Relationship between: File Settings > Working Units: (a) Linear Units vs (b) Advanced Settings Resolution vs (c) GCS defined units (Geographic Coordinate System)

Hi Neil,

well, you opened quite complex question ;-)

Neil Usefara said:

the 3 types of units of measure

They are not "units of measure" to be precise. In fact, it's about mixing different concepts and to compare apples and oranges.

Neil Usefara said:

that are displayed in Design File Settings and GCS.

It would be nice to follow, as Jon asked, the best practices, and to specify used product, its version, and also to provide more precise information what setting do you mean. To share e.g. a picture of dialog or a link to documentation, where the setting is described, makes the discussion simpler and more efficient.

Neil Usefara said:

Advanced Settings Resolution Units

General recommendation is "do not touch them", because when you will change them, you will (A) probably corrupt existing model (because its size will change) and (B) there are some consequences when DGN V8 is exported e.g to V7.

These settings describes how values (coordinates) are stored internally in DGN V8 and also provide some basic information what they mean. Default values fit (I guess) 99,9% of scenarios. To change the setting is possible, but it's recommended to know very well how DGN V8 format is designed and what consequences are.

Neil Usefara said:

Linear Units

They are units you choose to work with. They do not tell anything more than when a value is used to express a coordinate, what it means for the user (which, typically, is equal what it means in real world).

Working units have no relation to how coordinates are stored, because they are converted into UOR (units of resolution) at background. In other words, when one model uses meters and another millimeters, internal value can be the same.

Neil Usefara said:

GCS

GCS system is built on top of working units, and as you wrote, it adds extra information about used geographic coordinate system.

With regards,

  Jan

However you set them, it is important to start off with the correct settings in your seed file. Trying to update any of the units in files that have data in them can be a real headache. We went through that with a lot of companies in the upgrade from MicroStation V7 to V8. 

Jan Šlegr said:

Neil Usefara said:

Advanced Settings Resolution Units

General recommendation is "do not touch them", because when you will change them, you will (A) probably corrupt existing model (because its size will change) and (B) there are some consequences when DGN V8 is exported e.g to V7.

These settings describes how values (coordinates) are stored internally in DGN V8 and also provide some basic information what they mean. Default values fit (I guess) 99,9% of scenarios. To change the setting is possible, but it's recommended to know very well how DGN V8 format is designed and what consequences are.

I always make sure the advanced units definition matches the master unit definition (Meters - Meter, US Survey Feet - US Survey Feet, etc.).

This setting us used by the GSC definition. If you're attaching a GCS defined in Meters to a model whose Advanced resolution is set to Feet you will get the following

Any time you're attaching a GCS whose units do not match your advanced resolution definition you will get a similar dialog.

I don't think that is exactly what Dave is asking. Your report is run on one file and reports references attached to that one file. So if you have 150 files you want this information from, you would have 150 reports - or did I read it wrong ?

what I believe Dave wants is an overall way of getting the information from many files into one report instead of having just one report per file - or did I get that wrong also ?

Tim - you are correct. A process that would open each DGN/model in a directory and create 1 report showing Working Units, Resolution Units, Global Origin, Geographic Coordinate System, 2D/3D for each DGN/model

I had a VBA years ago that did something like that. I can't seem to find it just now. If I remember correctly it wasn't all that hard to do. The tricky part was interpreting the Master/Sub units from VBA into something a normal person would understand.

Tim Hickman said:

Your report is run on one file and reports references attached to that one file. So if you have 150 files you want this information from, you would have 150 reports

As I wrote, it's an example.  I don't know if MicroStation reports can be run on multiple files, but it would be useful.

David Allen said:

A process that would open each DGN/model in a directory and create 1 report

We had a QA tool that did something similar...

That tool was for V8 and there are no plans to migrate it to CONNECT.

Thanks Rod / Thanks Tim

I didn't intend to hi-jack Neil Usefara's thread... but I do feel that if we can somehow quickly determine this information on a group of files, it would be very helpful with isolating files that are using settings that do not to conform to the project settings.

To expand on Jan's explanations above...

