Sunday, 24 February 2013

CG City Construction Techniques

It's been some time since I made a post - busy busy busy.  Anyhow, the submissions for the first phase of the year are now over, and here's what I have thus far:

For 720p & downloads, please head over to Vimeo.

It doesn't look like much at the moment, but a lot of time went into researching cities and finding techniques to build a city.  Of all the techniques explored, I found that simple straightforward poly-modelling will be best for the detailed bits, whilst I'll be using Maya Paint Effects for random placement of building.  Apparently you can also generate random placement of building with nParticles, but I have yet to explore this.

As seen in the above video, I decided on going for a 3-building look for the city, thus having most of the buildings gradually get taller towards the city centre where three giants stand.  In a way, the three buildings represent a podium, and thus also the meritocratic culture of this particular city (and most other cities I guess?).

The initial development phase consisted of a very rough montage that I created by layering and masking cityscape photos in Photoshop.  I then traced a path along the rim of the newly created cityscape, which I used to create a silhouette in order to get a stronger idea of how the city will read.  Finally, I did a rough outline of the buildings for a more concrete illustration of the city.  Here are the three steps:

City Montage

City Silhouette

City Outlines

Onwards to 3D, the first technique I tried was to use a satellite image of New York as a stencil and sculpt the city on a high resolution poly plane in Mudbox.  Didn't quite turn out too well for my current purposes, but I might dive into this one again at some point for super-distant shots (planetary shots, perhaps):

The Stencil Tecnnique: New York

The Stencil Technique - Close-up

Next, I turned to Maya and Photoshop.  I made a random pattern in Photoshop which I converted into a work path.  I then imported the work path as curves into Maya, made some nurbs planes, converted them to poly planes and extruded them to different heights.  It worked fine, but I think some more time needs to go into the initial pattern creation:

The Photoshop Pattern

The Extruded City

Then I gave Maya Paint Effects a go.  I'll definitely be using this technique - just need to model my own buildings and I'll be good to go:

Maya Paint Effects - City Mesh Brush

The final technique I used was the standard poly modelling approach, and since I kept it really simplistic for now (pure poly cubes mostly), it gave me some time to work a bit on rendering techniques.  I applied a sky shader and used a nifty little trick using final gathering maps that took rendering time down from roughly one minute to about 15 seconds (though it did cause some artifacts on the far right building):

Sky Shader (Global Illumination)

All it needs is more buildings... matte time?

And that's that for now.  Next I'll be diving into some architecture research before I start creating more unique buildings in Maya.  But before I go, two things I want to mention:

One: A huge help in discovering techniques for building a city came from a Gnomon Workshop DVD entitled Digital Sets 1: Design, Modeling & Camera - Urban Environments with Eric Hanson.  It's really good and I'll be using it tons for the rest of the year.

Two: Here's a CG short that proves you don't always need an entire studio to do something big (like building a CG city) and serves as a massive piece of inspiration.  R'ha by Kaleb Lechowski:

nethernode, signing off...