[Soukup]

easy steps

first have your environment underneath your object.

next make a box that is bigger than your viewport (you can't see the edges of the box from the perspective) and place it underneath your object.

Material it with a material called matte-shadow (where standard is, click and you'll see matte-shadow)

Click receive shadows.

add a skylight and an onmi for shadows (turn of shadows for the omin)

go to advanced rendering (in rendering menu and click on light tracer.

RENDER AWAY (there are better ways, but this is simple and will give u the desired effect