Anyone who wishes to use third-party maps for SE should use the notes below to guide conversion, or specific modifications that get close to achieving the same result. Much of the notes will revolve around making Yuri's Revenge maps work with the mod, beyond the basic .yrm to .mpr file renaming.
Since SE has extensive urban theater changes, the custom terrain, many URBAN maps will encounter artefacts that can be removed if unnecessary, or altered in one of several ways, the best options will be listed as a rule. This will be true for maps made with RA2 and YR in mind, but the major terrain errors are more common among early RA2 maps.
There are now tools out that can modify maps correctly when changing theaters, and for replacing one kind of object with another. Such tools will come in handy when making these conversions, however many of them can be made by simply editing the map in a text editor. It is worth noting that missing buildings or units or trees on the map will not cause the game any problems, missing overlays however will cause a hard crash.
Note the map size limitations for RA2 is much smaller than YR, and YR supports a lot more waypoints, so if any scripting on the map uses waypoints above 100, expect to crash also.
The most common problems facing URBAN maps will be the use of rubble tilesets, such as Washington Rubble, the use of Bright Pavement where Clear could be used, and changes to the cliffs.
In the case of rubble tilesets, most of them have been replaced with new terrain that doesn't look at all like it, and likewise doesn't occupy matching sizes. For this case, it is best to merely overwrite all the offending tiles with Clear. To replace the missing rubble, simply add the correct (or similar) buildings to
the same locations with a strength of zero. This will force the buildings to show their rubble as if they were destroyed.
Bright Pavement has been modified to be more like broken paths or flagstones, and now includes bits of grass within the cells, which makes for excellent walkways in a meadow, or as a neglected foundation for an object like a water tower. The immediate problem on the map will be that the pavement isn't complete, and the tileset was typically used on maps to show rundown or dirty sections of pavement, rather than as something unique. The effect of this is seeing those grass bits within perfect Clear tile sections, which looks out of place, and the simplest option is to replace all such broken tiles with Clear. Then choose where to use the Bright Pavement tileset selectively.
One obvious deficiency of the original urban theater is that it lacked a complete set of cliffs for making symmetrical raised sections, whether as a box for two bridges to connect, or for just keeping cliff corners consistent across all axes. To make more perfect cliffs, there is a tileset called Concrete Cliff Fixes which will provide many of the missing corner pieces, inside and outside corners. This tileset also includes some off angles to be able to make rounder cliff areas, like a monument or special building platform, and also includes graffiti pieces for decorating an otherwise clean urban landscape.
There is a further tileset called Water Cliffs C, which has replaced some Miami rubble, which provides some of the above fix pieces for use with water cliffs.
Lastly, while not so much a conversion bug as a side effect of general terrain changes, ramps will often appear as a mix of grass and concrete tiles, which can be fixed by using the ground levelling tool nearby, the influence of the tool will correct the odd corners. This fix however exposes the change, that ramps are now grass instead of concrete by default, and grass hills or valleys will be made instead of the previously strange paved mounds. This may require a change in how the maps are designed to take full advantage, but as the Slope Set pieces remain concrete, the paved cliffs with paved slopes will not be affected.
As per above, when levelling raised or lowered ground, another side effect occurs, sometimes Clear tiles will show up in place of the previous grass. Unfortunately, no fix for this exists, the resultant Clear tiles just need to be filled with the Grass tile. In FinalAlert2 holding Ctrl while left-clicking acts like a fill tool, which is the best way to fill large areas of Clear tile.
SE has included all the default arctic tilesets from YR, including the ice cliffs, so in most cases arctic maps will require minimal terrain work, if at all.
There appears to be little to no change between RA2 and YR in this theater.
The popular TX/TX 2.x which added a number of deprecated objects and tilesets for making the most of YR, often with the help of Ares, is totally incompatible with Scorched Earth. Any maps designed with TX in mind will probably be a massive pain to make operate with SE's urban theater, and it would make more sense to start a new map instead. Due to the extensive use of overlays and additional trees, it may also be quite the headache to make SE's maps work with any other mod, whether it uses TX or not. As mentioned, missing overlays (such as rocks) will crash upon loading the map, and SE maps often have a lot of additional overlays, or have additional frames within existing overlays.
Scorched Earth has the majority of buildings from YR added, but in many cases the art and even foundation size was altered. In a few rare cases, there was no valid application for the building in SE, or the foundation is unsupported in RA2, and was thus omitted. In a few cases, they could be added at a later date, but for now they are too superfluous to focus on.
Below is a list of [BuildingTypes] and their SE substitution:
CABARR01->TANKBAR1 (TerrainTypes object)
CABARR02->TANKBAR2 (TerrainTypes object)
CASIN03E->SIGN1 (TerrainTypes object)
CASIN03S->SIGN2 (TerrainTypes object)
CAURB01->CAURB01 (TerrainTypes object)
CAURB02->CAURB02 (TerrainTypes object)
CAURB03->CAURB03 (TerrainTypes object)
CAPARK03->MERRY (TerrainTypes object)
CAMSC11->TIRES (TerrainTypes object)
CASTRT05->BSTOPNW,BSTOPNE,BSTOPSW,BSTOPSE (TerrainTypes object)
CAMSC13->TANKHUSK1,TANKHUSK2,TANKHUSK3 (VehicleTypes object)
Below is a list of [VehicleTypes] and their SE substitution:
FTRK->PUMPER,FIRETRUCK (for airports)