Question about aligning point-clouds for Navisworks 2013

[christian.storay]

So I have this point-cloud of an existing building, and it's aligned in Revit with the Architectural, Structural, and MEP models.  There's no problem for us there because the tools in Revit are pretty good for this sort of thing.  However, we also want it aligned in Navisworks for our coordination meetings and the important people here who don't want to fool with Revit.

The goal for the project is to construct all the walls and utilities on an unfurnished floor of a fairly new building, and we're handling the coordination for that using this software.  We made a nice and very large point cloud using Faro hardware, and like I said before we had no trouble aligning it to our existing files in Revit.

What we want to do is export that pointcloud from Revit in it's existing, already-aligned location to Navisworks, so we don't have to move it or eyeball it in Navisworks.  If this were possible, it would just show up in the right location and we would be happy.

However, I can't seem to find out how to do this.  The point cloud is not carried over when I load the Revit file into Navisworks 2013.  It also doesn't work when I use the exporter.  Nor does it work when I export in any other format from Revit.  It appears that Revit is a dead end for point cloud information, and I'm hoping that there is a solution to this that doesn't involve attempting to align it with the existing-construction models within Navisworks.

[john.lipp]

Dear cstoray

Revit converts the point cloud file to a PCG file upon import.  Navisworks does not currently support PCG files nor export the linked Point Cloud file from Revit.

I recommend sending a wishlist item for this functionality through our feedback page linked below:

http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=1109794

Our development monitors the information that is sent through this page and is always interested in your feedback.

To move the point cloud into position after appending it in Navisworks you can:

1. Use File Units and Transform to align your point cloud

2. Select the point cloud file and use Item Tools > Transform to move it into position

3. Use the Point to Point measure tool  (View > Workspace > Windows > Measure Tools) and pick a point in the point cloud and another point in your other model that match the same point in space.  Then select the point cloud file and use the Transform Objects tool in Measure Tools which will move it that distance.


Best regards,



John Lipp
Support Specialist
Product Support
Autodesk, Inc.

[christian.storay]

I was hoping I wouldn't have to move it again, but thank you for your help. I have sent my wish-list item as you suggested.

[afinnerty]

Has this been resolved yet? This is a HUGE disconnect between Revit and NavisWorks and makes working with point cloud files extremely difficult as not everyone has Revit.

[Patrick_Aps_9121]

The way I to this is in a 2 step method:
1) open the cloud (and only the cloud) in Navisworks and save as NWD
2) append the NWD of the cloud to your regular Navisworks NWF model. Select the NWD in the selection Tree and perform a "File Units and Transform" there.
In this manner the distances of the alignment are stored within the NWF and are applied automatically. If you get an update of the cloud you only need to perform step 1 again.

[afinnerty]

Hi - When I save the point cloud as an .NWD by itself this is what I get when I append it into a new .NWF (see attached) - The point cloud is distorted into lines that don't make sense.

Thank you

[Patrick_Aps_9121]

Please clarify:
what file type is your original Point Cloud.
If you start a new NWF and append this cloud, is it visible ?
Then save as NWD
close your navisworks or start a new file.
Open that NWD with the same Navisworks or with Freedom on the same machine, is there already a difference ?

[EricWiens]

Is there a better way to do this?  Or do we have to manually align everything in Navisworks?

We have 10 different scans (we only scanned the rooms in the building, and not the whole building).  We have everything aligned in Revit.  If we have to re-align everything this is going to take hours!!!

Unfortunatly Revit won't let us "walk or fly around" which we really need to show clients stuff.  Navisworks does this.

To make 3D Laser scanning small projects more common we are going to need this feature!!!!

Now to add VR to the mix would be nice too.

[dgorsman]

Fine tuning alignment of point clouds is not something that is done in Navisworks.  The provider of the point cloud would be provided with suitable data to align the point clouds to, using the software appropriate to their scanner, during the registration process.  For example, when we contract for a site scan we'll provide several sets of coordinates for easily identified locations that the scan must be aligned to.

[EricWiens]

I can appreciate that scan's can be registered and have surveyed coordinates etc..

Not all the technologies now have coordinates or registration.  These technologies are suitable for small projects.  For instance you could use a project tango device to create the point clouds, or a dotproduct device, or a drone, etc.  We are not talking about survey grade scanning.  We are talking about technology where the engineer goes to site, takes a scanner with him and instead of taking pictures scans the place.  As a simple example rennovating 3 offices spaces on a floor. 

[christian.storay]

I have a solution for it now. If you want to align your point cloud in Navisworks the same way it's aligned in Revit, this is one way to do it:

When you link that point cloud into Revit, before you start moving it, draw some (non-annotation) linework to mark its origin. I use a specially-made family for this. It's going to be at the Revit origin, so this part's easy once you find it. Then group the origin marker and the pointcloud together and move/rotate the group to match the building.

