MeshShape collision

MeshShape (0xB22B3E61) stores triangle collision separately from render Mesh resources. A byte-counted section run contains geometry and adjacency, followed by materials and bounds. Evidence includes two different-size fixtures, a 15,222-body section census and a 724-shape tree analysis. Observed

MeshShape body9 + L + tailRR44% known

Little-endian. Offsets are relative to this structure.

ProvenObservedSourcedInferredUnknownNot described

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0x0

ManagedObject byteu8 = 01

UserCategoryu32

E37A7DC2 length Lu32

0x9

E37A7DC2 (the sections)bytes

9+L

tailbytes

Offset	Size	Type	Field	Confidence	Notes
0x0	1	u8 = 01	ManagedObject byte	Unknown	Stored bytes; meaning is not established.
0x1	4	u32	UserCategory	Observed	ObjectShape.UserCategory (registry enum UserResourceCategory, a u32, the base class's field, stored first): 0 (389), 63 (239), 33 (96) of 724 sampled; the same enum as the last u32 of a Mesh. Enumerators: 0 _Unknown, 33 ENV_Prop, 63 ENV_Procedural.
0x5	4	u32	E37A7DC2 length L	Unknown	Stored bytes; meaning is not established.
0x9	L	bytes	E37A7DC2 (the sections)	Unknown	Stored bytes; meaning is not established.
9+L	var	bytes	tail	Observed	the Tail box

Sectionsize bytesRR100% known

Little-endian. Section framing, face/material counts and tail buffers read across all 25,162 MeshShapes of the six installed forges with no refusals. Tree decoding semantics remain scoped to 724 sampled shapes.

ProvenObservedSourcedInferredUnknownNot described

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section typeu16

markeru16 = 0xECD7

sizei32

0x8

payloadbytes

Offset	Size	Type	Field	Confidence	Notes
0x0	2	u16	section type	Proven
0x2	2	u16 = 0xECD7	marker	Proven
0x4	4	i32	size	Proven	its 8 header bytes included
0x8	size-8	bytes	payload	Proven

Sections in order (payloads)varRR

Little-endian. Offsets are relative to this structure.

ProvenObservedSourcedInferredUnknownNot described

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0x0201 descriptorchar[n]

var

0x0301bytes

var

0x1EEE countsu32·3

var

0x1EEF positionsf32·3V

var

0x1EF0 facesu16·3F

var

0x1EF1 per-face polygon idsu16·F

var

0x1EF2 face edgesu32·3F

var

0x1EF3 edge facesu16·2X

var

0x1EFA bounds and node countf32·6 + u32

var

0x1EF9 tree nodesbytes

Offset	Size	Type	Field	Confidence	Notes
0x0	var	char[n]	0x0201 descriptor	Observed	NUL-terminated 'Name(0x<id>) MeshDescriptor'
var	8	bytes	0x0301	Unknown	Stored bytes; meaning is not established.
var	12	u32·3	0x1EEE counts	Observed	V, F, X
var	12·V	f32·3V	0x1EEF positions	Observed
var	6·F	u16·3F	0x1EF0 faces	Observed	position indices
var	2·F	u16·F	0x1EF1 per-face polygon ids	Inferred	u16 per face, from 2 up to F+1 (724 of 724 shapes). Faces that share an id are coplanar in all but 27 of 37,036 shared groups: the id numbers the planar polygon a face belongs to (a reading; behaves as face-group ids)
var	12·F	u32·3F	0x1EF2 face edges	Observed	edge ids
var	4·X	u16·2X	0x1EF3 edge faces	Observed	0xFFFF where an edge has one face
var	28	f32·6 + u32	0x1EFA bounds and node count	Observed	size (x, y, z), then minimum (x, y, z), then the node count F-1. The minimum equals the vertices' minimum, and the size is at least the vertices' extent (equal within 1e-3 relative), on 724 of 724 shapes; the u32 equals F-1 on all 724 and is the number of tree nodes in 0x1EF9
var	11·(F-1)	bytes	0x1EF9 tree nodes	Observed	Node 0 is the root; every node 1..F-2 is the child of exactly one node and every face 0..F-1 is a leaf of exactly one node, on all 724 shapes. The 6 quantised bytes are not decoded

Tree node (11 bytes, ×(F-1), section 0x1EF9)11 bytesRR100% known

Little-endian. Offsets are relative to this structure.

