Church Model

Ray Tracing Project

CPSC3710

Presented by:

Mark Geiger

The following image is of the church from the position and view angle I chose to model.

The next two images are my model of this church, each from a different angle. The first image is my attempt at replicating the original photo of the church. The second image is from a different angle which I chose to expose some of the extra design that went into the creation of the model which cannot be seen clearly in the first image.

I chose to do my project using Google’s SketchUp. I modeled the Mormon church in Fairmont because I believed that the building’s symmetry, as well as its abundance of basic geometric shapes made it ideal for a ray tracing model given the time constraints and my level of experience.

To create my model, i began with a large rectangle, then sloped the roof by pulling the middle up into a peak. I used symmetry to my advantage in construction as much as possible. I cut away the right side of the building at the very beginning of construction. Then I constructed all of my doors, windows, textures, shapes, and colours on the left side of the building. When finished, I made a copy of the object, flipped it, and glued it to the opposite side. After that I constructed the front and back of the building, then constructed and added the steeple. Some areas of difficulty include doors, windows, the arched roof of the side entrance, the ball at the point of the steeple, and overall size and scale.

Creating doors in SketchUp is fairly simple, as it involves only adding some design to a rectangle. However all of the doors on the church I chose to create had elaborate patterns of glass. SketchUp is mostly designed for user convenience so when an area becomes bordered it is filled in with white, becoming a 2D object. The problem is that much of the time, the windows on my doors were seen as separate from the door, so I would end up with transparent windows on top of a white background. I dealt with this problem for many of the doors and windows on the model until I became more familiar with the design tools.

The arched doorway on either side of my model was another source of frustration while building my model. The first problem arose when attempting to get the proportions right. Either the roof would be too steep, the pillars too close together, the arch too wide, or the door too small. This was a learning experience as I realized that in the future I would have to take measurement and dimensions of objects into account while modeling (which indeed became very tedious). Once I had the rough shape of the doorway, I decided to add some trim to the roof. The problem is that the tool used to do this has trouble with curved surfaces, so I had to cut away a small portion of the arch on the inside of the doorway on either side. Also the pillars were in the way, so I had to move them which brought back the problem of scaling and proportions.

One of the issues I had with SketchUp, which is a trivial problem in other programs such as POVRay, is that of dealing with spheres. Although it is difficult to see in the picture, there is actually a small ball at the peak of the steeple. Actually creating a sphere in SketchUp is far from intuitive to begin with. In POVRay, one would simply declare a sphere, then translate it to the desired location. In SketchUp, creating a sphere includes intersecting two circles so that they are perpendicular to each other, then using the follow me tool in SketchUp to tell one circle to follow the other. It is somewhat difficult to intersect two circles in SketchUp, as the program attempts to draw the circle on top of surfaces, such as the original circle. But once you have your sphere, it is another even more difficult matter to position it. In SketchUp, edges have markers such as endpoints and midpoints which the object you are moving will attempt to snap to. This is a useful feature with cubes and squares and other flat faced objects as you can create guides for them to snap to. The problem with a sphere is that every point on the sphere is seen as an endpoint, so positioning it correctly is very difficult.

Scale was always a problem in designing my model. In fact, while creating my building, I kept making everything so much larger than it was supposed to be. By the end of construction, a very small length relative to my building (the width of one pillar in the doorway), was in reality very long when using the measuring tool (pillar greater than 1.5 meters wide). Since the church was the only thing I was constructing, this is not a problem as I can simply rescale the model as a whole now that construction is complete, however if I were designing more detailed models, say with trees and other buildings, I would have to be more wary of size and scale.

For this model I used only the tools, textures, and patterns that come with the free download of Google SketchUp 7. All objects in the model were created by me.