Page 15 Modeling a Tank: Body Detail

With the side bool objects still selected drag them in the top view about 35 units up so that they intersect deeper into the side of the tank.

BooleanDifference the side bool objects from the tank side. If you plan on showing the far side of the tank you can Mirror the objects over to the far side before booleaning the near side. But if you're not sure right now create a layer and copy the side bool objects and ChangeLayer them that hidden layer. For this exercise we're just doing a still image with the far side hidden.

Select the curve shown below.

Extrude it up about 2 grid lengths and BooleanDifference it from the tank body to get the result shown below.

Turn on the 'mech detail curves' layer and turn off the 'body boolean curves' layer.

Select the curves shown below.

Extrude 'Cap=Yes' the curves beyond the sides of the tank as shown below.

Note: When the curves are planar and you have 2 curves, one inside the other then the extrusion will be tubular in nature.