Aligning models

[Bryan Thatcher]

After you merge models, how do you align the two. I didn't think Acad and Revit shared a base point, but I moved the Arch to 0,0 (it was way in the upper left of the CAD file) before linking it to Revit. And mechanical started with a CAD file from us with the way off 0,0. And they appear to be the same distance apart as our CAD and Revit. Please advise. Thanks.

[mitch.cornelius]

I would import the CAD file to revit origin to origin, then see the values of the xyz offsets. Merge the files together in navisworks and and plug those xyz values into the "File units and transform" function

[Bryan Thatcher]

OK, the CAD file comes in 681'-4" off in the X direction and 367'-0" in the Y direction. The settings in the screenshot put the mech model way off and changes the Z direction also. Any suggestions? Thanks.

[mitch.cornelius]

Try entering the dimensions in meters instead of feet.I realize the project units are set to feet, but the origin still shows a (m). Excel or google can each make the conversion for you pretty easily.

[Bryan Thatcher]

Still no luck. I don't know why it's affection the Z value. And would that be a positive X and negitave Y or the other way around? Thanks.

[mitch.cornelius]

I don't know either...It seems I have to try a number of different combinations each time until it works.

[rsloyer]

I would import the CAD file to revit origin to origin, then see the values of the xyz offsets. Merge the files together in navisworks and and plug those xyz values into the "File units and transform" function

I have been doing this very successfully, up until my current project.

For whatever reason, the nwc output from Revit of the model has a different origin than the Revit model itself. In fact, the model is even rotated 90 degrees in the vertical plane!

I was able to export a dwg file that maintained the same origin as the Revit model, and then move the origin in the dwg to where I wanted it, but using the dwg file in Navisworks is very far from ideal for a variety of reasons.

I exported a dwf file from Revit after using model slicer to get the parts of the building I wanted and the selection tree is fantastic, even better than the tree you get from an nwc export, but it has the same shifting origin point problem.

Since the files come into Revit differently than they come into Navisworks, there is no accurate way to scale the difference and get the into the right place.

[jspartz]

Measure from the location it's at to the location you want it to be in Navisworks than highlight the file and use the transform objects button in the measure tools. Sounds easy, but usually isn't. You need a matching location in each file, like crosshairs or a box to align with when measuring. I typically transform the Revit model because I have way more AutoCAD models and those are easier to align.

[rsloyer]

Measure from the location it's at to the location you want it to be in Navisworks than highlight the file and use the transform objects button in the measure tools. Sounds easy, but usually isn't. You need a matching location in each file, like crosshairs or a box to align with when measuring. I typically transform the Revit model because I have way more AutoCAD models and those are easier to align.

Therein lies the problem, which is the measure in Navisworks sucks. I have gotten pretty good at the snaps, but it's still nowhere near as good as it needs to be from a contractor's perspective. I have subcontractors that won't even try to use measure because they've gotten so frustrated with it.

[jspartz]

I know what you mean. I add crosshairs for each file, turn off everything else, zoom in as far as possible and pick. Then unhide the items before selecting and doing the transform. It's never off more than 1/256" - typically it's unreadable (displays 0" difference).

[rsloyer]

That is more or less what I wind up doing. I'm not a CAD guy by any means though and it's agonizing doing that. I know that I'll get better at it but it stinks to have to do it at all.

[payre]

To allign I draw 3D boxes at same coords, not croshair or grid lines. Then to snap exactly at 3D vertex, make sure snap to vertex is on, set tollerance to 5, and you get a lovely vertex symbol when you hover near the vertex alowing you to snap exactly to that point.

[justins.205223]

I didn't see it mentioned, but is it possible that your NWC settings are set to export to a shared coordinate? That coordinate system could be different than the project origin, so it could be exporting to a completely different location than you think it might be.

[rsloyer]

How do I get to NWC settings?

[RobertB]

How do I get to NWC settings?Since we are talking about an export from Revit, you do this from the Revit addin.

[Teresa.Martin]

In terms of alignment, you can use the measure tool to move data sets that are out of alignment. Generally what I tell clients is create an object that is 2'x 2' by 20' higher then the tallest point of the building. Te bottom corner of the object should sit at the intersection of grid lines 1 and A in each trades respective data sets. Or this object should sit with its lower corner at the origin.

Call the object OBELISK. In Autocad, you can put it on a layer called OBELISK. Why OBELISK? Because you will never see any other object in any of your data sets with that name unless you are doing a retrofit of the Luxor Hotel in Las Vegas.

