Saw an old thread discussing about how to do Generals-styled dozer construction in C&C3, so I decided to take up the challenge. This is what I managed to achieve: Basically, it works the same way as the dozers in Generals: select the construction unit, build a structure and place it within the indicated building radius it provides. However, this method also revealed an unfortunate engine limit, which is that if the building radius exceeds the player's visibility and goes outside the Fog of War, then it enables the player to place the structure anywhere on the map, even if there are existing structures or any other obstacles at the placement location under the fog. So I had to reduce the building radius of the dozer so that it's smaller than its vision range.
After placing the structure, the dozer will automatically go to the placement location to complete construction. And the good news is, the AI knows how to use this as well! However, a bigger hindrance popped up, which could cause even more severe gameplay problems. While the dozer unit is on its way to the placement location, it will ignore any new command issued by the player, including telling it to go to a new location, or skip the current construction to build something else.
As such, I'm not sure if I should go on to finish implementing this mechanics, since there are so many flaws with the current iteration.