Do we really need to learn about programmable vertex shaders to do some simple vertex blending ? I set up two world matrices and tried this (abridged for your convinience): 1. D3DRS_INDEXEDVERTEXBLENDENABLE = YES 2. D3DRS_VERTEXBLEND = 1_WEIGHTS 3. SetTransform(D3DTS_WORLDMATRIX(0),&matrix1); SetTransform(D3DTS_WORLDMATRIX(1),&matrix2); 4. Render something Funny! My engine is running as hell, but nothing is drawn. Am I missing some simple point here, or do I need the (very much feared) vertex shader ? By the way, my FVF looks like this: #define VFLAGS D3DFVF_XYZB|D3DFVF_NORMAL|D3DFVF_DIFFUSE|D3DFVF_TEX1 myvertex: float x,y,z; float normal[3]; float blend_weight; /set to .5 for test purpose DWORD diffuse_color; float u,v; My penultimate goal is to round the edges of my cubes Thank you in advance :-)