[Bf-committers] Could someone explain the Mesh structure in Blender

[Alexander Ewering]

On Wed, 8 Mar 2006, xiang liang wrote:

> I read codes about Mesh, I donot know what each element in Mesh struct
> means.
> can someone tell me how does blender store mesh, use what structure.
> For example. CGAL use half-edge data structure.
>
> MVert may be the vertext list, MEdge may be the edge list, but what is other
> members in structure Mesh mean.
>
> can someone explain it, or give me a link where I can find detialed
> explanation.
>
> typedef struct Mesh {
> ID id;

id: used for storage of the Mesh struct in the library

> struct BoundBox *bb;

The boundbox of the mesh (surprise!)

> ListBase effect;

A list of effects applied to the mesh (again, surprise!)

> ListBase disp;

A list of display lists, I suppose. Not sure.

> struct Ipo *ipo;

A list of IPOs, for vertex keys, etc.

> struct Key *key;

A list of vertex keys (surprise!)

> struct Material **mat;

A list of materials applied to this mesh (surprise!)

> void *mface, *dface, *tface;

tface stores UV mapping, I think together with mface, in some way. About
dface, I'm not sure. This part is pretty chaotic from what I remember.

> struct MVert *mvert;

The vertices.

> struct MEdge *medge;

The edges.

> struct MDeformVert *dvert; /* __NLA */

This stores vertex groups.

> struct MCol *mcol;

This stores vertes colors.

> struct MSticky *msticky;

Sticky coordinates.

> struct Mesh *texcomesh;

Pointer to the mesh giving texture coordinates ("TexMesh")

> float *orco;

Used for texture mapping, storing the original texture coordinates of the
undeformed mesh - or something. Not sure, check the code for the exact
meaning.

>  /* not written in file, caches derived mesh */
> struct DerivedMesh *derived;
>  /* hacky place to store temporary decimated mesh */
> struct DispListMesh *decimated;
>
> struct OcInfo *oc;  /* not written in file */
> void *sumohandle;

sumohandle is game-engine related and stores a handle for the physics
system.

> int totvert, totedge, totface;

Self-explanatory.

> int texflag;

Should be explained further below in the file.

> float loc[3];
> float size[3];
> float rot[3];

Stores texture space transform.

> float cubemapsize, pad;

Not sure about cubemapsize.

> short smoothresh, flag;

Not sure about smoothresh, flag is explained further below.

> short subdiv, subdivr;

Should be clear, SubSurf levels for OGL/Render.

> short totcol;

Total amount of materials on the mesh.

> short subsurftype;
>
> } Mesh;
>
> --
> Liang Xiang
> Email : xlvector at gmail.com
> National Laboratory of Pattern Recognition
> Institute of Automation, Chineses Academy of Sciences
> Address: No.95 Zhongguancun East Road, Beijing, 100080, P.R.China
>


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