The learning grind with Pix4D and getting useful data out continues. In QGIS, I can easily align a set of contour lines on top of the orthomosaic. This is probably because neither is geolocated and align at a 0,0 insertion point or (as I hope), both are geolocated at the same point.
In AutoCAD Civil 3D, after setting the correct coordinates system, I am able to insert only the tiles from the Orthomosaic as the merged file (~750MB) is reported as an invalid file. Notwithstanding that I have yet to work out how to merge the tiles to remove the tile borders (another thing to learn), when I insert the DXF contour line file, the file is not seen. Zooming to extents makes everything ‘disappear’ and it transpires that the two objects are - quite literally - miles away. Each one appears as a single pixel and scrolling and scrolling in on each one reveals it to be either the contours or the orthomosaic.
It’s only right to point out that I’m an AutoCAD virgin and every piece of online support assumes a level of knowledge that I clearly don’t have. That said, I can’t fathom why two outputs from Pix4D, taken from the same space on the earth are deemed so far from each other in AutoCAD - anyone have any advice for me (other than “don’t give-up the day job!”)?