Point Cloud Analysis

[cdoyle_arcdox_com]

Having issues with my Point Cloud analysis function, i have linked a point cloud into my project - its an .rcs i cant seem to get a deviation result, only 'All points fell outside the max deviation' is there a particular workflow i need to follow...any help?

[s.hamel]

I am going to guess that you are dealing with a very large coordinate system, please verify if this is the case or not. If so, you are probably running into a known issue in Revit dealing with this scenario, in which case the only current solution would be to create a version of the point cloud with a coordinate system matching the relative coordinate system of revit and insert that.

Thanks,
Shayne Hamel

[fionn]

Revit model (2016) with Point layout and a scan loaded

Model is in shared coordinates base point:

183600000
544500000

Click on Cloud analysis

Allow for a distance of 200mm – although this is way over tolerance (20mm for concrete)

Select some surfaces

Press Finish

Message: 'All points fell outside maximum deviation'

Any help would be great.

Fionn

[s.hamel]

Hello Fion, this issue appears to be the same as the original posting.  You have a large coordinate system, and there was a known issue with the point cloud API in Revit 2015/2016 when dealing with very large coordinate systems.  The issue is resolved in Revit 2017, so if that is an option for you it would be easiest to run these functions within Revit 2017.  However if this is not an option, the other thing you could do is use Update Origin command in ReCap to change the origin of the scans, then export the updated data to a new rcs which Revit can work with (Make a new shared coordinate system in Revit matching the origin adjustment you make to the scan/s).

Let me know if you have followup question/s.

Thanks,

Shayne

[fionn]

Shayne,

Thanks for the quick response. I will try the Revit 2017 trial but we do not have this yet in terms of company roll out so ideally I would be able to persist with 2016. Would you be able to assist further by providing an example of how you would reposition the origin of the Recap file and then match this back to a Revit file? This work flow worries me slightly because I was adamant with the surveyor that he needed to position the scan in world coordinates..so the last thing I want is end up with something that no longer reflects the 'true position' for comparison due to my own lack of knowledge on how to manipulate the origins of both files. If there is anything online that describes your workaround that would be great - I cannot find anything myself. Thanks for your help.

Fionn

[s.hamel]

Fionn, unfortunately I am far from knowledgeable on the Recap side. I know you can set origin in there by specifying the coordinates for a specific point, so if you can add in a point that is sitting at your base point mentioned:
Model is in shared coordinates base point:
183600000
544500000

Then you could specify it as 0,0,0 and export the scan back out.

On the Revit side, easiest thing to to is duplicate your current Shared coordinate system, set it to current, then in the view make sure you have your Survey point shown in Visibility graphics, and you can modifying it on screen to be 0,0,0.

Import that adjusted point cloud based on this new shared coordinate system and you should be good to go. Probably the hardest part...finding the point to set the origin to in the point cloud.

Thanks,
Shayne

[fionn]

Hi Shayne,

I managed to get something working in Revit 2017..but I am quite sure that the result is incorrect. Do you know if there have been any tests done by Autodesk to validate these results and if the large coordinate system could be a contributing factor? (is there anyway to check the results apart from manually dimension from point cloud to model surface). Would you be interested in seeing the files in question?

Thanks,

Fionn

[s.hamel]

The large coordinate system could certainly be a contributing factor, it was in the prior releases, one result of course being the issue you saw with this not working.  Definitely interested in checking out what you are seeing, PM me links and I'll take a look.

Thanks,

Shayne

[JoshMason]

I'm having the same issue as above. I've checked all my coordinate systems and their all located in the center of my model around the scan. 

When I run the cloud analysis, I get a highlight of all the points that are within the maximum deviation set in blue - however they don't show any of the analysis. 

I'm comparing a point scan to structural columns. Not sure if any of that's relevant. 

[JoshMason]

should have attached screen capture

[s.hamel]

When you have nothing selected, properties pane will show for your current 3D view.  Under the Graphics section find Analysis Display Settings, hit the Edit option, and make sure you have the "Show analysis results in this view" checked.  You should also see in the list the APL style and have a check under its visible column.  If that's not the issue, you can PM me a link for the drawing and I will take a look.

Thanks,

[biuro]

I have attached the point cloud into the project (screen 3). When I run the cloud analysis, few of the walls and columns were analized, but not all of them (screen 1 and 2). The point cloud around the columns, which were not analized, is highlighted and any results of the analysis are not visible, and there is a report that 'All points fell outside the max deviation' (screen 1). 

[s.hamel]

Hello Biuro, if you increase the maximum deviation does it then include those surfaces?  Unfortunately there is no way to really provide more insight without being able to reproduce the issue.  If you want to message me links to download, I can take a look when time permits.

Thanks,