TBC is a projection based package, which allows it to calculate scale factors, grid and ground coordinates and shift between datums quickly and easily. To calculate this, it sits the data on large spheres which change in size depending on the projection which, changes centroid and the size of the sphere.
The default <Blank Template> inside of TBC is used when no projections are set and allows for real world coordinates to be used while also handling custom scale factors including scale factor 1 (For the purposes of this document we are assuming scale factor 1 is set, but this can be any scale factor defined in the Project settings).
NOTE: It is recommended that <Blank Template> is used over Metric and Metric Scale Only templates as these other templates types handle the data slightly differently and lock out some functionality.
<Blank Template> retains flexibility in the project.
This is used in many different ways, however in scanning jobs if it is desired to be on datum for coordinates but handled at scale factor 1, this is how this can be achieved.
When starting a project with <Blank Template> there is no centroid of the project set, and it relies on the first piece of information to set the centroid of the project and in turn defining scale factor 1 in that area.
For this reason, for a <Blank Templates>, the first piece of data imported should be data in the coordinates the project is desired to be in, so; project data on datum, project control OR a CAD point created in the approximate area of the project.
When importing the data in this way TBC will come up with a message below letting you customise where the centre of the project is if needed (it calculates the centre of the data and uses that otherwise):
Once set any data that sits in the area of the project will be at scale factor 1.
NOTE: If data is imported that isn't on datum, say at 0,0, this will have a false scale factor applied to it. The reason for this is that the data imported is so far away from the centroid and the project coordinates it is no longer in the flat definition of the project.
Moving the data into the project location in this case will mean the data will be handled at scale factor 1.
To update a centroid if needed, a Local site setting can be used allowing for the centroid and scale factor to be moved to the new location.