Anti Aliasing
Anti-aliasing remains somewhat of a mystery. When some of the objects for RCT were created, anti-aliasing was used to make the inner edges less pixelated. This sometimes had the added effect of creating a darker colored outline that can be found on many objects, most prominently found on objects from RCT1.
This dark outline helps to make objects stand out from the background, which can be great for shops, or statues. But less so for wall pieces, which would not be tileable with an outline.
Overall anti-aliasing helps to make objects easier on the eyes. It does however also cause color fringing which can be problematic for recolourable sections.
For RCT1 Simon Foster mostly used Raydream Studio for his renders. One technical limitation of this software was that it wasn't possible to render without a background. This caused anti-aliasing fringing problems when anti-aliasing was enabled. Simon Foster choose a neutral color that could easily be removed using image editing software and that didn't stand out too much[1]. The result of this is that a lot of objects from RCT1 have an outline.
Left: Popcorn stall introduced in RCT1. Right: Chips/fries stall from RCT2.
For RCT2 most objects were made with 3DS Max. In 3DS Max it was possible to render with a transparent background which solved the anti-aliasing fringing issue [2]. Apart from a few exceptions, RCT2 graphics do not have an outline.
These exceptions mostly occur for variants of RCT1 objects. It's safe to assume that the files for the original object were opened and rendered with Raydream Studio to avoid the need for converting them to 3DS Max, and ensuring that the look was the same.
A few examples of where this occurs for objects introduced in RCT2:
- Plinth (Roman floor) from the Classical/Roman Theming. Originates from the floor of the "Roman Temple" object.
- Rectangular liquorice from the Giant Candy Theming. Originates from the top of the "Candy Trees" in RCT1.
Most track types present in RCT2 were originally available in RCT1. For RCT2 only a handful of track types were added to the game. These track pieces do not show the outline.
Tracks that were added to RCT2 and do not have an outline include:
- Powered Coaster (Mine Ride)
- Multi-Dimension Coaster
- Mini Coaster
- Giga Coaster
- Inverted Impulse Coaster
Tracks that got new track pieces maintained their outline. Similarly to new scenery object variants in RCT2 of RCT1 objects.
In addition to that, there're some outliers that were available in RCT1 but do not have an outline:
- Bobsleigh Coaster: This track type does not have an outline this is possibly due to the high detail levels of the channel. The channel is made out of small steel tubes with space in between. Anti-aliasing would have filled that space up and caused the track to not be as see-through as it currently is.
About 85% of all the track types in the game have an outline.
Unlike tracks, nearly all vehicles from RCT1 were either completely redone, or re-rendered with 3DS Max. This is likely due to an increase in the number of frames used for ride vehicles when going through a rotation.
[1] Simon Foster - YouTube
One thing I would say is that I couldn't exclude the background colour from the renders in Lightwave, I found that rendering against black gave me too dark an edge to the images. Rendering against a green or magenta background gave horrible anti aliasing fringing problems. In the end I settled on red 57, green 59, blue 57 for my RGB values. The green 59 was there so that when I magic wanded away the background to transparent, I didn't also lift out any pure grey values of 57/57/57.
[2] Simon Foster - Email
All I can remember is that I used 3d Studio max for RCT 2. I used the primitive default scanline renderer with – I think – a Box(?) anti aliasing algorithm set very low, something like 1.4 pixels. I also made sure that the objects were set to not anti alias against the background so they had a crisp edge to them.