Creating Smooth Wireframes with Maya
Ever wanted to create a nice smooth wire frame of your Sub-D or NURBS surface without dishing out the cash to buy a
plugin? Well, this is a simple process to do just that.
This tutorial will just be quick and dirty, explaining itself mostly through pictures. Let's begin.
The method is fairly simple. The first piece of the puzzle that you'll need is a render of your scene / object.
For this example I'm using a hat. And yes, there is a hole in the side of it. Don't ask. :) The next piece of the puzzle is a nice,
smooth wire frame of your scene. Now, before you do this, it might be a good idea to save your scene under a new filename,
because we're going to be making changes that you might not want to save to your master scene file.
Set your 3d view background colour to pure black.
Now, make sure that "Wireframe on Shaded" and "Smooth Wireframe" are both enabled in your viewport. Also, now might be
a good time to set the display tessellation of your wire objects. For NURBS just hit 3, or set your shaded divisions to
something high like 8. With Sub-D, you can only use up to level 2 preview display quality (hit 2 when a Sub-D object is
selected) because level 3 will introduce more lines where necessary and will not be an accurate reflection of your wireframe.
Next, create a new display layer and set its layer colour to white.
Add all the objects you need wireframes for to the layer (and hide any other objects that you don't).
After adding the objects to the layer, de-select them and all their wire frames will be white. If you have objects that are in
front of the object you want a wire on, then just create another new layer, but this time set its layer colour to black and
assign the objects in question to it.
Next, we need a pure black surface shader. Create a new one and apply it to everything. See now why I told you to save?
Now we have a wire frame view of the scene perfect for using as a transparency map in Photoshop. Time to transfer it. The
first thing you'll want to do is turn on your resolution gate, to use as a guide for cropping the screen shot you're about to
take. Once that's done, crank the resolution of your monitor (or, if you have extended desktop capabilities, you can use that
instead), hide all of Maya's UI elements (Display->UI Elements->Hide All UI Elements) and take a screenshot. In Windows
this can easily be accomplished by pressing the Print Screen key. We want to do this so we can get as much resolution out of
the wireframe to create the smoothest one possible. Ideally, you'll want to use a resolution 2-3x larger than your render's
dimensions. Keep in mind, however, that the larger the gap between the render resolution and the screen shot resolution,
the thinner the lines will be. Create a new document in Photoshop and paste the screen shot. Crop the screen shot around
the inside of the green square that popped up when you turned on the Resolution Gate (under View->Camera Settings-
>Resolution Gate in any perspective camera viewport).
Now resize the wireframe down to the exact dimensions of your original render. Don't worry if auto-proportions in Photoshop
has the dimensions off by a pixel or so. The green box isn't exactly perfect, but it's certainly close enough. If this is the case,
just turn off constrain proportions in Photoshop's Image Size dialog to force the resolution to match your render. Use the
highest quality resize filter available. In Photoshop 8 CS I recommend Bilinear Sharper.
Depending on the difference in resolutions from your screen shot down to your render resolution, the wire frame might be a
bit faded. Not a big deal, just apply a levels adjustment to brighten it up.
Take a look at the screenshot below. I've used the wire frame mask we've just created on a solid black colour layer, and the
result is a solid black wire on my original render.
The best thing about this method is that it gives you a white on black mask to play and be creative with. The picture below
uses an over-exposed version of the render as a wire colour.
Another idea is to apply the wire mask to the render's depth channel (you'll need to enable rendering depth channels in
maya, and install the Maya IFF Plugin for Photoshop to access that channel) to give an effect similar to the picture below.
That's it! It is a little bit of work, but the result is worth it, and unless you're rendering animations of wire frames, it will save
you from dishing out too much money for a plugin to accomplish the same feat. I hope this has been useful. If you have any
questions, feel free to send me a private message on the cgtalk.com boards. My username is visjes and I will respond as
quickly as possible. :)
visjes on cgtalk.com
http://graphics.tu-bs.de/people/richter/tutorials/Hidden_line_removal_rendering_in_Maya - The original method http://www.
alias.com/eng/community/downloads/index.jhtml - Maya IFF Plugin for Photoshop