When the point cloud group is finally aligned to the building, you can measure the differences between the Revit origin and the point cloud origin, and used those numbers in Navisworks (including rotation, though this part can be tricky).

Also, you might know this but I'm mentioning it since Navisworks doesn't warn you when it happens: don't use ' or " in the Units and Transform window. It's just ft for feet, and nothing at all for inches. It will accept fractional inches though, so something like 7’ 4 39/64” will work if entered as 7ft 4 39/64. If you put a " in there it'll ignore the inches entirely and set it to 7ft.

For projects with point clouds already in place, the point clouds will have to be re-imported and aligned again with the origin marked for this to work.

[EricWiens]

Thanks this is helpful.  I guess for now I will have to do it like this.  My issues is we have a current project with 10 point clouds that are aligned in Revit and I just don't want to have to align everything again.  BIM is supposed to solve issues like this!!!

[christian.storay]

Yeah that sounds like a PITA. If your computer can handle it, I'd import the point clouds directly on top of eachother and use the individual points to determine how close they are. You may have to import copied scans with different names.

Also, this method has a lot of room for error. I tried writing a plugin to do it earlier last year but had some trouble figuring it out. Point cloud coordinate locations don't seem to be available in the Revit SDK, yet you can generate an artificial point cloud with fake data... maybe I should have kept digging.

Finally, if you use the Focus.rfa, the center of the square is going to be the origin marker, and the reference planes branching from that point will be what you should latch dimensions to. For pulling elevation, just ungroup the point cloud and look at the focus points elevation property relative to whatever level you have set to 0. The odd shape is for dimension snapping purposes, but I was in a rush. It can probably be done better another way.

[dgorsman]

Regardless of the acquisition technology or process, the result is still the same.  And the same process would be applied to properly register the points to where they are expected in the model.  Thats not limited to traditional surveying although the process behind the scenes is identical.  For what its worth, I consider it a Very Bad Idea to use multiple overlapping scans of the same area without going through the registration process - there's too great a chance for discrepancies when manually aligning them.

Taking in multiple scans, coordinating them, and getting them registered to known points should be possible with the various tools in ReCap, including the auto-registration feature in the "pro" version.

[christian.storay]

Oh I never argued against registration. Obviously that'll be necessary. I don't use Recap Pro for that though, I use Faro Scene. The most I'll do alignment-wise in Recap (non-Pro) is zero the ground floor - but I don't even like to do that because it's impossible to get the same results later when you add new clusters to the point cloud in Scene. What I do instead is carefully move the parent cluster in Scene such that the ground floor is at 0 on the vertical axis - and leave it there. Alternatively, I'll just import it as-is (which will inevitably be a hundreds of feet up thanks to the scanners altimeter... which by the way will never be accurate and is intended purely to assist in registering multi-level buildings), then move it to the building in Revit.

That movement is really all we're talking about. If you move a cluster in Revit, it has to be moved the same way in Navisworks. My original question and what other people here are talking about is exactly that.

Ideally yeah, we shouldn't move the point cloud in Revit/Navisworks at all, but it happens. Sometimes we have to work with other people's models, or within someone else's workflow.

[EricWiens]

Also as I said before, we get random point clouds that don't require registration (ie we don't combine them togeather into one big point cloud).  IE they were built with something other than a laser scanner.  They also don't overlap.  Imagine if I had a point cloud of a bath room, kitchen, and garage in a house with a CAD floorplan.  I would simply use Revit to align the bathroom scan to the location of the bathroom on the floorplan, the kitchen in the kitchen, and the garage to the location where the garage is.  I would then model in Revit any changes I wanted in those area's.

We haven't taken the time to add survey coordinates to the scans so they show up to the right place automatically. Should we be doing this?

[btherrell]

Hi, I read through your help comment. When you say to "open the cloud (and only the cloud) in Navisworks and save as NWD", what file format did you you use when you exported the pointcloud out of you scan software? Thanks

[Patrick_Aps_9121]

There are different options.
1) Faro FLS and Leica PTS and PTX files can be appended directly in Navisworks. The orignal Faro FLS are already registered and do not need any convertion any more. The PTS files can be exported from all other tools that exist.
Start a new NWF, Append a simple CAD file first with a box or some axis lines.
Make sure this is the right origin and units. Then append the cloud. This is needed to have Z upwards in some cases. Directly opening a PTS file can have Y being up for some unknown reason. Hide the CAD mdoel and then you can save as NWD.
2) use Recap. Download the most recent version first. 2.2.0.25 as we speak. Import the clouds in there, skip the registration in most cases. then you can append the whole recap project in Navisworks or first createsome regions in Recap, export each region into a new RCP file and attach that to Navisworks. When using Navisworks 2015 or above, performance and quality of the cloud is much better using Recap.