Combine background image and model

[modhob]

What is the best way to combine a model with a background image so that the model looks realistically a part of the image?

I am new to luxrender, so that current way I am trying is to create a plane with it's diffuse set to the background image. Then I try to place my model and a sun somewhere in the scene to mimic the sun's position in the real image.
The glass material of the model seems to reflect the background image so that is good.

But the shadowing, how is that best done? Is it just something that has to be done afterward in Photoshop?

Any tips would be appreciated here? i.e. i don't even know how to set a background image yet, thus the texture on a plane.

So lets say i take a picture of my backyard, and want to make it look like there is a shiny reflective sphere on my patio. What is the best way to do this?

Thanks!

[SATtva]

See this thread for an example workflow. You can also try out camera/view texture projection methods.

[modhob]

any chance of getting a tutorial for this sort of thing? I appreciate the link, but as mentioned, I'm pretty new and could really use a step-by-step.

that motorcycle looks pretty real in that thread, even in the 1st post. So if there was something that showed how to do that, it would be great.

I'm use blender 2.58 and luxrender v.8