...
Paste a list of solid names in Excel column "B".
Append the solid names with ".\3Ds\".
Append the solid names with the file extension, such as ".00t".
Write a logical formula to create the tree structure in column "A".
Insert a line at the top and enter "BEGIN" into cell "A1".
Save as a CSV file.
Rename to a "block3D" file.
Create a folder named "3Ds" in the same location.
Copy the 3D solid files into the 3Ds folder.
Select the block3D file and the 3Ds folder and zip them together.
In Haul Infinity:
Navigate to the Designer tab.
Select Import > Scheduling Blocks from Block2D/Block3D/ZIP.
Import ZIP.
In the Setup Blocks dialog press OK.
If you need to make any changes to the Travel Level in Tree, Travel Alignment or Block Type, you can do it at any time using Configure Blocks (cog) button at the top right of the Blocks tab.
...
5. You will see imported blocks in the Blocks panel as Isolated (marked red), but you may not see them in the viewport. To fix:
Press Top on the compass.
Draw any road segment.
Insert one point, snapping to Plane (E).
Press <CTRL> and click anywhere to insert second point.
Now you should see your imported blocks.