Entering Values using the Project Base Point

A recent message asked how they can enter values into the Project Base Point (PBP) like we used to be able to do when the PBP had a clipped/not clipped status.

The answer is Specify Coordinates at Point (SCaP).

They wanted to enter 8,000,000/8,000,000 as their example. R2021 won't accept that value but R2019 would.

In the past, when we selected the PBP, entered coordinate values, it actually shifted the Survey Coordinate System (SCS) away from the Origin/PBP. It was easy to assume we moved the PBP because it is easy to overlook the information that displays above the selected PBP. It says PBP but right underneath (see image) it says Shared Site: and the coordinates it displays are relative to the SCS.

Entering values in the PBP directly (in the past) is same as using SCaP (now). The Survey Point will move to mark the 0,0 origin of the SCS after we enter our values. The PBP will still be at the Internal Origin (IO). The following image is 2019 and 2021 showing the same end result, just using a different tool.

Entering values directly into the PBP now will move it away from the IO, something it did not do in the past. This invokes a Local Coordinate System (LCS) that uses the PBP as its origin. Spot Coordinate/Elevation annotation can reference this LCS. This why Revit won't let us move the PBP too far (10 miles) from the IO.

I think Autodesk should change the PBP reference to the Shared Site since it is confusing. I think the PBP should show reference coordinates back to the Internal Origin. There is probably some room for disagreement though, which is why it probably still references the SCS.

This change seems to annoy people the most because we can't just enter values into the PBP directly and get the "old" result. We can enter values but not to alter the SCS, which is what really happens with the clipped PBP of old. The unclipped status of old is when the LCS is invoked.

The PBP only moves in an unclipped state now, thus no clip.

Internal Origin Follow Up

After I shared the earlier Dynamo graph I received an email from Aaron Rumple that did away with any package requirements. He wrote a python script and added it to my graph. It also eliminates the warning message that appears after running mine. The crux of that issue is the need to filter out view templates from the process because while view templates are applied to views under the hood they are also views...at least that's my layman's understanding.

Many thanks to Aaron, a real design software savant.

Download the new Dyn

As before, my graph allows you to include/exclude the internal origin, survey point and project base point. Just edit the settings of the Dyn before running it (see previous post).

Revit 2020.2 - Internal Origin

A quick post to mention this since I've already run into this issue with users several times. The latest update for Revit introduces a new icon to mark the location of the file's Internal Origin. This is what it looks like in the 3D view.

It's off in all views initially, in the stock templates. Reveal Elements will display it quickly in a view without having to use Visibility/Graphics to show it. It can't be selected, it's just visible to help understand where it is.

Edit: It seems existing projects that are opened in 2020.2 have this Internal Origin turned on in all views (many). That's a bug in my opinion. They should not be turning this on. Though, in my own testing it is not getting turned on with upgraded files. It seems to be existing 2020 files that get this turned after opening it with the 2020.2.

Project Base Point - You won't see the clip when you select it. Move it away from the internal origin and it is automatically behaving as if it isn't clipped. In other words, it isn't clipped anymore. We couldn't really move the project origin, only the Project Coordinate System could be adjusted to provide a local coordinate reference for the Spot Coordinate tool, for example.

The Survey Point remains much the same.

When dealing with linked files you'll find that the icons for each of these is also visible but halftone (gray) to differentiate from the host file's own icons. You can snap to the links icon's to help align the files, using the Move tool for example.

I'll have to return to the subject once we've gotten fully acquainted.

Edit: 11/24/2019

I traded a couple emails with Autodesk staff on this. My understanding (not a developer) is this is not merely something they overlooked. Consider when a 2020 file is opened in 2020.2 it is not going through an upgrade because the file format is compatible. This creates a scenario where they are not activating upgrade code to resolve the existing file's structure with a new version's structure.

Unfortunately this new subcategory gets enabled and its visible status is "on" at the outset. It's my understanding that "off" isn't an option...in this scenario...without also creating an upgrade scenario...which is conceptually a no-go...within a release year.

Upgraded files go through an upgrade process which imposes rules on that process...which includes a task that deliberately "turns off" this new subcategory. It's a quirk of the file open sequence/process.

I think they didn't expect it to be a significant issue. It doesn't print after all. It can negatively affect zooming behavior in many views though. User perceptions can't be ignored either. An unexpected "thing" encroaching on views is "bad"...similar to seeing a view's crop boundary when not intended.

