Z+F point cloud misalignment with PDMS model

[Big_G]

Hello I am a little bit stuck and wonder if anyone has a useful suggestion :)

We have a PDMS model, and a laser survey all visable through the LMI in design... so far so good. :)

The probelm is that the PDMS model has been created at an arbitary datum to always give positive values. (modelled at 100000 E 100000 N 100000 U) The Laser survey however has been generated about a different datum and (unsurprisingly) it is 100000 away from where is should be :(

Need the survey and PDMS model to align as we have Brownfield modelling/clashing to do.

After considering various options for moving the PDMS model to the survey (1. physically moving the model- not good we have several draft drawings and other dependancies.... 2. Using extracts or copying the whole project to create a special "Laser survey" version of the project but this would not be dynamic to and is a bit of an abuse) the superior option must be to move the Survey to the model. But he question is how???!!

The cloud has been supplied by the client we have the normal LMI server running but there is no obvious way to move the survey. Moving the "special" LMI elements in Design does little but upset it. Anyone got any ideas ??

[codooaustin]

You have three options:

1.) Have the service provider who did the laser scanning regenerate the point cloud at your new coordinates. This could take a day or two and most likely wouldn't be free.

2.) You move your model to the coordinates used for the scanning.

3.) You create a special project like you mentioned.

[Big_G]

Many thanks for the prompt help Codoo :)

I agree with you.... had a feeling that this cloud would need to be repositioned "upstream" of PDMS and the LMI.

I think I will have find a a bit of a dirty solution through a bit of creative PDMS.

It's not pretty but it sure beats writing another cheque! :)

[Iaing]

It is possible to move the point cloud data from within the .LFD file.

Open the .LFD in a text editor

There should be two sets of co-oridnates (easting, northing, elevation) at the top of the file eg.

------------

5
98.62381525 306.33824700 35.66457661 1.0 0.0 0.0

X
98.62381525
306.33824700
35.66457661
129

-----------------------

The first set of co-ordinates tells the viewer where the opening point of the scan is.

The second set controls the position of the database.

Therefore to move the point cloud just increase or decrease the numbers based on its new position.

Be warned the database should be signed after modifying co-ordinates otherwise an error message will be displayed when loading the scan, however it will still work if you dont sign the database.

The database will need to be recompiled for any rotational change

Hope this helps

Iain

[Big_G]

Many thanks for this I will experiment and let you know how I get on. I don't know how to "sign" a database I assume this is some kind of closure to the file normally applied by an editing application?? I can live with an error message or two, but it would be nice to know... fortunately both PDMS and Cloud are orientated correctly for me. I think changing 3 co-ords falls safely within my skill set :)

[codooaustin]

You're playing with fire. In order to sign/re-sign the database you need LFM Generator which cost's about $10,000. Service providers use it to generate the point cloud.

[Big_G]

I had a feeling.... that I could smell something burning :) Thanks the detail again Codoo.

That's fine I have a safe copy of the cloud I will have a play and see how I get on... One error message a day sounds better than $10k

[Graham]

I would add to Cody's comments you are playing with fire. You may get unexpected results in that the graphics might appear in the correct place but the underlying points when clashed might not be correct. I have seen this with other partners software.

When we implemented the Laser Model Interface the consensus of opinion we recieved from the partners was best not move the laser data within AVEVA products. Get the survey in the right place to start with.