ProvenObservedSourcedInferredUnknownNot described

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child insetsu8·6

child Au16

child Bu16

flagsu8

Offset	Size	Type	Field	Confidence	Notes
0x0	6	u8·6	child insets	Observed	byte k (k = 0..5: minimum x, y, z, maximum x, y, z) is the inset, in 255ths of the node's decoded extent on that axis, of the child named by flag bit 2+k; 0 at the root on the shapes read
0x6	2	u16	child A	Observed	a face id if flag bit 0 is set, else a node id
0x8	2	u16	child B	Observed	a face id if flag bit 1 is set, else a node id
0xA	1	u8	flags	Observed	bit 0: child A is a face (else a node); bit 1: child B is a face

Tail42 + m + 10n bytesRR100% known

Little-endian. Section framing, face/material counts and tail buffers read across all 25,162 MeshShapes of the six installed forges with no refusals. Tree decoding semantics remain scoped to 724 sampled shapes.

ProvenObservedSourcedInferredUnknownNot described

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OneCollisionMaterialOnlyu8

MaterialUniqeIndexu8

IndicesMaterialData count mu32

0x6

IndicesMaterialDatau8·m

6+m

TriangleMaterialData count nu32

10+m

TriangleMaterialDataref·n

10+m+10n

MinLocalAABBoxvec4

26+m+10n

MaxLocalAABBoxvec4

Offset	Size	Type	Field	Confidence	Notes
0x0	1	u8	OneCollisionMaterialOnly	Proven	MeshShape.OneCollisionMaterialOnly (registry bool): 1 on 668 of 724 sampled (one material), 0 on 56 (a material per face)
0x1	1	u8	MaterialUniqeIndex	Proven	MeshShape.MaterialUniqeIndex (registry spelling, a byte): 0 on 724 of 724 sampled
0x2	4	u32	IndicesMaterialData count m	Proven	0 (kind 1) or F (kind 0) (MeshShape.IndicesMaterialData, an array of bytes)
0x6	m	u8·m	IndicesMaterialData	Proven	index into the references, covering 0..n-1
6+m	4	u32	TriangleMaterialData count n	Proven
10+m	10·n	ref·n	TriangleMaterialData	Proven	every one a CollisionMaterial 0x74F7311D (registry array of CollisionMaterial)
10+m+10n	16	vec4	MinLocalAABBox	Proven	the positions' box; w 1.0 (registry vec4)
26+m+10n	16	vec4	MaxLocalAABBox	Proven	w 1.0 (registry vec4)

Across the 724-shape tree sample, root node zero reaches every node and face exactly once; all non-root nodes have one parent. The six inset bytes describe child-box sides in 255ths of the parent’s extent, and flag bits 2–7 select the inset child for each side. Observed

Shared ids in 0x1EF1 group coplanar triangles in all but 27 of 37,036 shared-id groups. Interpreting the ids as polygon ids is supported by that fit rather than a declaration. Inferred

OneCollisionMaterialOnly selects a single surface; otherwise IndicesMaterialData has one byte per face indexing TriangleMaterialData. The spelling MaterialUniqeIndex follows registry metadata. Observed

What explains the exceptional shared ids?

Noncoplanar groups prevent a universal polygon-id invariant. The eight zero bytes of section 0x0301 also have no established meaning. Unknown

The complete six-archive section reader accepts all 25,162 MeshShape entries; the more detailed tree and polygon-id meanings above remain scoped to the 724-shape sample. Every section and tail is byte-accounted, without refusals. Proven · framing only

Shaun White Skateboarding

only in SWS

Collision geometry is a MeshShape object (0xB22B3E61) with explicit triangles, held apart from the render meshes. The vertices are stored as float4 with a zero fourth component, the triangle indices as u16 triples, one surface byte per triangle, and an opaque Havok MOPP acceleration blob that needs no Havok packfile to read the triangles. The shape is in its own local frame, Z up. Observed · SWS[level 01]

MeshShape fields (Shaun White Skateboarding)variableSWS

Little-endian. Fields in stored order after the object prefix; exact on 1,561 of 1,561 shapes read.

