Introduction

Ninety degree curves are one of the most simplistic architectural aspects of a level -- though the simple matter is, many people probably think that it's difficult to create borderline perfect curves without serious mapping work. This tutorial will show you how to easily create a ninety degree turn that should be almost, if not, a "perfect curve." We'll also add some trim to curve -- also prooving that detailing a ninety degree is fairly easy.
Oh, and by the way, there are also a few other great curve tutorials here at the snarkpit -- I highly suggest that you read all of them, since every tutorial out there provides great insight into mapping methodology, and it's great learning experience too! (Please see the bottom of the tutorial for links)

Creating the Basic Curve

We're going to use some slightly large architecture for the sake of this tutorial -- to begin, draw out two 256x256x4 squares, and place them like so as seen in the image. They will serve as the two leeways into our turn.


Next, we need to create a template cylinder to work with -- this will serve as the basis of our turn. I recomend that you use the following settings, as shown here:


Now it's time to draw the cylinder out. Using our two original squares as a template, draw a cylinder out so all sides of the bounding box are all equal in length -- draw the bounding box directly over your original squares, as seen here:


Press enter and create the cylinder -- the result should be this:


Now it's time to slice this cylinder up like a hunk of ham! We'll now create the outter most part of the curve. Using the clip tool, clip and delete 3/4 of the cylinder, until you are left with this:




Now it's time to create the inner part of the circle, using similar methods from above. Once again, create another 16 face cylinder, only this time, draw the bounding box out to the size of the curve we have:


Create the cylinder -- this one will serve only as a template, and will be deleted later. Start off by moving the cylinder down to the bottom corner of the curve, as seen here:


Now create a box that is at least the length of the corner of the cylinder we'll be using. Clip the box along the vertices of the cylinder, as shown here. Note: You will most likely be using a grid of 1 during the clipping process.


Lastly, vertex manipulate the square brushes into place, like so. Note: You will most likely be using a grid of 1 during the vertext manipulating process.


Now delete the inner template cylinder, and tadaa! You've just created a basic, curved, ninetry degree corner. Bask in your glory for just a moment, and then let's spice it up with some trim.

Adding Trim

First, begin by drawing another cylinder that is equal to the area of the curve and both straight paths -- only this time, enlarge the cylinder by 16 units on all four sides:


Press enter and create the circle. Next, you will have to clip off 3/4 of the cylinder. The fourth that should not be clipped away should be the fourth that is resting directly above the curve itself.

Now it's time for some clipping and vertex manipulation. Clip the remaining chunk of the cylinder in relation to the outter most vertices, as seen here: Note: You will most likely be using a grid of 1 during the clipping process. The green dots represent the vertices you should be using to clip against.


Your next job is to vertex manipulate the lowest vertices of the sliced chunk to the outter most vertices of the curve. To fix the triangle sliver we have left over, simply clip off the top of it and vertex manipulate the vertices into place. As usual, you'll probably be on a grid of 1.


The final part is to create the trim on the inside of the curve -- this is really the hardest part of the entire process, though hopefully by the end of this tutorial, you won't be thinking that ;D

Begin by creating two 16 unit wide brushes on the inner sides of our boxes. Not only is this part of the trim that we're trying to create, but laying these brushes down now makes measuring things a bit easier:


Once again, time to create another cylinder! This time, draw out a cylinder that is equal in size to the area of the outter curve, not including the trim. Once you have drawn the cylinder out, shrink it down by 16 units in all directions:


Create the cylinder -- move the cylinder down to our inner curve, and align the cylinder so the fourth that we are going to use matches up on our two rectangles:


We're almost at the end! Wake up! Now draw out a box that covers up the majority of the inside of the turn, and clip it in relation to the outter most vertices of the cylinder: Yea, you'll probably be on a grid of 1 again. The green dots represent the vertices you should be using to clip on.


Vertex manipulate the vertices on the rectangles so the match up with the vertices of the inside of the curve, and the vertices of the outside of the cylinder, like so:


Now delete the cylinder that we have been using as a template. To wrap this up, add some trim to the outside of our two boxes, and you're golden.


That's it! You're all done! Hopefully you've learned, by this point, how to use this cylinder process to create perfect looking ninety degree curves. This method can be expanded on quite a bit, but this is the underlying process you'll be using if you decide to use the cylinder method of creating curves.


Now go create some great curvy architecture ;D

Links

Curves by Dietz
Rounded Corners by Orpheus