Circular settings in Alias

00:00

Here I've got four 360° revolves from exactly the same curve.

00:05

But if we display the geometry, you can see that I've got some quite different results in terms of the CV layouts and the surface layout.

00:15

And if I display some locators, you'll see that the accuracy is also different, depending on the structure of the geometry.

00:22

So, if we have a look at the settings that we used in this one, we've got Non-Periodic with just one segment.

00:29

And that means we've just got a simple NURBS surface looped around to create an approximately circular shape.

00:36

So, it's very efficient in terms of CVs, but not very accurate in terms of being a circle.

00:41

So here, we've used four segments, and we've also increased it up to 6° so that each segment only has to describe 90° of that circle.

00:53

This one here has been created as a Periodic surface,

00:56

which means that if I pick any of the holes and make any changes to them, they will behave equally as if the revolve is a closed loop.

01:06

And you can see that the accuracy here is reasonable enough for concept modelling.

01:11

Finally, we have a Rational setting in our Construction options, which takes away your option of having Periodic or Non-Periodic.

01:20

And it's built with weighted CVs that give your revolve accuracy, but that make it not very practical for sculpting due to these sharp edges.

01:29

So, the two options I will generally use most are splitting into four segments—or however many segments you want for accuracy—

01:38

or using a Periodic, if I want to later on sculpt the shape and keep it as a coherent loop.