How can anyone do this Shanghai tower

[Anonymous]

Hi, how can you do this triangular sort of sloped vertical plane in this example of the shanghai tower (see picture extreme left). has anyone done this? how about the 3rd bldg. from the left? how to create that slot at an angle.

[ToanDN]

Imagine you take a knife and slice the tower to several slices horizontally.  Now draw the cut profile of these slices at where they were cut make a form.  The more slices you have, the more accurate the form will be.

[chrisplyler]

Screencast coming up soon...

[chrisplyler]

Oh...while you're waiting...

The slot can be done with a void form after the fact, or as I did it here, by just including the notch into the the lower and upper shapes prior to making a form out of it.

[chrisplyler]

Aaaaaaaaaannnnnnndddddd here we go...