ArchVision Automobiles Volume 1
By Jeff Mottle (jmottle@cgarchitect.com)

Just when you thought you'd seen it all, ArchVision has done it again and has taken RPC content to the next level. The release of their new automobiles product line now adds the ability to place cars into your animations and still renderings. And yes even the wheels turn.

For those who are not familiar with RPC, let me first start by explaining a little bit about this content. I'm sure most of you are familiar with placing bitmaps of people, trees etc. in your renderings. With RPC content you are given the ability to move your camera around the image without losing the perspective of the content you have placed. This is done by placing an RPC placeholder in your scene. At rendertime the RPC plugin determines the location of the camera and swaps out the correct bitmap for that placeholder to match the current perspective. If you attempted to do this with a single bitmap it would not be long before the perspective of your bitmap no longer matched you scene.

The Automobiles line is a new addition to hundreds of existing RPC content types ranging from deciduous trees and sitting people, to walking people and shrubs.

So with that let's take a closer look at the new Automobiles RPC collection. Volume one of this new set includes 8 automobiles: BMW 328 Ci, Ford F-150, Jeep Grand Cherokee, Peugeot 406, Toyota Celica, Volkswagen Beetle, Volkswagen Golf GTI, and the Volkswagen Passat

New settings for the Automobile content are: Speed, Eye Level viewing, Optimize, Wheels, Glass setting and license plate options. There is no cast reflection or billboard option anymore, as all automobiles cast a shadow by default, providing that a shadow casting light source is present, and billboarding has been eliminated due to the nature of the automobile geometry. So what does each of these new options do? I'll get into the new vehicle path tool a little later, but briefly the speed spinner allows you to control the speed at which your car will travel down the defined path. The Eye Level Viewing checkbox allows you to optimize the bitmaps that are loaded, depending upon the angle of your camera. If you are at eye level with the car, you will get more optimized bitmaps for that viewing angle if you enable this checkbox. Conversely, if you are above the car, in an aerial shot, you would want to disable this option. In the pics below you can see how an eye level shot falls apart without this option checked. Pay special attention to the sideview mirrors, the side panels, and the front bumper. While they would look good from far away, if you get close you really need to make sure that you have this checkbox enabled.

Rendered with the Eye Level Viewing turned on



Rendered with the Eye Level Viewing turned off

The optimize checkbox allows you to specify how detailed the underlying geometry for the vehicle will be at rendertime. If left unchecked each car will take up approximately 3000-4000 polygons, but if enabled will reduced this to around 1200 polys. Obviously if you are never going to be up close to you vehicles, checking this box will save you some resources. In the examples below, you can see how the geometry literally comes apart at the seams near the rear window.

The next option is the wheels. This simply allows you to control the direction that the wheels are turned. If you use the path during the insert the wheels will automatically turn to reflect the direction that the car is traveling. In the examples below you can see how this slider affects the steering in a still shot.

Rendered with wheels centered



Rendered with wheels turned all the way to the left.

The second last option is the glass option where you can control the transparency of the glass and the tinting. Yes, you can even tint the windows! The samples below show how how tinting and glass transparency are affected by changing the settings in this area.


Detail showing how you can see through the window of one car to the next. Keep in mind that this is bitmap. Alpha channels are are also affected by the transparency of the glass.


Rendered with moderate window tinting


Rendered with full window tinting

Ok , now the last option, license plates. ArchVision has thought of almost everything for this new RPC collection, including the license plates. You can turn them on or off, use the default RPC plate or create your own. You just simply browse for an image file and voila it get resized to fit on your plate.


Rendered with no plates


Rendered with the default RPCnet plates.
The last area of the review that I want to touch on is the animatable properties of this new collection, as this is how many of you will be using them. When you first insert the automobile placeholder into you scene, you will have to option of setting the location and rotation, as you can with all other RPC types. Once that has been determined, a spline is automatically started from the cars center rear axel that allows you to draw the path that you want the car to follow when the scene animated. The spline is automatically smoothed and you are not limited to the radius of turns that you can drawn, but perhaps you should be. The reason I say this will be quite apparent if you take a look at this small animation. (Click on the image below - 398KB AVI)




You will see that the motion of the front of the car is not very realistic. This is because the car only has one insertion point, and that is at the rear axel. In reality when a car starts turning the car has two paths that it follows. One for the rear and one for the front set of tires. Although this is a limitation for tight turns, large radius turns like lane changes and large sweeping turns still look very realistic. If you had your heart set on creating an action packed car chase scene, you may want to look elsewhere. If you need ultrarealistic car models for your still shots and animated architectural scenes, then these cars are for you. I should also mention that not only can the wheels steer, but they also rotate!



Conclusion

Having spent several hours playing with all of the different options and using them in a production job, I can honestly say that I was very impressed with this new collection. The ability to alter the window tinting, and steer the cars down a road is quite amazing when you consider that this is all generated from a flat bitmap. The cars themselves even display realistic reflection when you move around them.
The only complaints I would have would be the lack of documentation that outline the new features and the selection of car choices and colors themselves. Although the latter is quite subjective, I found some of the cars to be a bit exotic and brightly colored for my own tastes. Of course this is only volume 1 and many more will undoubtedly follow. Perhaps a new release will also allow you to alter the cars paint color? Wait and see.

The price for this collection is $799US and comes with 8 cars. At just under $100 per car I think this is a great deal when you consider how easily you can implement one into your scene and the time and money you would have to spend to get an actual geometry model to look as good.

Overall I'd say this is a great collection worth picking up, and I am looking forward to seeing what new collections are coming down the line.

For more information about RPC Automobiles and other RPC collections, visit:

http://www.rpcnet.com