Collisions for XModels

[Laupetin]

Unfortunately #789 does not fully implement collision support yet. You can get collisions to work with it however if you borrow collSurfs and contents from the original models (when testing by rebuilding a model with all xmodels from disk), the collisions work as expected.

This means these fields must be handled for collision support.

[michaeloliverx]

What exactly does this mean? Is it related to clipmap collisions? Or collision with bullets or something? How could it be tested and verified in game?

[Laupetin]

What exactly does this mean? Is it related to clipmap collisions? Or collision with bullets or something? How could it be tested and verified in game?

The one effect that I noticed and tested with was:

1. Rebuild IW3's mp_showdown with all xmodels loaded from raw (GLB)
2. Go behind one of the big wooden boxes that lead into the central area from either spawn
3. When trying to shoot the boxes you will shoot through them and bullet holes will appear on the ground behind them because bullets go straight through

This is not the case when either

• not loading the xmodels from raw
• loading them from raw but replacing collSurfs, numCollSurfs, contents with the original data

[michaeloliverx]

Dumped the raw data for all of mp_showdown and it is a LOT of data present. Had a deep dive into how the official mod tools produce this data. I found the producer in the stock deffiles/xmodel.dll. Asset Manager’s collisionLOD really does select one of the regular XMODEL_EXPORT LODs for bullet collision. When that LOD is converted, the converter walks every triangle, requires each triangle to be rigidly attached to one bone, rejects degenerates, and groups the triangles by (surface, bone). It transforms them into bone-local space and generates the plane/svec/tvec collision representation plus bounds.

contents and surfFlags are copied from the selected LOD surface’s material properties. The values in stock raw/material_properties match the dumped collSurfs exactly.

The result is embedded in raw/xmodel/<name; xmodelsurfs remains the render geometry. So this is separate from the .map/clipmap compiler path and is specifically the detailed XModel bullet-collision path.

Solutions could be preserve dumped data and then add stock-equivalent generation from the selected GLB LOD when that sidecar is absent.

[burgertownloserville]

can I use collision files dumped by greyhound