Procedural Modeling

"Subway"

May 2017

Interior
1280 x 720
Render Time : 4 hours
Min Samples: 1
Max Samples: 5
Exterior
1280 x 720
Render Time: 30 seconds
Min Samples: 1
Max Samples: 9

Assignment

In this assignment, students had to generate a scene with variation.
Guideline/Rules:
  • Provide a sketch or reference image for your choice.
  • Must use Houdini for all aspects of the project
  • Must use the copy node and copy stamping in the project (or the instance node with variations). There should be visible variation of some kind in the individual copies.

Reference Images

I was mainly inspired by the time I went to Paris and rode on the subway for the time. I, more recently, went to Washington D.C. and rode on there subway system.

Parameters

Terminal & Tunnel Tab
Terminal Width
Control how wide the terminal is this may also adjust the width of the platform.
Terminal Height
Control how tall the terminal can become
Terminal Depth
Control how long each terminal can become.
Terminal Spacing
Control the distance between each terminal
Delete Amount on Curves
This controls the closeness of terminals to the corners.
Tunnel Height
This controls the height of the terminal
Tunnel Refine Curvature
This controls the smoothness of the corners
Platform Height
Control the height of the platform
Platform Width
Controls the spacing of platform between the tracks and this also adjust the width the tunnel
Platform Tab
Lamp Tab
Lamp Geometry
User can switch between seeing the full geometry, bounding box lowpoly geometry, or turn of the geometry
Lamp Size
Scale up or down the lamp
Lamp Spacing
Control the distance between each lamp
Railway Geometry
User can switch between seeing the full geometry, bounding box lowpoly geometry, or turn of the geometry
Extend Metal
This is in case the railway spacing is just right but the metal just doesn't reach, the user can extend the metal to achieve a seamless appearance.
Increase Num of Tracks
Increase or Decrease the number of tracks
Railway Tab
Tunnel Light
Light Geometry
User can switch between seeing the full geometry, bounding box lowpoly geometry, or turn of the geometry
Amount of Lights
Control the spacing between each tunnel light

Problems with Solutions

Original Exterior

Original Interior
  • My original plan was to be able to copy one part of the subway and create a curve that the tunnel would curve long. I also thought about how the tunnel would look when it was on the curve and thought about how to connect the end points of one tunnel with another. I eventually googled how people procedural modeled roads and saw that they used a curve to connect the road.
  • I had trouble orienting the terminals properly along the curve. The terminals are copied on each point created by the curve, then I used a resample sop to lower the density of points.  I use the point sop to reorientate which way the points were pointing. My terminals were still turned awkwardly on certain points. Eventually, I began playing around with the resample sop. By default on the resample sop, "Treat Polygon As: Straight Edges" is selected. I changed it to "Interpolating Curve" and it magically fixed my problem. Based on the documentation, Interpolating Curves will smooth out the points from the curve and pass through all the point on the geometry points.

Straight Edges

Interpolating Curve
What Did Not Work
Picture
What Worked
  • I used light instancing on the lamp post's shade. Inside the instance, I used an object merge to point to the sphere sop that created the shade (highlighted in green). That only created one instance. Then I used the add node to create points where each shade was positioned by merging the sphere sop with the add sop (highlighted in red). The gave me a similar resolute. Eventually,  I realized what happened was because I was pointing to the original point and when I looked through the scene view, I could see all of the point created. Even thought I could see all of the points, that is not what the instance was looking at. To fix this, I created a new add node and placed the points where the would have been inside the lamp shade. After that, I copied the same transformation steps that create the lamp. Then I used the output of that information for the instance (highlighted in purple). And it worked!
I used to get random shadows showing up on the platform. I thought it was a texturing glitch. Eventually, I thought back to previous projects and remembered that I did not use an Edge Cusp node to recompute normals.
No Edge Cusp
With Edge Cusp

With More Time...

Here is a short list of things that I want to change, edit, tweak, or do:
  • I want to add objects more to the station, like posters, graffiti, exits, etc.
  • Render an animation with a train