All you need to do after you import all the data sets is line up the OBELISKs upper left corner. Very easy to do with the measure tool. This is the easy, 2 cent solution folks.
By the way, you can easily create a selection set or search set that will allow you to select all the OBELISKs and hide them once you are done. After you have moved a dataset, you can go to Selection Tree, select the file, right click and choose File Units and Transform. Make a note of the x,y and z origin change and rotation if any. The next time you replace this file, you can just enter the coordinates without having to use the measure and transform command.

I hope this helps!

[justins.205223]

How do I get to NWC settings?

After you click on the NWC Exporter in Revit, the 'Export Scene as...' dialog box should pop up. There is a button for 'Navisworks Settings' at the bottom. In the File Readers > Revit section, change the Coordinates settings to 'Shared'.

[rsloyer]

In terms of alignment, you can use the measure tool to move data sets that are out of alignment. Generally what I tell clients is create an object that is 2'x 2' by 20' higher then the tallest point of the building. Te bottom corner of the object should sit at the intersection of grid lines 1 and A in each trades respective data sets. Or this object should sit with its lower corner at the origin.

Call the object OBELISK. In Autocad, you can put it on a layer called OBELISK. Why OBELISK? Because you will never see any other object in any of your data sets with that name unless you are doing a retrofit of the Luxor Hotel in Las Vegas.

All you need to do after you import all the data sets is line up the OBELISKs upper left corner. Very easy to do with the measure tool. This is the easy, 2 cent solution folks.
By the way, you can easily create a selection set or search set that will allow you to select all the OBELISKs and hide them once you are done. After you have moved a dataset, you can go to Selection Tree, select the file, right click and choose File Units and Transform. Make a note of the x,y and z origin change and rotation if any. The next time you replace this file, you can just enter the coordinates without having to use the measure and transform command.

I hope this helps!

I like this idea, and yes it helps very much. I can have my subcontractors add this object to their models, and I can add it to my BIM standards going forward so that I know they are all including it. I think I would need to dictate the height myself, however, just to be sure they are all the correct height, otherwise people will start scaling off of the wrong "highest point".

[Teresa.Martin]

Hi! Yes, you can choose any height you like, just make it tall enough so it sticks up past any other structures so you can find it easily. And yes, I find this and easy to use, very visual way to align datasets. Anyone can do it. It is not elegant, but it works!
Best regards,

[rsloyer]

Having an odd issue with this.

In Revit I select "Component" and "model in-place". I choose the generic category and name it "Obelisk". I then choose "Extrusion" and draw a 2'x2' box in plan view, and set "Extrusion Start" to 0' 0" and "Extrusion End" to 100' 0". I finish the model and go to the elevation or section view where I can measure the model and see that it is 100' tall.

What gets hinky is when I export to Navisworks. I export the file, open it in Navisworks, and now the Obelisk is only 68' tall. The rest of the model is the correct size/scale as evidenced when other models are appended and line up in the appropriate places (pipe in wall penetrations, equipment sitting on pads, etc.).

What is wrong with my Obelisk?

[Teresa.Martin]

That is odd behavior. It should come in at 100' if everything else is scale correctly. Are you zooming out in the 3d view so you can see everything including the obelisk? Do you have the section box on by chance? I cannot think of anything else off hand that would cause this behavior other then what I just mentioned.
Anyone else care to weigh in here?

[rsloyer]

Section box was the issue.

This Revit model is something I got from the design team and added the Obelisk to, and there are some very strange things afoot with this model. Finding a view I could use was difficult and then figured out they had the section box turned on.

[rsloyer]

New problem, same topic.

I have three Revit models from three different sources, essentially created in a vaccuum from one another. I export them all to .nwc files. I then open the first in Navisworks, then append the other two. When I click on any area of the view cube, they all disapear. If I select one of them in the selection tree and click an area of the view cube that one model apppears, highlighted.

This would seem to indicate to me that the models are all nowhere near each other and that in order to view the entire file from the view I select on the cube it has to zoom so far out that the individual models are only tiny specs.

Any ideas how to get them better aligned?

[Bryan Thatcher]

If you have access to the Revit model, reset the Project Base Point and Survey Point close to the model, than re-export. That's where I would start.

[rsloyer]

If you have access to the Revit model, reset the Project Base Point and Survey Point close to the model, than re-export. That's where I would start.

Yes, I do have all three Revit models, and I've inserted Obelisks into all three. I will look into how to reset those items.

[kellpy67719556]

I would import the CAD file to revit origin to origin, then see the values of the xyz offsets. Merge the files together in navisworks and and plug those xyz values into the "File units and transform" function

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