1. Understanding the problem
All data in your file must be georeferenced, if any elements are not they will remain located at the origin (0,0,0), the location of which is defined by your project Coordinate Reference System (CRS).
The origin can be very far away from your project site, which means that that "bounds" of your file can be enormous which in turn can cause issues with both navigation and visualisation.
If clicking on the helicopter (see below) brings you to a random location this is likely the problem.
2. How to remove unreferenced data (using AutoCAD or Civil 3D)
Open CAD file in AutoCAD or Civil 3D.
Click and drag a selection box around the data/model extents.
Type "explode" into the command bar and hit enter - this will split all linework into individual components.
Draw another selection box around the data/model and type "wblock"
Select a filename and save destination along with filetype (.dwg or .dxf) and export as usual.
3. What is a project Coordinate Reference System (CRS)?
Every project on Sensat has a CRS. To view what CRS your project is using, go to you settings (your photo or initials at the top of the right-hand toolbar) and select Project settings. A CRS is a series of mathematical rules that defines the location of a point (X, Y, Z) in a defined space and ensures that different sets of geospatial information within a project (e.g. a pointcloud and a CAD model) can align with one another correctly.
In the example below the project CRS is 27700:
You can check where the origin for any CRS is using this website: https://epsg.io. The origin (0,0,0) will always be located at the left-hand bottom corner of the rectangle: