't be generated until much later in the process. It seems to me that there should be a straight-forward, though time-consuming, process that looks at each point in the highest resolution set, finds the nearest point in the next lower resolution set, and identifies that as the "morph to" point.Since you say this is hard, there must be something I am missing.

------------------------------
Lee Willis                        Virtual Landscape Dermatologist

lwillis++at++terrex.com           TERREX

 
Thom DeCarlo Off site contact info
TASC JPSD/IEC, US Army TEC
12100 Sunset Hills Rd. 7701 Telegraph Rd., Bldg. 2592
Reston, VA 20190 Alexandria, VA 22315
phone: 703/834-5000 phone: 703/428-9001, -7060, or -7034
fax:   703/318-7900 fax:   703/428-7054
mailto:trdecarlo++at++tasc.com mailto:tdecarlo++at++rayva.org
The goal of program development is to make sure there is
at least one right way to use the software.
The goal of product development is to make sure there is
no wrong way to use the software.

======================================================================= List Archives, FAQ, FTP: http://www.sgi.com/Technology/Performer/ Submissions: info-performer++at++sgi.com Admin. requests: info-performer-request++at++sgi.com

New Message Reply Date view Thread view Subject view Author view

This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:57:14 PDT

This message has been cleansed for anti-spam protection. Replace '++at++' in any mail addresses with the '@' symbol.