Helo

If you want to change the position of the mash, you just
set up matrix, and render mash.

Simething like that:

D3DXMatrixTranslation(&temp,x,y,z);
a
D3DXMatrixMultiply(&matWorld,&temp,&matWorld);

g_pd3dDevice->SetTransform(D3DTS_WORLD,&matWorld);

//Render

Right, you can use matrices and transforms to move, resize and rotate a mesh within your ''world''. It is very easy to use. Understanding it is another matter. :o)

Here is a snippet from my render code:

D3DXMATRIX matTranslation, matScale, matRotation;
int mat;
D3DXVECTOR3 vecLocation;

if(m_pCheckerPieces != NULL)
{
for(WORD wdPiece = 0; wdPiece < (m_wdNumPieces/2); wdPiece++)
{
vecLocation = *m_pCheckerPieces[wdPiece].GetVecLocation();

// Set default translation
D3DXMatrixIdentity(&matTranslation);

// Move to X,Y,Z coordinates
// matTranslation is the location matrix for moving the object around
matTranslation._41 = vecLocation.x;
matTranslation._42 = vecLocation.z;
matTranslation._43 = vecLocation.y;

//matScale is the scaling matrix for shrinking this big mesh
D3DXMatrixScaling( &matScale, 0.03f, 0.03f, 0.03f );

// Rotate on Y
/* matRotation is the rotation mesh for rotating this mesh around. I am rotating 180 degrees and it takes radians so I divide 180 by the number of degrees in a radian (around 57.29 degrees if I recall correctly) */
D3DXMatrixRotationY(&matRotation, 180/RADIAN_TO_DEGREES);

// The order in which these matrices are multiplied is VERY important or the mesh could end up somewhere you don''t want it.
matScale *= matRotation;
matScale *= matTranslation;

// Set the matrix
m_pd3dDevice->SetTransform(D3DTS_WORLD, &matScale);

// Display each material
for(mat = 0 ; mat < (signed)m_dwNumMaterials ; mat++)
{
m_pd3dDevice->SetMaterial(&m_ppMeshMaterials[mat]);

// Activate the appropriate texture
m_pd3dDevice->SetTexture(0, m_ppMeshTextures[mat]);

// Draw the mesh subset
m_pCheckerPieceMesh->DrawSubset(mat);
}
}
}

Hi,

I''m not sure what you mean by dimensions but if you''re talking about the size of the object in R3 space then I presume you want a bounding box or sphere.

The matrix maths isn''t hard but if you don''t understand it you will not be able to produce a good renderer or game. Check out any 3D graphics book or web site and you should have no trouble.