ProvenObservedSourcedInferredUnknownNot described

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Verticesu32 + f32[4][n]

var

MoppCodeu32 + bytes

var

MoppOffsetAndScalef32[4]

var

IndicesTrianglesu32 + u16[3][t]

var

IndicesMaterialu32 + u8[t]

var

Materialsu32 + u32[s]

var

filterCollisionFilterInfo

var

MoppCodeVersionNumberu32 = 5

var

local boundsf32[4][2]

Offset	Size	Type	Field	Confidence	Notes
0x0	4 + 16n	u32 + f32[4][n]	Vertices	Observed	w is 0
var	4 + m	u32 + bytes	MoppCode	Observed	the Havok MOPP blob, kept opaque
var	16	f32[4]	MoppOffsetAndScale	Observed
var	4 + 6t	u32 + u16[3][t]	IndicesTriangles	Observed
var	4 + t	u32 + u8[t]	IndicesMaterial	Observed	one index per triangle into Materials
var	4 + 4s	u32 + u32[s]	Materials	Observed	bare ids of collision surface objects
var	var	CollisionFilterInfo	filter	Observed	an inline box, class 0x43EF99C2
var	4	u32 = 5	MoppCodeVersionNumber	Observed
var	32	f32[4][2]	local bounds	Observed	minimum and maximum

The Havok SDK that produced the MOPP blob is unknown. The data is neither a packfile nor a tagfile. Observed

Other collision shapes occur in cells: capsule, sphere, box, a convex shape (BarrelShape), a list shape (ListShape, 0x86EBFD8D, whose body ends with a flag byte) and a MultiMeshShape (0x9A503477). Observed

Rigid bodies and placement

A prop’s collision is an InertComponent (0x0E5A450A, 150 bytes in 1,561 cases) on its entity: the component base, a damage enum, an inline RigidBody (0x228F402A: a CollisionFilterInfo box with layer and part, the shape id, mass, linear and angular damping, four flag bytes and a 16-float local inertia tensor) and a walkability enum, then 12 bytes. The managed byte of the inline body can be 0. RigidBody.Shape is a bare id; level 01 reaches 1,152 shapes inside the cell and 409 in other entries. The inertia tensor is not the placement. Observed · level 01

A MultiInertComponent (0x8BBEEE57) holds an inline MultiMeshShape of parallel arrays: five-byte entity handles (tag 0 and a u32) and bare shape ids. The container itself carries an identity matrix in the cell examined; each pair is placed at its contained entity’s matrix. The pairing matched on a cell of ten children: the six shapes that resolve locally have exactly the names of their entity’s Visual meshes. Observed · one cell of ten children

Level 01’s collision placements number 2,074, of 1,194 unique shape objects with 49 distinct surface ids, and every shape and entity reference resolves. Observed · level 01

What has no collision

Collision belongs to an entity through a component (an InertComponent, a MultiInertComponent, or the class of the kickers below); an entity with only a Visual component is drawn and has nothing to stand on. Observed · SWS Large drawn areas are of that kind: level 03’s background hills (03_Island_BG_Ground_01 to _05b) are Visual-only, except _04b, whose collision is 16 flat triangles; level 06’s 06_Ground_Construction_01 covers about 79,000 m² of upward-facing render with no collision; SW_RoadB and SW_RoadC have none either. Observed · SWS Level 03 has no heightfield or terrain class among the 73 object classes of its forge, and of its 276 distinct MeshShape ids 273 are placed; the other three belong to props. Observed · SWS[level 03]

Sampling every upward-facing render surface on a 2 m grid against the placed collision (a render sample counts as covered when collision lies within 1.2 m) finds uncovered ground in every level. The counts include roofs, ceilings and background cliffs, so they bound the walkable gaps from above. Observed · SWS

Level	Collision triangles	Upward render samples within 12 m of collision	Uncovered	Confidence
01	123,102	35,219	10,244	Observed · SWS
02	106,174	57,257	21,756	Observed · SWS
03	96,361	16,055	5,726	Observed · SWS
04_Stronghold	15,332	5,120	1,904	Observed · SWS
05	134,172	32,565	15,299	Observed · SWS
SW	44,347	4,519	848	Observed · SWS

Kickers, ramp boxes and shaping grinds (*_InfGP_Kicker_*, *_RampBox*, ShapingGrind_*) carry a component of class 0x0873AE87 instead of an InertComponent. Observed · SWS That their collision is a free-form hull of class 0xC3120087 is a guess. Inferred · SWS

Level 03 places 19 00_OutOfBound_Air_Trig_* slabs (8 × 1 × 10 m) along its district edges. Observed · SWS[level 03] Whether they respawn a player who leaves the collision is not established. Unknown

Can the player reach the Visual-only ground?

Whether the game keeps the player off the uncollided hills and roads, through the out-of-bound triggers or otherwise, is not established.