Current 3D standards require all connected components to be HDMI 1.4 (high speed w/ 3D capability) compatible. HDMI version 1.4 allows the pass through of 3D video images. If you have an older model receiver that does not feature HDMI version 1.4 it will not support 3D pass through.
However, you can still enjoy 3D by connecting the HDMI cable from your 3D source (i.e. blueray player or set-top-box) to your 3D TV directly. And then run an audio connection (i.e. digital optical, digital coax, or analog muilti-channel) from the 3D source to the receiver for the sound.