Friday, June 11, 2021

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.

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