Fighting the construction system to use a specified number of parts

[THX1138]

I have a rocket with eight boosters around it and want to add four more. When the new booster hits one of the eight, it insists on placing another eight but this is not what I want. How do I control this? Thanks.

[SRV Ron]

Try placing two sets of six instead of the eight then four.

[cantab]

Unfortunately, if you place parts using symmetry, you can then only attach parts to them with either the same symmetry or no symmetry.

So you have two options. Either

a) Add your 8 inner boosters with 8-fold symmetry, then add your outer boosters one at a time.

or

Add your 8 inner boosters in two groups each with 4-fold symmetry, then add your outer boosters to one of those groups.

[MockKnizzle]

You could turn symmetry off and place the extra boosters one at a time, but that's generally a recipe for disaster unless you're really careful.