Hello all. This is not so much a vs thread, as it is a pro and con thread. Previously i have used Shader Instancing ( passing in a constant buffer and using the InstanceID to get the values ). I used this for skinned models which worked nicely ( based on the sample from nVidia ). However, i am curious to hardware instancing ( using the vertex buffer to pass the data ).

For static models, is it preferred to use hardware instancing or is really a choice of preference? what are the pros and cons to each.

To my knowledge, shader instancing is a feature of DX10+ so that is a requirement. I am going to setup hardware instancing just to test things out and get a feel for it, but i am curious to what others have seen performance and ability wise.

Thanks much

Both of the techniques you present are done in hardware so both of them are called (hardware) instancing.

When using a second vertex buffer stream, the vertex input structure gets bigger in the vertex shader and this was bad on hardware XYZ as on another card the second vertex stream was the preferred method. There is no simple answer for this question. AFAIK, In general reading data from multiple streams _may_ affect performance.

When using D3D10 (or was it D3D11) level hardware you may even provide the instance data in a general (floating point) buffer-object, without any particular structure inside which may make the code much more flexible. I'm planning to try this method in the near future. I feel that the 2nd vertex stream requires a bit too much on maintenance if I want to add more per instance input values.

Cheers!