GMDC

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===GMDC Model Data File Specs===

These are most likely the actual 3D models since they tend to be the largest files (besides textures and animations).

this file type uses the Resource Collection format RCOL.

Examples found in ""The Sims 2\TSData\Res\Sims3D\sims03.package""

This file type uses the standard RCOL header, generally having no file links and only 1 block.

The simplified header looks like this but a program should probably use the more general form. 4 new ID flag: This may or may not be there(see RCOL) 4 file link count (0) 4 index itemcount (1) 4 block id (0xAC4F8687)

followed by the GMDC block AC4F8687 cGeometryDataContainer

cGeometryDataContainer (GMDC) written 6-jan-2005 (WesHowe) latest update: 03-Feb-2005

The GMDC contains the actual shape (mesh) data that defines an object in the game. It uses the standard RCOL format, described elsewhere. What this page will describe is the data model it follows and the known usage of these elements within TS2.

There are three top-level structures; the General Header, Block Header and the Contents Section. The first two relate closely to the general RCOL format. The Content section was designed to support 3D object data.

Almost all of the first two structures, except for the version and the filename, seem to be invariant in TS2. When I create a GMDC I just copy a fixed block of everything up to the filename length in one fwrite() [I only output as version 4]. The remainder here is a data definition and values discussion, up to the limits of what I know.

0x1c4afc56 :mod1=2 mod2=0 0x3b83078b :mod1=2 mod2=1,3 - Normals list (3 x float) 0x3bd70105 :mod1=0,1,2 mod2=0,3 - Bone weights (1, 2 or 3 floats per vertice) 0x5b830781 :mod1=2 mod2=0,3 - Vertices list (3 x float) 0x5c4afc5c :mod1=0 mod2=0 0x5cf2cfe1 :mod1=2 mod2=3 - Morph Vertex Deltas 0x7c4dee82 :mod1=2 mod2=1 0x89d92ba0 :mod1=2 mod2=3 - Bump map normals (3 x float) 0xcb6f3a6a :mod1=2 mod2=3 - Morph normal deltas 0xbb8307ab :mod1=1 mod2=2,3 - UV coordinates (2 x float) 0xdb830795 :mod1=4 mod2=2,3 0xdcf2cfdc :mod1=4 mod2=3 - Morph vertex map

Identities are used to identify data list type

Mod1 and Mod2 - valid values are 0,1,2 or 4. Mod 1 values 0,1,2 mean floats 1, 2 or 3 times #records, 4 means dword 1 time # records (credit darkmatter) If identity=0x7c4dee82 mod1 will be 2 and mod2 will be 1 but the above rules sometimes don't apply

0x3bd70105 :mod1=0,1,2 mod2=0,3 - Bone weights (1, 2 or 3 floats per vertice) (matching above assignments) 0xdcf2cfdc maps each vertex to a small int, which then keys into the morph vertex and normal data lists (1 for first pair, 2 for second, etc.) to find float values to be added to the original vertices and normals to modify the mesh for fatbelly, pregnant, etc.

It also appears that most of these types must be there, even if empty, to satisfy the game loader.

struct Linkage {                           '' P2
   long          LkIndexCt;                '' # of entries to follow
   short         LkIndexData[LkIndexPtrCt]; ''  if (version==4)
   long          LkIndexData[LkIndexPtrCt]; ''  if 
	                                      '' ((version==1)||(version==2))
   long          LkVerticeCt;             '' number of vertices in the model
   long          LkActiveCt;              '' This seems to be the same as P2IndexCt
   long          LkBlockBCt;              '' number of entries that follow
   short         LkBlockB[LkBlockBCt];    '' if (version==4)
   long          LkBlockB[LkBlockBCt];    '' if ((version==1)||(version==2))
   long          LkBlockCCt;              '' number of entries that follow
   short         LkBlockC[LkBlockCCt];    '' if (version==4)
   long          LkBlockC[LkBlockCCt];    '' if ((version==1)||(version==2))
   long          LkBlockDCt;              '' number of entries that follow
   short         LkBlockD[LkBlockDCt];    '' if (version==4)
   long          LkBlockD[LkBlockDCt];    '' if ((version==1)||(version==2))
   }

The Transform count, if present, matches the total number of Subset structures. Each is a set of 7 floats. The first 4 are a quaternion (X,Y,Z,W) and the last 3 are translation values (X,Y,Z). Usage discussed in the Subset section below.

struct Subset {                         '' P5 - structured following bone assignments
   long         VerticeCt;              '' if zero, empty Subset
   long         FaceCt;                 '' number of subset faces times 3
   float        Vertices[VerticeCt][3]; '' data block
   short        Faces[FaceCt];          '' if (version==4)
   long         Faces[FaceCt];          '' if ((version==1)||(version==2))
   }

This section contains subsets of vertices and faces for the model for animated models. When this section is used, the ModelData section may or may not contain a full or partial set of name pairs, but seems to be empty of Vertices and Faces. It will contain a set of transforms, to relocate each subset to match the main model. To apply the transform, you subtract the X,Y,Z values (last 3 floats) from each vertice, then use the quaternion to build a matrix and apply a rotation to the vertex.

I have found that you can build a usable non-animated object GMDC by using Vertices, Normals, UVs, faces and building a composite model. Animated models can be built by adding in Bone assignments and bone weights, adding the appropriate ModelData Transform data (P4), and building a subset model (p5) by bone assignment. All the other parts can be empty, but certain morph data will not be available.