Latest revision as of 04:04, 26 January 2012

[edit] Overview

This is a Sims 3:RCOL chunk for Body Geometry.

[edit] Format

DWORD 'GEOM'
DWORD Version			// 5
DWORD tgi offset		// see Sims 3:Key table
DWORD tgi size			// see Sims 3:Key table
DWORD EmbeddedID		// if no embedded material, will be 0
                                // otherwise, if the "morphskin" or "morphskincloth" shaders are used in the material, it will be the FNV32 hash of "SimSkin",
                                // and if the "morpheye" shader is used, it will be the FNV32 hash of "SimEyes"
--if (EmbeddedID != 0):
	DWORD ChunkSize
	--insert MTNF chunk	// follows the same format of MTNF from Sims 3:0x01D0E75D, starting at the 'MTNF' tag

DWORD mergeGroup
DWORD sortOrder                 // often zero

DWORD NumVerts			// Number of vertices
DWORD FCount			// Number of vertex elements
--repetition FCount:
	--insert Vertex Format	// see below
--repetition NumVerts:
	--insert Vertex Data	// see below

DWORD ItemCount                 // will usually be 1 (hardcoded in pipeline exporter), but sometimes other numbers
--repetition ItemCount:
	BYTE BytesPerFacePoint

DWORD NumFacePoints
--repetition NumFacePoints:
	BYTE[BytesPerFacePoint]	// Given that ItemCount is 1, BytesPerFacePoint is 2, this is a list of WORDs
				// Each set of three forms a face.

DWORD index 			// to a Skin Controller(0x00AE6C67)

DWORD count1
--repetition count1:
	DWORD bonehasharray	// 32-bit hash of used bone names.

--insert TGI Block List	// see Sims 3:Key table

[edit] Quirks

This format is packaged in a RCOL container, however doesn't adhere to the same standards that most do.

• Declares a null resource key(00000000:00000000:0000000000000000) making it harder for tools to generically infer what type it is.
• Contains a "Standard" TGI List, rather than using the built-in RCOL external references
• Due to using the standard list rather than the scoped RCOL list, references made in the MTNF are interpreted differently
• Pets EP introduced animal meshes that tend to have more than 1 uv-channel per mesh(uncommon or non-existent in previous human meshes)

[edit] Vertex Format

DWORD DataType
DWORD SubType
BYTE BytesPerElement

[edit] DataType

[edit] SubType

You calculate the offset of each element from the sum of the previous BytesPerElement

Based on contributions from karybdis and atavera

[edit] Vertex Data

[edit] Reading Vertex Data Blocks

For each vertex, you need to loop through the VertexFormat as defined, and read the information in order.

The order can be completely arbitary, and varied in size.

Here is some example code in c# to do so:

for (int i = 0; i < numVerts; i++)
{
	for (int j = 0; j < vertexFormats.Count; j++)
	{
		float x = 0;
		float y = 0;
		float z = 0;
		vertexFormat vf = (vertexFormat)vertexFormats[j];
		switch (vf.dataType)
		{
			case 1:
				x = reader.ReadSingle();
				z = reader.ReadSingle();
				y = reader.ReadSingle();
				sb.AppendLine("  XYZ: " + x.ToString() + " " + y.ToString() + " " + z.ToString() );
				break;
			case 2:
				x = reader.ReadSingle();
				z = reader.ReadSingle();
				y = reader.ReadSingle();
				sb.AppendLine("  Normal: " + x.ToString() + " " + y.ToString() + " " + z.ToString() );
				break;
			case 3:
				float u = reader.ReadSingle();
				float v = reader.ReadSingle();
				sb.AppendLine("  UV: " + u.ToString() + " " + v.ToString() );
				break;
			case 4:
				sb.AppendLine("  Bone: " + reader.ReadUInt32().ToString() );
				break;
			case 5:
				float w1 = reader.ReadSingle();
				float w2 = reader.ReadSingle();
				float w3 = reader.ReadSingle();
				float w4 = reader.ReadSingle();
				sb.AppendLine("  Weights: " + w1.ToString() + " " + w2.ToString() + " "
					+ w3.ToString() + " " + w4.ToString() );
				break;
			case 6:
				x = reader.ReadSingle();
				z = reader.ReadSingle();
				y = reader.ReadSingle();
				sb.AppendLine("  Tangent Normal: " + x.ToString() + " " + y.ToString() + " " + z.ToString() );
				break;
			case 7:
				// Note, not splitting this up yet just reading an int
				sb.AppendLine("  TagVal: " + reader.ReadUInt32().ToString() );
				break;
			case 10:
				sb.AppendLine("  VertexID: " + reader.ReadUInt32().ToString() );
				break;
		}
	}
}

Note that basically we just look through the VertexFormat, and read the data in order. There is no fixed "vertex format" version, it's all controlled via the vertexformat data.