Hello, I cant seem to get this working as I require. Anyone tell me why ? (Really sorry if this is mega simple, I am learning and trying to get this working). The stuff below relates to my vs and ps in an fx file. The fx file has this at the top - float3 lightpos; // light position in world coordinates The vertex shader has this in it - float4 pos=float4(IN.pos.x, IN.pos.y, IN.pos.z, 1.0); OUT.pos=mul(pos, world_matrix);// world_matrix = rot, scale, trans of object float4 lp = float4(lightpos.x, lightpos.y, lightpos.z, 1); OUT.lightpos = lp; OUT.normal=mul(IN.normal, world_matrix); And the pixel shader does this - float3 l = normalize(IN.pos-IN.lightpos.xyz); float3 normal = normalize(IN.normal); float diff=saturate(dot(l, normal.xyz)); return diff; Now I am trying to get some clubs that are in the hands of my skinned creature to diffuse correctly. Now the qeird bit - his right club works perfectly with - float3 l = normalize(IN.pos-IN.lightpos.xyz); his left club works with this - float3 l = normalize(IN.lightpos.xyz-IN.pos); What do I need to change to get this to work for both at the same time ? Please help as I am knackered. Thanks, TSEDSE

OUT.pos=mul(pos, world_matrix);// world_matrix = rot, scale, trans of object

world_matrix surely can't just be your world matrix can it? Where's the view and projection transform?

I'm guessing that since you are able to see one club correctly, world_matrix is actually your world-view-projection matrix. In that case, you must pass in the real world matrix and use that when following JollyJeffer's advice.

edit: by the way, calling "mul (float3, matrix4x4);" will automatically cast the matrix4x4 to matrix3x3.