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Open the Design Space Tool in the Optimisation Tools.
Choose the second method Create Design Space enclosing parts and select the three parts you want to consolidate.
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You can choose the Boundary Offset and Alignment Type and an Offset Factor in the Advanced Properties. In this case an offset percentage a global alignment and a boundary offset of 5% was is chosen to give the optimiser more room to operate.
The input is confirmed and the Tool creates a new part with the initial Design Space.
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