To their credit, they asked if I agreed they should create a Dynamo solution to turn it off in all views. Naturally I encouraged them to DO IT! Hopefully we'll be able to say that such a solution exists soon.

Revit Coordinate Systems Video

A lengthy exchange at Autodesk's User Forums about this subject reminded me that I've meant to create a short video to describe how they relate to each other for quite awhile. This morning I saw our cutting boards drying next to the sink and realized they could serve as metaphorical coordinate system planes (Project and Survey) work in Revit. I am curious if readers find it helpful.



The original post at the forum dealt with a few projects that had been modelled very far from Revit's Internal Origin/Startup Location. I looked at one of the project files and found the Survey Point and Project Base Point had been moved very far away while unclipped. The modelling started there, really far far away. They started to experience some of the negative symptoms that can occur and started looking for solutions...thus the original post. The short answer is they needed to move their model closer to the origin. No other way around it.

Clipped or Un-clipped - That is the Question

The question asked: "Steve, should we leave our coordinate system icons clipped or un-clipped?"

My Answer: As we know, the Project Base Point (PBP) and Survey Point (SP) can be un-clipped. If they are untouched we'll find them clipped.

When these are clipped the symbols for each of these are attached to the coordinate systems they belong to. That means moving either while clipped will alter the coordinate system. If this is done unintentionally, or by someone who does not realize they have been adjusted intentionally already, the coordinate system(s) will be changed.

Therefore I'd say it is not unreasonable to leave these in their NOT clipped or un-clipped state at all times, especially after they have been adjusted intentionally to align models or survey data. If they are not clipped then accidental movement of these icons do not alter their related coordinate systems. It merely changes the symbol's position relative to their coordinate systems.

I regard these symbols as markers or annotation when they are not clipped. In this state they are harmless to our coordinate machinations. Clipped they pose a danger to our careful adjustments to align models and site information.

My opinion: Keep them Not clipped, un-clipped.

Survey Point Values after using Publish Coordinates

A RevitForum member remarked that it was confusing to see that the Survey Point shows 0,0,0 after using Publish Coordinates.

The image above shows the initial position, in a Building file, of the PBP and SP after using Publish Coordinates to pass the Shared Coordinate system information from a Site file to it. You can't see a building because they are quite far apart...which is why the icons do not change size when you zoom in/out.

When we open the Building model the Survey Point (SP) is marking its own origin, which is 0,0,0. When we examine the Project Base Point (PBP) we'll find coordinate values that indicate how far away it is from the SP. If we un-clip the SP we can choose to move it closer to the building and we'll see the coordinate values change to show how far the icon is moving away from its origin .

When we use Acquire Coordinates Revit moves the SP (when it is Pinned) to mark the location of the World Coordinate System origin (WCS assuming a DWG site source). When we use Publish Coordinates on the linked Building file it does the same thing but remember the SP is marking the WCS origin, which is 0,0,0 in the DWG...and for the SP of the building model too.

I hear and read the following a lot...

I then test it by removing the linked building model and re-link using shared coordinates and it works.

If you're tempted to do that, just don't do that on real projects since it opens the door to messing up the work we've just done. Just link the building model, re-position it and use Publish Coordinates. Then leave it alone; unless design changes require it to be moved again. A better test? Link the Site model into the Building model using By Shared Coordinates. That doesn't change anything you've done and you'll see they line up properly.

Placing a few spot coordinate annotations on this fine building design, after zooming in closer, looks like this. Also, the one closest to the PBP is assigned to PBP while the others are assigned to the SP.

Revit 2016 R2 - Positioning by Auto - Project Base Point to Project Base Point

This is an interesting development for reconciling the misalignment of models. This gives us the option of linking a RVT model according to the location of its Project Base Point (PBP) and aligning it with our own.

Let's imagine a scenario where our structural engineer decides to mock-up a preliminary model but does so without the benefit of having the architectural model linked in yet. This new feature allows the engineer to either move the PBP un-clipped (see warning below) to an agreed upon grid intersection or to start by placing their grids at the default PBP location in their model.

All I have to do to get their model to align with my model properly now is make sure I move my PBP un-clipped (again see warning below) to our equivalent grid location or be grateful I was lucky to have guessed that we'd start our grids at the same location to start with. If I didn't guess correctly then moving it un-clipped puts it in the correct location and the link lines up nicely.

