Sweep Object Twisting at 90° Angles?

#1

Hello,

I have a linear type Spline in a Sweep object. All of my spline’s points have hard interpolation. I cannot figure out how to get the Sweep to turn in perfect 90° angles without it twisting.

In the scene attached (below), the corners labeled 1 are twisting. The corners labeled 2 are not twisting. I do not understand why and how to control the twisting. The difference I can see is that there is a subdivision between the two Spline points at a greater distance apart. When I add subdivision points using ‘Number’ in my Spline object’s parameters, however, the angles aren’t straight: the corners still twist.

I have tried using a rail spline but I wasn’t able to get clear, consistent results with it. I’ve also tried rotating my Spline’s axis, but that didn’t work.

Can anyone help me to achieve straight 90° corners? Thank you!

Twist
Twist.jpg2087x1465 914 KB

Twist_Settings
Spline_Settings

Spline_Twist.c4d (326.3 KB)

#2

unfortunately there is no really easy answer to that task (as far as I know).
but a railspline might help.
ac06311fb618ec3825d55994f422ff3d2427a9c4_rail.c4d (352.3 KB)

#3

Hi @Jops, thanks for the response. I tried that, but never got a constant Sweep radius. On the C4D Cafe forum, they are calling it a long-time known bug in Cinema 4D, which is a little disappointing.

#4

Yes I saw that. I wouldn’t call it a bug though. It is just a very limited algorithm (a circle that is turned 45° still is a circle, but viewed from one of the main axes it looks like a ellipse).
So mathematically everything is correct. But It is true, that this task is something very common and therefor we all would like to have a propper workflow.

#5

It looks like you don’t have enough line segments on the Spline object. I set the ‘Spline’ to Natural with 6 points and see a much smoother object in the viewport and render. Is there a reason you are using a 12-sided N-sided spline as your circular shape? I don’t know what you are making, but changing the spline setting above should help some.