Imports can be pinned in projects that have been solved with control points, or that have a coordinate system set up by a scale, rotate, translate or multi-point transform. It is important to verify that you have your scales and sizes are correct. If there is a mismatch between the project’s scale (i.e. wrong control points or wrong scale distance) and the import/object size, you may get a visual line up on the photo, but the object will be in the wrong place. There are a few things to consider with perspective matching by pinning - proper size and units of the import, and proper size, units, and solution of the control points (or the project transform).
If you are having trouble getting a multi-point or multi-ray pin to line up on a photo, it could be the project size/scale is wrong or the import size/scale is wrong (or mismatched units).
It is important to note that most of the pinning solutions do not solve for scale of the import (ie. will not change the import’s size). This has two implications: a) you need to verify that the scale of your project and your import are the same (and the import is in known units), and b) if the scale of your project changes (SRT transform and some action causes S/scale to change), you may need to update your pinning / alignment.
Lastly, a difference between Static Imports and Pinned Imports when it comes to user-defined project coordinate systems (scale, rotate, translate or multi-point) is how they react when the project’s coordinate system definition changes.
A Static Import always remains in the location it was imported and changes in the project transform move around it. For example, if a static import sits at 0,0,0 when imported, it will always sit at 0,0,0 in the world coordinate system even if the project’s transform changes.
A Pinned Import will have its position and orientation updated with changes in the project’s coordinate transform – so that any match to a photo remains. For example, if a pinned import sits at 0,0,0 when imported, it will have its XYZ translation values (as seen in the Pinned Import Transform dialog) change if the project’s transform changes.
A Pinned Import with a free transform with XYZ translate and rotation values set to 0,0,0 and 0,0,0 will act like a Static Import (until the coordinate system changes).