Being able to move the PBP un-clipped is helpful for Revit to Revit alignment. It DOES NOT address exporting to DWG however (nor appending to Navisworks). If each model is exported using Coordinate System Basis: Project Internal they will not line up with one another because the model's file origin is not altered. If each trade is careful to start modeling the agreed upon grid intersection at their templates's default PBP location (not moved at all) then they'll line up when their exported files are opened in AutoCAD or Navisworks.

I'm not sure we can rely on that if we can't count on them waiting for our model to use as a linked reference first? Still it is an interesting development. Hopefully it doesn't just contribute to the existing confusion regarding linked RVT file positioning.

My recommendations?

• Make sure all trades agree to begin their work referencing their own PBP with the same understanding. For example, agree in advance that the bottom left grid intersection shall occur at the PBP location (like shown in my images). This will ensure that exported data will have the same file origin.
• Don't move the PBP un-clipped to reconcile the PBP location IF you want to be able to export using Project Internal.
• Only move the PBP un-clipped if you will rely on Shared Coordinates to deal with external model alignment in other applications.

Relocate Project is Sleight of Hand

Try these steps:

• Create a new empty project
• Open the Site plan View
• Make sure the PBP (Project Base Point-circle) and the SP (Survey Point-triangle) are visible
• Use Relocate Project, "move" the PBP 1 meter to the left
• We'll find the SP is now 1 meter to the right, left behind marking where the origin was
• The SP identifies the origin of an alternate coordinate system, roughly equivalent to AutoCAD's WCS (World Coordinate System) origin, consider that using Acquire Coordinates aligns Revit with the WCS of the source DWG file.
• The previous steps are essentially the same as moving the SP (clipped) to the right 1 meter instead (use Undo and try it)
• Using Relocate Project you see the PBP move but its really the SP that's changed, it just doesn't look like it because the PBP is reporting a different 0,0 coordinate offset now (more on that below).

In a sense Revit just shifted the world over, underneath our building, and the origin never really changed. If we try the steps above and make sure we can see elevation symbols it becomes more apparent when they don't change their relationship to the PBP after using Relocate Project.

The PBP and SP start out at the same location in stock templates, but they are NOT marking the same information.

The Project Base Point always (when clipped) identifies where the project's origin is. The Survey Point identifies one alternate coordinate system's origin location, when it reports 0,0.

I believe it causes confusion when we examine the PBP coordinate values (when selected) because it displays values that are relative to where the SP defines the WCS origin, NOT the project origin. Since the project origin is never really changing it would be more accurate or consistent to continue displaying 0,0 and only begin showing different coordinates when it is moved un-clipped.

The following image shows a SP that has been moved by Acquire Coordinates to mark the WCS origin of a source survey DWG. The PBP now shows coordinates that match the offset from this alternate coordinate system's origin. To be fair it does say Shared Site: just above the values but it isn't as meaningful to most users as we'd hope.

The following image shows both PBP and SP moved while un-clipped. It is tempting to think of them as points when they are moved like this but they are really annotation referencing coordinates that are only meaningful when compared with where the origins they are referencing are, which I believe contributes to the confusion about what they display when selected.

General Comments and Advice

• The Project Base Point never displays coordinates that reference anything but the Shared Coordinate origin location.
• The Survey Point initially identifies an alternate coordinate origin but it can be un-clipped and moved to show coordinates that reference its origin location.
• The Project Base Point and Survey Point start by marking their own origins, at same location in stock templates but they are NOT the same coordinate systems.
• Don't use Relocate Project for X/Y axis project changes, it's really just establishing an offset relative to the Survey Point, not changing the project origin.
• Don't move the Project Base Point clipped
• Relocate Project can be useful in the Z axis when you need to show an arbitrary elevation value without placing the building at the actual elevations, see True Elevation and Position, it is still sleight of hand though, using Shared Coordinates to achieve the difference.
• Moving the PBP un-clipped can be used with the Spot Coordinate annotation. It can reference the Project Base Point location when it is desirable to mark locations, using the Spot Coordinate tool, that all reference where we've placed the un-clipped PBP.
  

Missing Survey Point

Traded a couple emails with Paul Aubin regarding a client's Survey Point that went missing. It turns out that it had been moved up quite high. I'd never tried to move either the Survey or Project Base Point symbols "up" before so it took me by surprise that it could be done.

Moral of the story, take care when you are selecting things and moving them. You could move your survey point unintentionally.