Linear Units: Defines the Unit of Measure in MicroStation and MicroStation-based products. Master units are significant where sub-units are less important (more of a user preference: Civil uses decimal feet and architects/structures use fractions of a foot/inches). Which Units (and custom units) are "available" can be defined in an external/configured units.def file. DGN files using different units can be referenced together (MicroStation does the conversion), but I try to avoid if/when possible. All units in MicroStatipon are based on the Meter.

Resolution Units: Defines the size of the Design Plane (2D) (3D = Cube) Pre-V8 DGN, this was defined by pixels 2-32nd power x 2-32 power. User could define the size of a pixel represented, i.e Meter, foot, mile, inch, etc. - which determined the "size" of the Design Plane/Cube. Because this was pixel-based, this was less accurate/did not meet IEEE double-enhanced precision. In my opinion, Resolution in V8/CONNECT units are a carry-over from pre-V8. In my opinion, Units used to define Resolution should match units used to define Working Units

Geographic Coordinate System (GCS): Determines where your project (coordinates) is. States in US may share the same coordinates - but when you define GCS, now MicroStation knows where the project is (in relation to the world system). Most GCS in USA are based on metric units - and then published in Metric units and imperial units (Feet, US Survey Feet) units. Different states use different projection methods. As mentioned, the GCS units must match DGN Working Units - or you will get a unit mismatch alert

Global Origin: Where on the Design Plane/Cube your model is located (center of Design Plane is typically most desired/most accurate)

All of these settings should be set in the seed files/models used for any project. 2D/3D is also set in the seed files/models

Reference Attach - Coincident: Aligns files using coordinates only

Reference Attach - Coincident World: Aligns files using coordinates and global origin

Hope this helps?

Thanks Rod / Thanks Tim

I didn't intend to hi-jack Neil Usefara's thread... but I do feel that if we can somehow quickly determine this information on a group of files, it would be very helpful with isolating files that are using settings that do not to conform to the project settings.

To expand on Jan's explanations above...

Linear Units: Defines the Unit of Measure in MicroStation and MicroStation-based products. Master units are significant where sub-units are less important (more of a user preference: Civil uses decimal feet and architects/structures use fractions of a foot/inches). Which Units (and custom units) are "available" can be defined in an external/configured units.def file. DGN files using different units can be referenced together (MicroStation does the conversion), but I try to avoid if/when possible. All units in MicroStatipon are based on the Meter.

Resolution Units: Defines the size of the Design Plane (2D) (3D = Cube) Pre-V8 DGN, this was defined by pixels 2-32nd power x 2-32 power. User could define the size of a pixel represented, i.e Meter, foot, mile, inch, etc. - which determined the "size" of the Design Plane/Cube. Because this was pixel-based, this was less accurate/did not meet IEEE double-enhanced precision. In my opinion, Resolution in V8/CONNECT units are a carry-over from pre-V8. In my opinion, Units used to define Resolution should match units used to define Working Units

Geographic Coordinate System (GCS): Determines where your project (coordinates) is. States in US may share the same coordinates - but when you define GCS, now MicroStation knows where the project is (in relation to the world system). Most GCS in USA are based on metric units - and then published in Metric units and imperial units (Feet, US Survey Feet) units. Different states use different projection methods. As mentioned, the GCS units must match DGN Working Units - or you will get a unit mismatch alert

Global Origin: Where on the Design Plane/Cube your model is located (center of Design Plane is typically most desired/most accurate)

All of these settings should be set in the seed files/models used for any project. 2D/3D is also set in the seed files/models

Reference Attach - Coincident: Aligns files using coordinates only

Reference Attach - Coincident World: Aligns files using coordinates and global origin

Hope this helps?

This thread also seems helpful for this discussion:

(57) Working Units [FAQ] - MicroStation Wiki - MicroStation - Bentley Communities

Here is another article that, while focused on a particular set of units, explains a little bit about how units are defined, an relate to one another: https://communities.bentley.com/other/old_site_member_blogs/bentley_employees/b/tim_hickmans_blog/posts/survey-feet-vs-international-feet