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Next, you have to associate this variable with the object properties. This requires a little bit of thinking. The height of the two cylinders must be set equal (50mm - gap_h)/2. This makes the total height of your structure h<sub>tot</sub> = (50mm - gap_h)/2 + gap_h + (50mm - gap_h)/2 = 50mm, as you want. In [[EM.Cube]], the local coordinate system (LCS) of a cylinder is always set up at the center of its bottom base. As you vary "gap_h", the bottom of "Cylinder_1 " will always stay fixed at Z = 0, while the bottom of "Cylinder_2 " must be located at 50 - (50mm - gap_h)/2 = 25mm + gap_h/2.
Open the property dialog of "Cylinder_1 " and set its height equal to "gap_h". Then, open the property dialog of "Cylinder_2", set its height equal to "gap_h" and set its Z-coordinate to "25+gap_h/2".
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