When someone asks whether a map should be “a YMAP or an MLO,” they are usually asking the wrong technical question but a useful practical one: how much interior structure does this project need?
A YMAP stores map data including placements. An MLO is an interior archetype structure that can itself be placed by a YMAP. One does not replace the other. The CodeWalker README explains placement and archetype data; the Sollumz interior guide adds the room and portal structure.
Use a placement exercise to learn placement
If the immediate goal is an outdoor seating area, a few street props or a small arrangement of existing objects, begin with a new YMAP. You can learn the complete edit–export–test cycle without creating custom geometry.
That is why this site starts with a three-prop map. It gives you a clear answer to basic questions: did the server load the resource, did you use the correct archetype, and did you place it where expected?
A small task also exposes workflow problems cheaply. Fixing a resource folder name is easier when the resource contains one new map rather than an entire building.
Use an interior project to learn interior structure
A collection of walls and furniture can look like a room without having an MLO’s room-and-portal organization. Changing a filename or describing a shell as an MLO does not add that structure.
For a custom walk-in interior, plan visible geometry, collision, rooms, connections and the world placement together. The MLO learning path introduces those responsibilities one at a time instead of treating them as a final export option.
The important decision is the behavior you need. Draw the route a player will take and the spaces they should see from each opening. That brief makes it easier to decide whether a simple placement map accomplishes the job or whether you are designing an interior system.
Compare project scope, not buzzwords
| Project | Sensible first exercise |
|---|---|
| Add a small arrangement of vanilla outdoor props | A new YMAP with existing archetypes |
| Add an original decorative object | A drawable, archetype and placement pipeline |
| Build a structured two-room interior | An MLO workflow plus a YMAP placement |
| Replace part of a vanilla location | A scoped investigation of geometry, collision and existing maps |
These are starting points, not promises that every real project fits into one row. Replacements, scripted interactions and edition requirements add their own work.
Do not buy complexity before you need it
A large interior is not automatically better practice. It multiplies the number of assets, connections and dependencies you must diagnose. Start with the smallest environment that proves the behavior you want.
Once you can export a plain room, enter it, cross a portal and reproduce the package, expand it. That sequence gives each new failure a narrower set of possible causes.
For a practical next step, choose your first YMAP or the two-room MLO walkthrough. Both teach mapping; they simply begin at different levels of responsibility.