R5K engine
R5K Engine (or R5KE) is a graphics rendering engine project worked on by Cas that aims to provide a new, native graphics engine for Stunts under modern operating systems while preserving its classical qualities.
Capabilities
Slight model incompatilibities
R5KE is based on a painter's algorithm, just like Stunts original graphics engine, but there are a number of differences in their internals. Some of these differences allow the new engine for more flexibility, while others only make things look a little different. Some 3D models will not render the same across engines because the exact workings of the original engine are not known and these models seem to exploit its uniqueness instead of trying to be conservative. This is the case of the lines inside a tunnel or the yellow stripes on ramps, for example. To have R5KE display these models similar to Stunts, one could create some alternative, more conservative models to avoid having to push a lot of exceptions into the new engine's code.
Resolution and viewing distance
In the original Stunts graphics engine, the resolution is always 320x200. With R5KE, the code can be compiled for any resolution and it's possible to make this dynamic. The maximum viewing distance could be configured in some versions of Stunts, but the best quality that could be set was still pretty low. R5KE allows for depth levels that can easily render a complete track.
Track viewer
The currently published implementation of R5KE comes as a track viewer. You need to provide a track file as well as the GAME*.3SH files that result from decompressing the GAME*.P3S original files. This allows you to move more or less freely around the track and view it in high resolution with maximum field depth rendering.
Integration with ReplDump
In March 2023, Daniel3D had the idea of a bridge between ReplDump and R5KE and he wrote to Cas about it. Cas then got to Duplode to ask for some help on ReplDump and began work on integrating the two pieces of software. This forum thread] documents the work held back then. By combining them, it's possible to create images and videos of races from arbitrary perspectives and with several cars running together.